* portion of the elements, and so may be amenable to parallel
* execution.
*
- * This interface exports a subset of expected JDK8
+ *
This interface exports a subset of expected JDK8
* functionality.
*
*
Sample usage: Here is one (of the several) ways to compute
@@ -285,77 +285,6 @@ public class ConcurrentHashMapV8
Spliterator split();
}
- /**
- * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in
- * which additions may optionally be enabled by mapping to a
- * common value. This class cannot be directly instantiated. See
- * {@link #keySet}, {@link #keySet(Object)}, {@link #newKeySet()},
- * {@link #newKeySet(int)}.
- *
- * The view's {@code iterator} is a "weakly consistent" iterator
- * that will never throw {@link ConcurrentModificationException},
- * and guarantees to traverse elements as they existed upon
- * construction of the iterator, and may (but is not guaranteed to)
- * reflect any modifications subsequent to construction.
- */
- public static class KeySetView extends CHMView implements Set, java.io.Serializable {
- private static final long serialVersionUID = 7249069246763182397L;
- private final V value;
- KeySetView(ConcurrentHashMapV8 map, V value) { // non-public
- super(map);
- this.value = value;
- }
-
- /**
- * Returns the map backing this view.
- *
- * @return the map backing this view
- */
- public ConcurrentHashMapV8 getMap() { return map; }
-
- /**
- * Returns the default mapped value for additions,
- * or {@code null} if additions are not supported.
- *
- * @return the default mapped value for additions, or {@code null}
- * if not supported.
- */
- public V getMappedValue() { return value; }
-
- // implement Set API
-
- public boolean contains(Object o) { return map.containsKey(o); }
- public boolean remove(Object o) { return map.remove(o) != null; }
- public Iterator iterator() { return new KeyIterator(map); }
- public boolean add(K e) {
- V v;
- if ((v = value) == null)
- throw new UnsupportedOperationException();
- if (e == null)
- throw new NullPointerException();
- return map.internalPutIfAbsent(e, v) == null;
- }
- public boolean addAll(Collection c) {
- boolean added = false;
- V v;
- if ((v = value) == null)
- throw new UnsupportedOperationException();
- for (K e : c) {
- if (e == null)
- throw new NullPointerException();
- if (map.internalPutIfAbsent(e, v) == null)
- added = true;
- }
- return added;
- }
- public boolean equals(Object o) {
- Set c;
- return ((o instanceof Set) &&
- ((c = (Set)o) == this ||
- (containsAll(c) && c.containsAll(this))));
- }
- }
-
/*
* Overview:
*
@@ -370,11 +299,9 @@ public class ConcurrentHashMapV8
* can contain special values, they are defined using plain Object
* types. Similarly in turn, all internal methods that use them
* work off Object types. And similarly, so do the internal
- * methods of auxiliary iterator and view classes. All public
- * generic typed methods relay in/out of these internal methods,
- * supplying null-checks and casts as needed. This also allows
- * many of the public methods to be factored into a smaller number
- * of internal methods (although sadly not so for the five
+ * methods of auxiliary iterator and view classes. This also
+ * allows many of the public methods to be factored into a smaller
+ * number of internal methods (although sadly not so for the five
* variants of put-related operations). The validation-based
* approach explained below leads to a lot of code sprawl because
* retry-control precludes factoring into smaller methods.
@@ -390,19 +317,12 @@ public class ConcurrentHashMapV8
* as lookups check hash code and non-nullness of value before
* checking key equality.
*
- * We use the top two bits of Node hash fields for control
- * purposes -- they are available anyway because of addressing
- * constraints. As explained further below, these top bits are
- * used as follows:
- * 00 - Normal
- * 01 - Locked
- * 11 - Locked and may have a thread waiting for lock
- * 10 - Node is a forwarding node
- *
- * The lower 30 bits of each Node's hash field contain a
- * transformation of the key's hash code, except for forwarding
- * nodes, for which the lower bits are zero (and so always have
- * hash field == MOVED).
+ * We use the top (sign) bit of Node hash fields for control
+ * purposes -- it is available anyway because of addressing
+ * constraints. Nodes with negative hash fields are forwarding
+ * nodes to either TreeBins or resized tables. The lower 31 bits
+ * of each normal Node's hash field contain a transformation of
+ * the key's hash code.
*
* Insertion (via put or its variants) of the first node in an
* empty bin is performed by just CASing it to the bin. This is
@@ -411,12 +331,8 @@ public class ConcurrentHashMapV8
* delete, and replace) require locks. We do not want to waste
* the space required to associate a distinct lock object with
* each bin, so instead use the first node of a bin list itself as
- * a lock. Blocking support for these locks relies on the builtin
- * "synchronized" monitors. However, we also need a tryLock
- * construction, so we overlay these by using bits of the Node
- * hash field for lock control (see above), and so normally use
- * builtin monitors only for blocking and signalling using
- * wait/notifyAll constructions. See Node.tryAwaitLock.
+ * a lock. Locking support for these locks relies on builtin
+ * "synchronized" monitors.
*
* Using the first node of a list as a lock does not by itself
* suffice though: When a node is locked, any update must first
@@ -478,43 +394,43 @@ public class ConcurrentHashMapV8
* iterators in the same way.
*
* The table is resized when occupancy exceeds a percentage
- * threshold (nominally, 0.75, but see below). Only a single
- * thread performs the resize (using field "sizeCtl", to arrange
- * exclusion), but the table otherwise remains usable for reads
- * and updates. Resizing proceeds by transferring bins, one by
- * one, from the table to the next table. Because we are using
- * power-of-two expansion, the elements from each bin must either
- * stay at same index, or move with a power of two offset. We
- * eliminate unnecessary node creation by catching cases where old
- * nodes can be reused because their next fields won't change. On
- * average, only about one-sixth of them need cloning when a table
- * doubles. The nodes they replace will be garbage collectable as
- * soon as they are no longer referenced by any reader thread that
- * may be in the midst of concurrently traversing table. Upon
- * transfer, the old table bin contains only a special forwarding
- * node (with hash field "MOVED") that contains the next table as
- * its key. On encountering a forwarding node, access and update
- * operations restart, using the new table.
- *
- * Each bin transfer requires its bin lock. However, unlike other
- * cases, a transfer can skip a bin if it fails to acquire its
- * lock, and revisit it later (unless it is a TreeBin). Method
- * rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
- * have been skipped because of failure to acquire a lock, and
- * blocks only if none are available (i.e., only very rarely).
- * The transfer operation must also ensure that all accessible
- * bins in both the old and new table are usable by any traversal.
- * When there are no lock acquisition failures, this is arranged
- * simply by proceeding from the last bin (table.length - 1) up
- * towards the first. Upon seeing a forwarding node, traversals
- * (see class Iter) arrange to move to the new table
- * without revisiting nodes. However, when any node is skipped
- * during a transfer, all earlier table bins may have become
- * visible, so are initialized with a reverse-forwarding node back
- * to the old table until the new ones are established. (This
- * sometimes requires transiently locking a forwarding node, which
- * is possible under the above encoding.) These more expensive
- * mechanics trigger only when necessary.
+ * threshold (nominally, 0.75, but see below). Any thread
+ * noticing an overfull bin may assist in resizing after the
+ * initiating thread allocates and sets up the replacement
+ * array. However, rather than stalling, these other threads may
+ * proceed with insertions etc. The use of TreeBins shields us
+ * from the worst case effects of overfilling while resizes are in
+ * progress. Resizing proceeds by transferring bins, one by one,
+ * from the table to the next table. To enable concurrency, the
+ * next table must be (incrementally) prefilled with place-holders
+ * serving as reverse forwarders to the old table. Because we are
+ * using power-of-two expansion, the elements from each bin must
+ * either stay at same index, or move with a power of two
+ * offset. We eliminate unnecessary node creation by catching
+ * cases where old nodes can be reused because their next fields
+ * won't change. On average, only about one-sixth of them need
+ * cloning when a table doubles. The nodes they replace will be
+ * garbage collectable as soon as they are no longer referenced by
+ * any reader thread that may be in the midst of concurrently
+ * traversing table. Upon transfer, the old table bin contains
+ * only a special forwarding node (with hash field "MOVED") that
+ * contains the next table as its key. On encountering a
+ * forwarding node, access and update operations restart, using
+ * the new table.
+ *
+ * Each bin transfer requires its bin lock, which can stall
+ * waiting for locks while resizing. However, because other
+ * threads can join in and help resize rather than contend for
+ * locks, average aggregate waits become shorter as resizing
+ * progresses. The transfer operation must also ensure that all
+ * accessible bins in both the old and new table are usable by any
+ * traversal. This is arranged by proceeding from the last bin
+ * (table.length - 1) up towards the first. Upon seeing a
+ * forwarding node, traversals (see class Traverser) arrange to
+ * move to the new table without revisiting nodes. However, to
+ * ensure that no intervening nodes are skipped, bin splitting can
+ * only begin after the associated reverse-forwarders are in
+ * place.
*
* The traversal scheme also applies to partial traversals of
* ranges of bins (via an alternate Traverser constructor)
@@ -529,20 +445,20 @@ public class ConcurrentHashMapV8
* These cases attempt to override the initial capacity settings,
* but harmlessly fail to take effect in cases of races.
*
- * The element count is maintained using a LongAdder, which avoids
- * contention on updates but can encounter cache thrashing if read
- * too frequently during concurrent access. To avoid reading so
- * often, resizing is attempted either when a bin lock is
- * contended, or upon adding to a bin already holding two or more
- * nodes (checked before adding in the xIfAbsent methods, after
- * adding in others). Under uniform hash distributions, the
- * probability of this occurring at threshold is around 13%,
- * meaning that only about 1 in 8 puts check threshold (and after
- * resizing, many fewer do so). But this approximation has high
- * variance for small table sizes, so we check on any collision
- * for sizes <= 64. The bulk putAll operation further reduces
- * contention by only committing count updates upon these size
- * checks.
+ * The element count is maintained using a specialization of
+ * LongAdder. We need to incorporate a specialization rather than
+ * just use a LongAdder in order to access implicit
+ * contention-sensing that leads to creation of multiple
+ * CounterCells. The counter mechanics avoid contention on
+ * updates but can encounter cache thrashing if read too
+ * frequently during concurrent access. To avoid reading so often,
+ * resizing under contention is attempted only upon adding to a
+ * bin already holding two or more nodes. Under uniform hash
+ * distributions, the probability of this occurring at threshold
+ * is around 13%, meaning that only about 1 in 8 puts check
+ * threshold (and after resizing, many fewer do so). The bulk
+ * putAll operation further reduces contention by only committing
+ * count updates upon these size checks.
*
* Maintaining API and serialization compatibility with previous
* versions of this class introduces several oddities. Mainly: We
@@ -593,27 +509,68 @@ public class ConcurrentHashMapV8
private static final float LOAD_FACTOR = 0.75f;
/**
- * The buffer size for skipped bins during transfers. The
- * value is arbitrary but should be large enough to avoid
- * most locking stalls during resizes.
- */
- private static final int TRANSFER_BUFFER_SIZE = 32;
-
- /**
* The bin count threshold for using a tree rather than list for a
* bin. The value reflects the approximate break-even point for
* using tree-based operations.
*/
private static final int TREE_THRESHOLD = 8;
+ /**
+ * Minimum number of rebinnings per transfer step. Ranges are
+ * subdivided to allow multiple resizer threads. This value
+ * serves as a lower bound to avoid resizers encountering
+ * excessive memory contention. The value should be at least
+ * DEFAULT_CAPACITY.
+ */
+ private static final int MIN_TRANSFER_STRIDE = 16;
+
/*
- * Encodings for special uses of Node hash fields. See above for
- * explanation.
+ * Encodings for Node hash fields. See above for explanation.
*/
static final int MOVED = 0x80000000; // hash field for forwarding nodes
- static final int LOCKED = 0x40000000; // set/tested only as a bit
- static final int WAITING = 0xc0000000; // both bits set/tested together
- static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
+ static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
+
+ /** Number of CPUS, to place bounds on some sizings */
+ static final int NCPU = Runtime.getRuntime().availableProcessors();
+
+ /* ---------------- Counters -------------- */
+
+ // Adapted from LongAdder and Striped64.
+ // See their internal docs for explanation.
+
+ // A padded cell for distributing counts
+ static final class CounterCell {
+ volatile long p0, p1, p2, p3, p4, p5, p6;
+ volatile long value;
+ volatile long q0, q1, q2, q3, q4, q5, q6;
+ CounterCell(long x) { value = x; }
+ }
+
+ /**
+ * Holder for the thread-local hash code determining which
+ * CounterCell to use. The code is initialized via the
+ * counterHashCodeGenerator, but may be moved upon collisions.
+ */
+ static final class CounterHashCode {
+ int code;
+ }
+
+ /**
+ * Generates initial value for per-thread CounterHashCodes
+ */
+ static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
+
+ /**
+ * Increment for counterHashCodeGenerator. See class ThreadLocal
+ * for explanation.
+ */
+ static final int SEED_INCREMENT = 0x61c88647;
+
+ /**
+ * Per-thread counter hash codes. Shared across all instances
+ */
+ static final ThreadLocal threadCounterHashCode =
+ new ThreadLocal();
/* ---------------- Fields -------------- */
@@ -624,23 +581,51 @@ public class ConcurrentHashMapV8
transient volatile Node[] table;
/**
- * The counter maintaining number of elements.
+ * The next table to use; non-null only while resizing.
*/
- private transient final LongAdder counter;
+ private transient volatile Node[] nextTable;
+
+ /**
+ * Base counter value, used mainly when there is no contention,
+ * but also as a fallback during table initialization
+ * races. Updated via CAS.
+ */
+ private transient volatile long baseCount;
/**
* Table initialization and resizing control. When negative, the
- * table is being initialized or resized. Otherwise, when table is
- * null, holds the initial table size to use upon creation, or 0
- * for default. After initialization, holds the next element count
- * value upon which to resize the table.
+ * table is being initialized or resized: -1 for initialization,
+ * else -(1 + the number of active resizing threads). Otherwise,
+ * when table is null, holds the initial table size to use upon
+ * creation, or 0 for default. After initialization, holds the
+ * next element count value upon which to resize the table.
*/
private transient volatile int sizeCtl;
+ /**
+ * The next table index (plus one) to split while resizing.
+ */
+ private transient volatile int transferIndex;
+
+ /**
+ * The least available table index to split while resizing.
+ */
+ private transient volatile int transferOrigin;
+
+ /**
+ * Spinlock (locked via CAS) used when resizing and/or creating Cells.
+ */
+ private transient volatile int counterBusy;
+
+ /**
+ * Table of counter cells. When non-null, size is a power of 2.
+ */
+ private transient volatile CounterCell[] counterCells;
+
// views
private transient KeySetView keySet;
- private transient Values values;
- private transient EntrySet entrySet;
+ private transient ValuesView values;
+ private transient EntrySetView entrySet;
/** For serialization compatibility. Null unless serialized; see below */
private Segment[] segments;
@@ -659,16 +644,16 @@ public class ConcurrentHashMapV8
* inline assignments below.
*/
- static final Node tabAt(Node[] tab, int i) { // used by Iter
- return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<
* non-null.
*/
static class Node {
- volatile int hash;
+ final int hash;
final Object key;
volatile Object val;
volatile Node next;
@@ -695,76 +680,6 @@ public class ConcurrentHashMapV8
this.val = val;
this.next = next;
}
-
- /** CompareAndSet the hash field */
- final boolean casHash(int cmp, int val) {
- return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
- }
-
- /** The number of spins before blocking for a lock */
- static final int MAX_SPINS =
- Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
-
- /**
- * Spins a while if LOCKED bit set and this node is the first
- * of its bin, and then sets WAITING bits on hash field and
- * blocks (once) if they are still set. It is OK for this
- * method to return even if lock is not available upon exit,
- * which enables these simple single-wait mechanics.
- *
- * The corresponding signalling operation is performed within
- * callers: Upon detecting that WAITING has been set when
- * unlocking lock (via a failed CAS from non-waiting LOCKED
- * state), unlockers acquire the sync lock and perform a
- * notifyAll.
- *
- * The initial sanity check on tab and bounds is not currently
- * necessary in the only usages of this method, but enables
- * use in other future contexts.
- */
- final void tryAwaitLock(Node[] tab, int i) {
- if (tab != null && i >= 0 && i < tab.length) { // sanity check
- int r = ThreadLocalRandom.current().nextInt(); // randomize spins
- int spins = MAX_SPINS, h;
- while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
- if (spins >= 0) {
- r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
- if (r >= 0 && --spins == 0)
- Thread.yield(); // yield before block
- }
- else if (casHash(h, h | WAITING)) {
- synchronized (this) {
- if (tabAt(tab, i) == this &&
- (hash & WAITING) == WAITING) {
- try {
- wait();
- } catch (InterruptedException ie) {
- Thread.currentThread().interrupt();
- }
- }
- else
- notifyAll(); // possibly won race vs signaller
- }
- break;
- }
- }
- }
- }
-
- // Unsafe mechanics for casHash
- private static final sun.misc.Unsafe UNSAFE;
- private static final long hashOffset;
-
- static {
- try {
- UNSAFE = getUnsafe();
- Class k = Node.class;
- hashOffset = UNSAFE.objectFieldOffset
- (k.getDeclaredField("hash"));
- } catch (Exception e) {
- throw new Error(e);
- }
- }
}
/* ---------------- TreeBins -------------- */
@@ -910,16 +825,17 @@ public class ConcurrentHashMapV8
if (c != (pc = pk.getClass()) ||
!(k instanceof Comparable) ||
(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
- dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
- TreeNode r = null, s = null, pl, pr;
- if (dir >= 0) {
- if ((pl = p.left) != null && h <= pl.hash)
- s = pl;
+ if ((dir = (c == pc) ? 0 :
+ c.getName().compareTo(pc.getName())) == 0) {
+ TreeNode r = null, pl, pr; // check both sides
+ if ((pr = p.right) != null && h >= pr.hash &&
+ (r = getTreeNode(h, k, pr)) != null)
+ return r;
+ else if ((pl = p.left) != null && h <= pl.hash)
+ dir = -1;
+ else // nothing there
+ return null;
}
- else if ((pr = p.right) != null && h >= pr.hash)
- s = pr;
- if (s != null && (r = getTreeNode(h, k, s)) != null)
- return r;
}
}
else
@@ -946,7 +862,7 @@ public class ConcurrentHashMapV8
}
break;
}
- else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
+ else if (e.hash == h && k.equals(e.key)) {
r = e;
break;
}
@@ -974,11 +890,14 @@ public class ConcurrentHashMapV8
if (c != (pc = pk.getClass()) ||
!(k instanceof Comparable) ||
(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
- dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
- TreeNode r = null, s = null, pl, pr;
- if (dir >= 0) {
- if ((pl = p.left) != null && h <= pl.hash)
- s = pl;
+ TreeNode s = null, r = null, pr;
+ if ((dir = (c == pc) ? 0 :
+ c.getName().compareTo(pc.getName())) == 0) {
+ if ((pr = p.right) != null && h >= pr.hash &&
+ (r = getTreeNode(h, k, pr)) != null)
+ return r;
+ else // continue left
+ dir = -1;
}
else if ((pr = p.right) != null && h >= pr.hash)
s = pr;
@@ -1165,7 +1084,8 @@ public class ConcurrentHashMapV8
sl.red = false;
sib.red = true;
rotateRight(sib);
- sib = (xp = x.parent) == null ? null : xp.right;
+ sib = (xp = x.parent) == null ?
+ null : xp.right;
}
if (sib != null) {
sib.red = (xp == null) ? false : xp.red;
@@ -1203,7 +1123,8 @@ public class ConcurrentHashMapV8
sr.red = false;
sib.red = true;
rotateLeft(sib);
- sib = (xp = x.parent) == null ? null : xp.left;
+ sib = (xp = x.parent) == null ?
+ null : xp.left;
}
if (sib != null) {
sib.red = (xp == null) ? false : xp.red;
@@ -1233,7 +1154,7 @@ public class ConcurrentHashMapV8
/* ---------------- Collision reduction methods -------------- */
/**
- * Spreads higher bits to lower, and also forces top 2 bits to 0.
+ * Spreads higher bits to lower, and also forces top bit to 0.
* Because the table uses power-of-two masking, sets of hashes
* that vary only in bits above the current mask will always
* collide. (Among known examples are sets of Float keys holding
@@ -1251,16 +1172,14 @@ public class ConcurrentHashMapV8
}
/**
- * Replaces a list bin with a tree bin. Call only when locked.
- * Fails to replace if the given key is non-comparable or table
- * is, or needs, resizing.
+ * Replaces a list bin with a tree bin if key is comparable. Call
+ * only when locked.
*/
private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
- if ((key instanceof Comparable) &&
- (tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
+ if (key instanceof Comparable) {
TreeBin t = new TreeBin();
for (Node e = tabAt(tab, index); e != null; e = e.next)
- t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
+ t.putTreeNode(e.hash, e.key, e.val);
setTabAt(tab, index, new Node(MOVED, t, null, null));
}
}
@@ -1268,22 +1187,22 @@ public class ConcurrentHashMapV8
/* ---------------- Internal access and update methods -------------- */
/** Implementation for get and containsKey */
- private final Object internalGet(Object k) {
+ @SuppressWarnings("unchecked") private final V internalGet(Object k) {
int h = spread(k.hashCode());
retry: for (Node[] tab = table; tab != null;) {
- Node e, p; Object ek, ev; int eh; // locals to read fields once
+ Node e; Object ek, ev; int eh; // locals to read fields once
for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
- if ((eh = e.hash) == MOVED) {
+ if ((eh = e.hash) < 0) {
if ((ek = e.key) instanceof TreeBin) // search TreeBin
- return ((TreeBin)ek).getValue(h, k);
+ return (V)((TreeBin)ek).getValue(h, k);
else { // restart with new table
tab = (Node[])ek;
continue retry;
}
}
- else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
+ else if (eh == h && (ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek)))
- return ev;
+ return (V)ev;
}
break;
}
@@ -1295,7 +1214,8 @@ public class ConcurrentHashMapV8
* Replaces node value with v, conditional upon match of cv if
* non-null. If resulting value is null, delete.
*/
- private final Object internalReplace(Object k, Object v, Object cv) {
+ @SuppressWarnings("unchecked") private final V internalReplace
+ (Object k, V v, Object cv) {
int h = spread(k.hashCode());
Object oldVal = null;
for (Node[] tab = table;;) {
@@ -1303,7 +1223,7 @@ public class ConcurrentHashMapV8
if (tab == null ||
(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
break;
- else if ((fh = f.hash) == MOVED) {
+ else if ((fh = f.hash) < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
boolean validated = false;
@@ -1329,28 +1249,24 @@ public class ConcurrentHashMapV8
}
if (validated) {
if (deleted)
- counter.add(-1L);
+ addCount(-1L, -1);
break;
}
}
else
tab = (Node[])fk;
}
- else if ((fh & HASH_BITS) != h && f.next == null) // precheck
+ else if (fh != h && f.next == null) // precheck
break; // rules out possible existence
- else if ((fh & LOCKED) != 0) {
- checkForResize(); // try resizing if can't get lock
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
+ else {
boolean validated = false;
boolean deleted = false;
- try {
+ synchronized(f) {
if (tabAt(tab, i) == f) {
validated = true;
for (Node e = f, pred = null;;) {
Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
+ if (e.hash == h &&
((ev = e.val) != null) &&
((ek = e.key) == k || k.equals(ek))) {
if (cv == null || cv == ev || cv.equals(ev)) {
@@ -1371,372 +1287,227 @@ public class ConcurrentHashMapV8
break;
}
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
}
if (validated) {
if (deleted)
- counter.add(-1L);
+ addCount(-1L, -1);
break;
}
}
}
- return oldVal;
+ return (V)oldVal;
}
/*
- * Internal versions of the six insertion methods, each a
- * little more complicated than the last. All have
- * the same basic structure as the first (internalPut):
+ * Internal versions of insertion methods
+ * All have the same basic structure as the first (internalPut):
* 1. If table uninitialized, create
* 2. If bin empty, try to CAS new node
* 3. If bin stale, use new table
* 4. if bin converted to TreeBin, validate and relay to TreeBin methods
* 5. Lock and validate; if valid, scan and add or update
*
- * The others interweave other checks and/or alternative actions:
- * * Plain put checks for and performs resize after insertion.
- * * putIfAbsent prescans for mapping without lock (and fails to add
- * if present), which also makes pre-emptive resize checks worthwhile.
- * * computeIfAbsent extends form used in putIfAbsent with additional
- * mechanics to deal with, calls, potential exceptions and null
- * returns from function call.
- * * compute uses the same function-call mechanics, but without
- * the prescans
- * * merge acts as putIfAbsent in the absent case, but invokes the
- * update function if present
- * * putAll attempts to pre-allocate enough table space
- * and more lazily performs count updates and checks.
- *
- * Someday when details settle down a bit more, it might be worth
- * some factoring to reduce sprawl.
+ * The putAll method differs mainly in attempting to pre-allocate
+ * enough table space, and also more lazily performs count updates
+ * and checks.
+ *
+ * Most of the function-accepting methods can't be factored nicely
+ * because they require different functional forms, so instead
+ * sprawl out similar mechanics.
*/
- /** Implementation for put */
- private final Object internalPut(Object k, Object v) {
+ /** Implementation for put and putIfAbsent */
+ @SuppressWarnings("unchecked") private final V internalPut
+ (K k, V v, boolean onlyIfAbsent) {
+ if (k == null || v == null) throw new NullPointerException();
int h = spread(k.hashCode());
- int count = 0;
+ int len = 0;
for (Node[] tab = table;;) {
- int i; Node f; int fh; Object fk;
+ int i, fh; Node f; Object fk, fv;
if (tab == null)
tab = initTable();
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
if (casTabAt(tab, i, null, new Node(h, k, v, null)))
break; // no lock when adding to empty bin
}
- else if ((fh = f.hash) == MOVED) {
+ else if ((fh = f.hash) < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
Object oldVal = null;
t.acquire(0);
try {
if (tabAt(tab, i) == f) {
- count = 2;
+ len = 2;
TreeNode p = t.putTreeNode(h, k, v);
if (p != null) {
oldVal = p.val;
- p.val = v;
+ if (!onlyIfAbsent)
+ p.val = v;
}
}
} finally {
t.release(0);
}
- if (count != 0) {
+ if (len != 0) {
if (oldVal != null)
- return oldVal;
+ return (V)oldVal;
break;
}
}
else
tab = (Node[])fk;
}
- else if ((fh & LOCKED) != 0) {
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
+ else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
+ ((fk = f.key) == k || k.equals(fk))) // peek while nearby
+ return (V)fv;
+ else {
Object oldVal = null;
- try { // needed in case equals() throws
+ synchronized(f) {
if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f;; ++count) {
+ len = 1;
+ for (Node e = f;; ++len) {
Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
+ if (e.hash == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
oldVal = ev;
- e.val = v;
+ if (!onlyIfAbsent)
+ e.val = v;
break;
}
Node last = e;
if ((e = e.next) == null) {
last.next = new Node(h, k, v, null);
- if (count >= TREE_THRESHOLD)
+ if (len >= TREE_THRESHOLD)
replaceWithTreeBin(tab, i, k);
break;
}
}
}
- } finally { // unlock and signal if needed
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
}
- if (count != 0) {
+ if (len != 0) {
if (oldVal != null)
- return oldVal;
- if (tab.length <= 64)
- count = 2;
+ return (V)oldVal;
break;
}
}
}
- counter.add(1L);
- if (count > 1)
- checkForResize();
- return null;
- }
-
- /** Implementation for putIfAbsent */
- private final Object internalPutIfAbsent(Object k, Object v) {
- int h = spread(k.hashCode());
- int count = 0;
- for (Node[] tab = table;;) {
- int i; Node f; int fh; Object fk, fv;
- if (tab == null)
- tab = initTable();
- else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
- if (casTabAt(tab, i, null, new Node(h, k, v, null)))
- break;
- }
- else if ((fh = f.hash) == MOVED) {
- if ((fk = f.key) instanceof TreeBin) {
- TreeBin t = (TreeBin)fk;
- Object oldVal = null;
- t.acquire(0);
- try {
- if (tabAt(tab, i) == f) {
- count = 2;
- TreeNode p = t.putTreeNode(h, k, v);
- if (p != null)
- oldVal = p.val;
- }
- } finally {
- t.release(0);
- }
- if (count != 0) {
- if (oldVal != null)
- return oldVal;
- break;
- }
- }
- else
- tab = (Node[])fk;
- }
- else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
- ((fk = f.key) == k || k.equals(fk)))
- return fv;
- else {
- Node g = f.next;
- if (g != null) { // at least 2 nodes -- search and maybe resize
- for (Node e = g;;) {
- Object ek, ev;
- if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
- ((ek = e.key) == k || k.equals(ek)))
- return ev;
- if ((e = e.next) == null) {
- checkForResize();
- break;
- }
- }
- }
- if (((fh = f.hash) & LOCKED) != 0) {
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
- Object oldVal = null;
- try {
- if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f;; ++count) {
- Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
- (ev = e.val) != null &&
- ((ek = e.key) == k || k.equals(ek))) {
- oldVal = ev;
- break;
- }
- Node last = e;
- if ((e = e.next) == null) {
- last.next = new Node(h, k, v, null);
- if (count >= TREE_THRESHOLD)
- replaceWithTreeBin(tab, i, k);
- break;
- }
- }
- }
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
- }
- if (count != 0) {
- if (oldVal != null)
- return oldVal;
- if (tab.length <= 64)
- count = 2;
- break;
- }
- }
- }
- }
- counter.add(1L);
- if (count > 1)
- checkForResize();
+ addCount(1L, len);
return null;
}
/** Implementation for computeIfAbsent */
- private final Object internalComputeIfAbsent(K k,
- Fun mf) {
+ @SuppressWarnings("unchecked") private final V internalComputeIfAbsent
+ (K k, Fun mf) {
+ if (k == null || mf == null)
+ throw new NullPointerException();
int h = spread(k.hashCode());
Object val = null;
- int count = 0;
+ int len = 0;
for (Node[] tab = table;;) {
- Node f; int i, fh; Object fk, fv;
+ Node f; int i; Object fk;
if (tab == null)
tab = initTable();
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
- Node node = new Node(fh = h | LOCKED, k, null, null);
- if (casTabAt(tab, i, null, node)) {
- count = 1;
- try {
- if ((val = mf.apply(k)) != null)
- node.val = val;
- } finally {
- if (val == null)
- setTabAt(tab, i, null);
- if (!node.casHash(fh, h)) {
- node.hash = h;
- synchronized (node) { node.notifyAll(); };
+ Node node = new Node(h, k, null, null);
+ synchronized(node) {
+ if (casTabAt(tab, i, null, node)) {
+ len = 1;
+ try {
+ if ((val = mf.apply(k)) != null)
+ node.val = val;
+ } finally {
+ if (val == null)
+ setTabAt(tab, i, null);
}
}
}
- if (count != 0)
+ if (len != 0)
break;
}
- else if ((fh = f.hash) == MOVED) {
+ else if (f.hash < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
boolean added = false;
t.acquire(0);
try {
if (tabAt(tab, i) == f) {
- count = 1;
+ len = 1;
TreeNode p = t.getTreeNode(h, k, t.root);
if (p != null)
val = p.val;
else if ((val = mf.apply(k)) != null) {
added = true;
- count = 2;
+ len = 2;
t.putTreeNode(h, k, val);
}
}
} finally {
t.release(0);
}
- if (count != 0) {
+ if (len != 0) {
if (!added)
- return val;
+ return (V)val;
break;
}
}
else
tab = (Node[])fk;
}
- else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
- ((fk = f.key) == k || k.equals(fk)))
- return fv;
else {
- Node g = f.next;
- if (g != null) {
- for (Node e = g;;) {
- Object ek, ev;
- if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
- ((ek = e.key) == k || k.equals(ek)))
- return ev;
- if ((e = e.next) == null) {
- checkForResize();
- break;
- }
- }
+ for (Node e = f; e != null; e = e.next) { // prescan
+ Object ek, ev;
+ if (e.hash == h && (ev = e.val) != null &&
+ ((ek = e.key) == k || k.equals(ek)))
+ return (V)ev;
}
- if (((fh = f.hash) & LOCKED) != 0) {
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
- boolean added = false;
- try {
- if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f;; ++count) {
- Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
- (ev = e.val) != null &&
- ((ek = e.key) == k || k.equals(ek))) {
- val = ev;
- break;
- }
- Node last = e;
- if ((e = e.next) == null) {
- if ((val = mf.apply(k)) != null) {
- added = true;
- last.next = new Node(h, k, val, null);
- if (count >= TREE_THRESHOLD)
- replaceWithTreeBin(tab, i, k);
- }
- break;
+ boolean added = false;
+ synchronized(f) {
+ if (tabAt(tab, i) == f) {
+ len = 1;
+ for (Node e = f;; ++len) {
+ Object ek, ev;
+ if (e.hash == h &&
+ (ev = e.val) != null &&
+ ((ek = e.key) == k || k.equals(ek))) {
+ val = ev;
+ break;
+ }
+ Node last = e;
+ if ((e = e.next) == null) {
+ if ((val = mf.apply(k)) != null) {
+ added = true;
+ last.next = new Node(h, k, val, null);
+ if (len >= TREE_THRESHOLD)
+ replaceWithTreeBin(tab, i, k);
}
+ break;
}
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
- }
- if (count != 0) {
- if (!added)
- return val;
- if (tab.length <= 64)
- count = 2;
- break;
}
}
+ if (len != 0) {
+ if (!added)
+ return (V)val;
+ break;
+ }
}
}
- if (val != null) {
- counter.add(1L);
- if (count > 1)
- checkForResize();
- }
- return val;
+ if (val != null)
+ addCount(1L, len);
+ return (V)val;
}
/** Implementation for compute */
- @SuppressWarnings("unchecked") private final Object internalCompute
- (K k, boolean onlyIfPresent, BiFun mf) {
+ @SuppressWarnings("unchecked") private final V internalCompute
+ (K k, boolean onlyIfPresent,
+ BiFun mf) {
+ if (k == null || mf == null)
+ throw new NullPointerException();
int h = spread(k.hashCode());
Object val = null;
int delta = 0;
- int count = 0;
+ int len = 0;
for (Node[] tab = table;;) {
Node f; int i, fh; Object fk;
if (tab == null)
@@ -1744,40 +1515,40 @@ public class ConcurrentHashMapV8
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
if (onlyIfPresent)
break;
- Node node = new Node(fh = h | LOCKED, k, null, null);
- if (casTabAt(tab, i, null, node)) {
- try {
- count = 1;
- if ((val = mf.apply(k, null)) != null) {
- node.val = val;
- delta = 1;
- }
- } finally {
- if (delta == 0)
- setTabAt(tab, i, null);
- if (!node.casHash(fh, h)) {
- node.hash = h;
- synchronized (node) { node.notifyAll(); };
+ Node node = new Node(h, k, null, null);
+ synchronized(node) {
+ if (casTabAt(tab, i, null, node)) {
+ try {
+ len = 1;
+ if ((val = mf.apply(k, null)) != null) {
+ node.val = val;
+ delta = 1;
+ }
+ } finally {
+ if (delta == 0)
+ setTabAt(tab, i, null);
}
}
}
- if (count != 0)
+ if (len != 0)
break;
}
- else if ((fh = f.hash) == MOVED) {
+ else if ((fh = f.hash) < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
t.acquire(0);
try {
if (tabAt(tab, i) == f) {
- count = 1;
+ len = 1;
TreeNode p = t.getTreeNode(h, k, t.root);
+ if (p == null && onlyIfPresent)
+ break;
Object pv = (p == null) ? null : p.val;
if ((val = mf.apply(k, (V)pv)) != null) {
if (p != null)
p.val = val;
else {
- count = 2;
+ len = 2;
delta = 1;
t.putTreeNode(h, k, val);
}
@@ -1790,23 +1561,19 @@ public class ConcurrentHashMapV8
} finally {
t.release(0);
}
- if (count != 0)
+ if (len != 0)
break;
}
else
tab = (Node[])fk;
}
- else if ((fh & LOCKED) != 0) {
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
- try {
+ else {
+ synchronized(f) {
if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f, pred = null;; ++count) {
+ len = 1;
+ for (Node e = f, pred = null;; ++len) {
Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
+ if (e.hash == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
val = mf.apply(k, (V)ev);
@@ -1824,46 +1591,38 @@ public class ConcurrentHashMapV8
}
pred = e;
if ((e = e.next) == null) {
- if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
+ if (!onlyIfPresent &&
+ (val = mf.apply(k, null)) != null) {
pred.next = new Node(h, k, val, null);
delta = 1;
- if (count >= TREE_THRESHOLD)
+ if (len >= TREE_THRESHOLD)
replaceWithTreeBin(tab, i, k);
}
break;
}
}
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
}
- if (count != 0) {
- if (tab.length <= 64)
- count = 2;
+ if (len != 0)
break;
- }
}
}
- if (delta != 0) {
- counter.add((long)delta);
- if (count > 1)
- checkForResize();
- }
- return val;
+ if (delta != 0)
+ addCount((long)delta, len);
+ return (V)val;
}
/** Implementation for merge */
- @SuppressWarnings("unchecked") private final Object internalMerge
+ @SuppressWarnings("unchecked") private final V internalMerge
(K k, V v, BiFun mf) {
+ if (k == null || v == null || mf == null)
+ throw new NullPointerException();
int h = spread(k.hashCode());
Object val = null;
int delta = 0;
- int count = 0;
+ int len = 0;
for (Node[] tab = table;;) {
- int i; Node f; int fh; Object fk, fv;
+ int i; Node f; Object fk, fv;
if (tab == null)
tab = initTable();
else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
@@ -1873,20 +1632,20 @@ public class ConcurrentHashMapV8
break;
}
}
- else if ((fh = f.hash) == MOVED) {
+ else if (f.hash < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
t.acquire(0);
try {
if (tabAt(tab, i) == f) {
- count = 1;
+ len = 1;
TreeNode p = t.getTreeNode(h, k, t.root);
val = (p == null) ? v : mf.apply((V)p.val, v);
if (val != null) {
if (p != null)
p.val = val;
else {
- count = 2;
+ len = 2;
delta = 1;
t.putTreeNode(h, k, val);
}
@@ -1899,26 +1658,22 @@ public class ConcurrentHashMapV8
} finally {
t.release(0);
}
- if (count != 0)
+ if (len != 0)
break;
}
else
tab = (Node[])fk;
}
- else if ((fh & LOCKED) != 0) {
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
- try {
+ else {
+ synchronized(f) {
if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f, pred = null;; ++count) {
+ len = 1;
+ for (Node e = f, pred = null;; ++len) {
Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
+ if (e.hash == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
- val = mf.apply(v, (V)ev);
+ val = mf.apply((V)ev, v);
if (val != null)
e.val = val;
else {
@@ -1936,31 +1691,20 @@ public class ConcurrentHashMapV8
val = v;
pred.next = new Node(h, k, val, null);
delta = 1;
- if (count >= TREE_THRESHOLD)
+ if (len >= TREE_THRESHOLD)
replaceWithTreeBin(tab, i, k);
break;
}
}
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
}
- if (count != 0) {
- if (tab.length <= 64)
- count = 2;
+ if (len != 0)
break;
- }
}
}
- if (delta != 0) {
- counter.add((long)delta);
- if (count > 1)
- checkForResize();
- }
- return val;
+ if (delta != 0)
+ addCount((long)delta, len);
+ return (V)val;
}
/** Implementation for putAll */
@@ -1987,7 +1731,7 @@ public class ConcurrentHashMapV8
break;
}
}
- else if ((fh = f.hash) == MOVED) {
+ else if ((fh = f.hash) < 0) {
if ((fk = f.key) instanceof TreeBin) {
TreeBin t = (TreeBin)fk;
boolean validated = false;
@@ -2012,20 +1756,14 @@ public class ConcurrentHashMapV8
else
tab = (Node[])fk;
}
- else if ((fh & LOCKED) != 0) {
- counter.add(delta);
- delta = 0L;
- checkForResize();
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
- int count = 0;
- try {
+ else {
+ int len = 0;
+ synchronized(f) {
if (tabAt(tab, i) == f) {
- count = 1;
- for (Node e = f;; ++count) {
+ len = 1;
+ for (Node e = f;; ++len) {
Object ek, ev;
- if ((e.hash & HASH_BITS) == h &&
+ if (e.hash == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
e.val = v;
@@ -2035,37 +1773,84 @@ public class ConcurrentHashMapV8
if ((e = e.next) == null) {
++delta;
last.next = new Node(h, k, v, null);
- if (count >= TREE_THRESHOLD)
+ if (len >= TREE_THRESHOLD)
replaceWithTreeBin(tab, i, k);
break;
}
}
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
}
- if (count != 0) {
- if (count > 1) {
- counter.add(delta);
- delta = 0L;
- checkForResize();
- }
+ if (len != 0) {
+ if (len > 1)
+ addCount(delta, len);
break;
}
}
}
}
} finally {
- if (delta != 0)
- counter.add(delta);
+ if (delta != 0L)
+ addCount(delta, 2);
}
if (npe)
throw new NullPointerException();
}
+ /**
+ * Implementation for clear. Steps through each bin, removing all
+ * nodes.
+ */
+ private final void internalClear() {
+ long delta = 0L; // negative number of deletions
+ int i = 0;
+ Node[] tab = table;
+ while (tab != null && i < tab.length) {
+ Node f = tabAt(tab, i);
+ if (f == null)
+ ++i;
+ else if (f.hash < 0) {
+ Object fk;
+ if ((fk = f.key) instanceof TreeBin) {
+ TreeBin t = (TreeBin)fk;
+ t.acquire(0);
+ try {
+ if (tabAt(tab, i) == f) {
+ for (Node p = t.first; p != null; p = p.next) {
+ if (p.val != null) { // (currently always true)
+ p.val = null;
+ --delta;
+ }
+ }
+ t.first = null;
+ t.root = null;
+ ++i;
+ }
+ } finally {
+ t.release(0);
+ }
+ }
+ else
+ tab = (Node[])fk;
+ }
+ else {
+ synchronized(f) {
+ if (tabAt(tab, i) == f) {
+ for (Node e = f; e != null; e = e.next) {
+ if (e.val != null) { // (currently always true)
+ e.val = null;
+ --delta;
+ }
+ }
+ setTabAt(tab, i, null);
+ ++i;
+ }
+ }
+ }
+ }
+ if (delta != 0L)
+ addCount(delta, -1);
+ }
+
/* ---------------- Table Initialization and Resizing -------------- */
/**
@@ -2090,7 +1875,7 @@ public class ConcurrentHashMapV8
while ((tab = table) == null) {
if ((sc = sizeCtl) < 0)
Thread.yield(); // lost initialization race; just spin
- else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
+ else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if ((tab = table) == null) {
int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
@@ -2107,24 +1892,47 @@ public class ConcurrentHashMapV8
}
/**
- * If table is too small and not already resizing, creates next
- * table and transfers bins. Rechecks occupancy after a transfer
- * to see if another resize is already needed because resizings
- * are lagging additions.
- */
- private final void checkForResize() {
- Node[] tab; int n, sc;
- while ((tab = table) != null &&
- (n = tab.length) < MAXIMUM_CAPACITY &&
- (sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
- UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
- try {
- if (tab == table) {
- table = rebuild(tab);
- sc = (n << 1) - (n >>> 1);
+ * Adds to count, and if table is too small and not already
+ * resizing, initiates transfer. If already resizing, helps
+ * perform transfer if work is available. Rechecks occupancy
+ * after a transfer to see if another resize is already needed
+ * because resizings are lagging additions.
+ *
+ * @param x the count to add
+ * @param check if <0, don't check resize, if <= 1 only check if uncontended
+ */
+ private final void addCount(long x, int check) {
+ CounterCell[] as; long b, s;
+ if ((as = counterCells) != null ||
+ !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
+ CounterHashCode hc; CounterCell a; long v; int m;
+ boolean uncontended = true;
+ if ((hc = threadCounterHashCode.get()) == null ||
+ as == null || (m = as.length - 1) < 0 ||
+ (a = as[m & hc.code]) == null ||
+ !(uncontended =
+ U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
+ fullAddCount(x, hc, uncontended);
+ return;
+ }
+ if (check <= 1)
+ return;
+ s = sumCount();
+ }
+ if (check >= 0) {
+ Node[] tab, nt; int sc;
+ while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
+ tab.length < MAXIMUM_CAPACITY) {
+ if (sc < 0) {
+ if (sc == -1 || transferIndex <= transferOrigin ||
+ (nt = nextTable) == null)
+ break;
+ if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
+ transfer(tab, nt);
}
- } finally {
- sizeCtl = sc;
+ else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
+ transfer(tab, null);
+ s = sumCount();
}
}
}
@@ -2142,7 +1950,7 @@ public class ConcurrentHashMapV8
Node[] tab = table; int n;
if (tab == null || (n = tab.length) == 0) {
n = (sc > c) ? sc : c;
- if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
+ if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if (table == tab) {
table = new Node[n];
@@ -2155,257 +1963,261 @@ public class ConcurrentHashMapV8
}
else if (c <= sc || n >= MAXIMUM_CAPACITY)
break;
- else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
- try {
- if (table == tab) {
- table = rebuild(tab);
- sc = (n << 1) - (n >>> 1);
- }
- } finally {
- sizeCtl = sc;
- }
- }
+ else if (tab == table &&
+ U.compareAndSwapInt(this, SIZECTL, sc, -2))
+ transfer(tab, null);
}
}
/*
* Moves and/or copies the nodes in each bin to new table. See
* above for explanation.
- *
- * @return the new table
*/
- private static final Node[] rebuild(Node[] tab) {
- int n = tab.length;
- Node[] nextTab = new Node[n << 1];
+ private final void transfer(Node[] tab, Node[] nextTab) {
+ int n = tab.length, stride;
+ if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
+ stride = MIN_TRANSFER_STRIDE; // subdivide range
+ if (nextTab == null) { // initiating
+ try {
+ nextTab = new Node[n << 1];
+ } catch(Throwable ex) { // try to cope with OOME
+ sizeCtl = Integer.MAX_VALUE;
+ return;
+ }
+ nextTable = nextTab;
+ transferOrigin = n;
+ transferIndex = n;
+ Node rev = new Node(MOVED, tab, null, null);
+ for (int k = n; k > 0;) { // progressively reveal ready slots
+ int nextk = k > stride? k - stride : 0;
+ for (int m = nextk; m < k; ++m)
+ nextTab[m] = rev;
+ for (int m = n + nextk; m < n + k; ++m)
+ nextTab[m] = rev;
+ U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
+ }
+ }
+ int nextn = nextTab.length;
Node fwd = new Node(MOVED, nextTab, null, null);
- int[] buffer = null; // holds bins to revisit; null until needed
- Node rev = null; // reverse forwarder; null until needed
- int nbuffered = 0; // the number of bins in buffer list
- int bufferIndex = 0; // buffer index of current buffered bin
- int bin = n - 1; // current non-buffered bin or -1 if none
-
- for (int i = bin;;) { // start upwards sweep
- int fh; Node f;
- if ((f = tabAt(tab, i)) == null) {
- if (bin >= 0) { // Unbuffered; no lock needed (or available)
- if (!casTabAt(tab, i, f, fwd))
- continue;
- }
- else { // transiently use a locked forwarding node
- Node g = new Node(MOVED|LOCKED, nextTab, null, null);
- if (!casTabAt(tab, i, f, g))
- continue;
+ boolean advance = true;
+ for (int i = 0, bound = 0;;) {
+ int nextIndex, nextBound; Node f; Object fk;
+ while (advance) {
+ if (--i >= bound)
+ advance = false;
+ else if ((nextIndex = transferIndex) <= transferOrigin) {
+ i = -1;
+ advance = false;
+ }
+ else if (U.compareAndSwapInt
+ (this, TRANSFERINDEX, nextIndex,
+ nextBound = (nextIndex > stride?
+ nextIndex - stride : 0))) {
+ bound = nextBound;
+ i = nextIndex - 1;
+ advance = false;
+ }
+ }
+ if (i < 0 || i >= n || i + n >= nextn) {
+ for (int sc;;) {
+ if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
+ if (sc == -1) {
+ nextTable = null;
+ table = nextTab;
+ sizeCtl = (n << 1) - (n >>> 1);
+ }
+ return;
+ }
+ }
+ }
+ else if ((f = tabAt(tab, i)) == null) {
+ if (casTabAt(tab, i, null, fwd)) {
setTabAt(nextTab, i, null);
setTabAt(nextTab, i + n, null);
- setTabAt(tab, i, fwd);
- if (!g.casHash(MOVED|LOCKED, MOVED)) {
- g.hash = MOVED;
- synchronized (g) { g.notifyAll(); }
- }
+ advance = true;
}
}
- else if ((fh = f.hash) == MOVED) {
- Object fk = f.key;
- if (fk instanceof TreeBin) {
- TreeBin t = (TreeBin)fk;
- boolean validated = false;
- t.acquire(0);
- try {
- if (tabAt(tab, i) == f) {
- validated = true;
- splitTreeBin(nextTab, i, t);
- setTabAt(tab, i, fwd);
+ else if (f.hash >= 0) {
+ synchronized(f) {
+ if (tabAt(tab, i) == f) {
+ int runBit = f.hash & n;
+ Node lastRun = f, lo = null, hi = null;
+ for (Node p = f.next; p != null; p = p.next) {
+ int b = p.hash & n;
+ if (b != runBit) {
+ runBit = b;
+ lastRun = p;
+ }
}
- } finally {
- t.release(0);
+ if (runBit == 0)
+ lo = lastRun;
+ else
+ hi = lastRun;
+ for (Node p = f; p != lastRun; p = p.next) {
+ int ph = p.hash;
+ Object pk = p.key, pv = p.val;
+ if ((ph & n) == 0)
+ lo = new Node(ph, pk, pv, lo);
+ else
+ hi = new Node(ph, pk, pv, hi);
+ }
+ setTabAt(nextTab, i, lo);
+ setTabAt(nextTab, i + n, hi);
+ setTabAt(tab, i, fwd);
+ advance = true;
}
- if (!validated)
- continue;
}
}
- else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
- boolean validated = false;
- try { // split to lo and hi lists; copying as needed
+ else if ((fk = f.key) instanceof TreeBin) {
+ TreeBin t = (TreeBin)fk;
+ t.acquire(0);
+ try {
if (tabAt(tab, i) == f) {
- validated = true;
- splitBin(nextTab, i, f);
+ TreeBin lt = new TreeBin();
+ TreeBin ht = new TreeBin();
+ int lc = 0, hc = 0;
+ for (Node e = t.first; e != null; e = e.next) {
+ int h = e.hash;
+ Object k = e.key, v = e.val;
+ if ((h & n) == 0) {
+ ++lc;
+ lt.putTreeNode(h, k, v);
+ }
+ else {
+ ++hc;
+ ht.putTreeNode(h, k, v);
+ }
+ }
+ Node ln, hn; // throw away trees if too small
+ if (lc < TREE_THRESHOLD) {
+ ln = null;
+ for (Node p = lt.first; p != null; p = p.next)
+ ln = new Node(p.hash, p.key, p.val, ln);
+ }
+ else
+ ln = new Node(MOVED, lt, null, null);
+ setTabAt(nextTab, i, ln);
+ if (hc < TREE_THRESHOLD) {
+ hn = null;
+ for (Node p = ht.first; p != null; p = p.next)
+ hn = new Node(p.hash, p.key, p.val, hn);
+ }
+ else
+ hn = new Node(MOVED, ht, null, null);
+ setTabAt(nextTab, i + n, hn);
setTabAt(tab, i, fwd);
+ advance = true;
}
} finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
- }
+ t.release(0);
}
- if (!validated)
- continue;
- }
- else {
- if (buffer == null) // initialize buffer for revisits
- buffer = new int[TRANSFER_BUFFER_SIZE];
- if (bin < 0 && bufferIndex > 0) {
- int j = buffer[--bufferIndex];
- buffer[bufferIndex] = i;
- i = j; // swap with another bin
- continue;
- }
- if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
- f.tryAwaitLock(tab, i);
- continue; // no other options -- block
- }
- if (rev == null) // initialize reverse-forwarder
- rev = new Node(MOVED, tab, null, null);
- if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
- continue; // recheck before adding to list
- buffer[nbuffered++] = i;
- setTabAt(nextTab, i, rev); // install place-holders
- setTabAt(nextTab, i + n, rev);
- }
-
- if (bin > 0)
- i = --bin;
- else if (buffer != null && nbuffered > 0) {
- bin = -1;
- i = buffer[bufferIndex = --nbuffered];
}
else
- return nextTab;
+ advance = true; // already processed
}
}
- /**
- * Splits a normal bin with list headed by e into lo and hi parts;
- * installs in given table.
- */
- private static void splitBin(Node[] nextTab, int i, Node e) {
- int bit = nextTab.length >>> 1; // bit to split on
- int runBit = e.hash & bit;
- Node lastRun = e, lo = null, hi = null;
- for (Node p = e.next; p != null; p = p.next) {
- int b = p.hash & bit;
- if (b != runBit) {
- runBit = b;
- lastRun = p;
+ /* ---------------- Counter support -------------- */
+
+ final long sumCount() {
+ CounterCell[] as = counterCells; CounterCell a;
+ long sum = baseCount;
+ if (as != null) {
+ for (int i = 0; i < as.length; ++i) {
+ if ((a = as[i]) != null)
+ sum += a.value;
}
}
- if (runBit == 0)
- lo = lastRun;
- else
- hi = lastRun;
- for (Node p = e; p != lastRun; p = p.next) {
- int ph = p.hash & HASH_BITS;
- Object pk = p.key, pv = p.val;
- if ((ph & bit) == 0)
- lo = new Node(ph, pk, pv, lo);
- else
- hi = new Node(ph, pk, pv, hi);
- }
- setTabAt(nextTab, i, lo);
- setTabAt(nextTab, i + bit, hi);
+ return sum;
}
- /**
- * Splits a tree bin into lo and hi parts; installs in given table.
- */
- private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
- int bit = nextTab.length >>> 1;
- TreeBin lt = new TreeBin();
- TreeBin ht = new TreeBin();
- int lc = 0, hc = 0;
- for (Node e = t.first; e != null; e = e.next) {
- int h = e.hash & HASH_BITS;
- Object k = e.key, v = e.val;
- if ((h & bit) == 0) {
- ++lc;
- lt.putTreeNode(h, k, v);
- }
- else {
- ++hc;
- ht.putTreeNode(h, k, v);
- }
- }
- Node ln, hn; // throw away trees if too small
- if (lc <= (TREE_THRESHOLD >>> 1)) {
- ln = null;
- for (Node p = lt.first; p != null; p = p.next)
- ln = new Node(p.hash, p.key, p.val, ln);
- }
- else
- ln = new Node(MOVED, lt, null, null);
- setTabAt(nextTab, i, ln);
- if (hc <= (TREE_THRESHOLD >>> 1)) {
- hn = null;
- for (Node p = ht.first; p != null; p = p.next)
- hn = new Node(p.hash, p.key, p.val, hn);
+ // See LongAdder version for explanation
+ private final void fullAddCount(long x, CounterHashCode hc,
+ boolean wasUncontended) {
+ int h;
+ if (hc == null) {
+ hc = new CounterHashCode();
+ int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
+ h = hc.code = (s == 0) ? 1 : s; // Avoid zero
+ threadCounterHashCode.set(hc);
}
else
- hn = new Node(MOVED, ht, null, null);
- setTabAt(nextTab, i + bit, hn);
- }
-
- /**
- * Implementation for clear. Steps through each bin, removing all
- * nodes.
- */
- private final void internalClear() {
- long delta = 0L; // negative number of deletions
- int i = 0;
- Node[] tab = table;
- while (tab != null && i < tab.length) {
- int fh; Object fk;
- Node f = tabAt(tab, i);
- if (f == null)
- ++i;
- else if ((fh = f.hash) == MOVED) {
- if ((fk = f.key) instanceof TreeBin) {
- TreeBin t = (TreeBin)fk;
- t.acquire(0);
- try {
- if (tabAt(tab, i) == f) {
- for (Node p = t.first; p != null; p = p.next) {
- if (p.val != null) { // (currently always true)
- p.val = null;
- --delta;
+ h = hc.code;
+ boolean collide = false; // True if last slot nonempty
+ for (;;) {
+ CounterCell[] as; CounterCell a; int n; long v;
+ if ((as = counterCells) != null && (n = as.length) > 0) {
+ if ((a = as[(n - 1) & h]) == null) {
+ if (counterBusy == 0) { // Try to attach new Cell
+ CounterCell r = new CounterCell(x); // Optimistic create
+ if (counterBusy == 0 &&
+ U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
+ boolean created = false;
+ try { // Recheck under lock
+ CounterCell[] rs; int m, j;
+ if ((rs = counterCells) != null &&
+ (m = rs.length) > 0 &&
+ rs[j = (m - 1) & h] == null) {
+ rs[j] = r;
+ created = true;
}
+ } finally {
+ counterBusy = 0;
}
- t.first = null;
- t.root = null;
- ++i;
+ if (created)
+ break;
+ continue; // Slot is now non-empty
}
- } finally {
- t.release(0);
}
+ collide = false;
}
- else
- tab = (Node[])fk;
- }
- else if ((fh & LOCKED) != 0) {
- counter.add(delta); // opportunistically update count
- delta = 0L;
- f.tryAwaitLock(tab, i);
- }
- else if (f.casHash(fh, fh | LOCKED)) {
- try {
- if (tabAt(tab, i) == f) {
- for (Node e = f; e != null; e = e.next) {
- if (e.val != null) { // (currently always true)
- e.val = null;
- --delta;
- }
+ else if (!wasUncontended) // CAS already known to fail
+ wasUncontended = true; // Continue after rehash
+ else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
+ break;
+ else if (counterCells != as || n >= NCPU)
+ collide = false; // At max size or stale
+ else if (!collide)
+ collide = true;
+ else if (counterBusy == 0 &&
+ U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
+ try {
+ if (counterCells == as) {// Expand table unless stale
+ CounterCell[] rs = new CounterCell[n << 1];
+ for (int i = 0; i < n; ++i)
+ rs[i] = as[i];
+ counterCells = rs;
}
- setTabAt(tab, i, null);
- ++i;
+ } finally {
+ counterBusy = 0;
}
- } finally {
- if (!f.casHash(fh | LOCKED, fh)) {
- f.hash = fh;
- synchronized (f) { f.notifyAll(); };
+ collide = false;
+ continue; // Retry with expanded table
+ }
+ h ^= h << 13; // Rehash
+ h ^= h >>> 17;
+ h ^= h << 5;
+ }
+ else if (counterBusy == 0 && counterCells == as &&
+ U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
+ boolean init = false;
+ try { // Initialize table
+ if (counterCells == as) {
+ CounterCell[] rs = new CounterCell[2];
+ rs[h & 1] = new CounterCell(x);
+ counterCells = rs;
+ init = true;
}
+ } finally {
+ counterBusy = 0;
}
+ if (init)
+ break;
}
+ else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
+ break; // Fall back on using base
}
- if (delta != 0)
- counter.add(delta);
+ hc.code = h; // Record index for next time
}
/* ----------------Table Traversal -------------- */
@@ -2448,14 +2260,15 @@ public class ConcurrentHashMapV8
* across threads, iteration terminates if a bounds checks fails
* for a table read.
*
- * This class extends ForkJoinTask to streamline parallel
- * iteration in bulk operations (see BulkTask). This adds only an
- * int of space overhead, which is close enough to negligible in
- * cases where it is not needed to not worry about it. Because
- * ForkJoinTask is Serializable, but iterators need not be, we
- * need to add warning suppressions.
+ * This class extends CountedCompleter to streamline parallel
+ * iteration in bulk operations. This adds only a few fields of
+ * space overhead, which is small enough in cases where it is not
+ * needed to not worry about it. Because CountedCompleter is
+ * Serializable, but iterators need not be, we need to add warning
+ * suppressions.
*/
- @SuppressWarnings("serial") static class Traverser extends ForkJoinTask {
+ @SuppressWarnings("serial") static class Traverser
+ extends CountedCompleter {
final ConcurrentHashMapV8 map;
Node next; // the next entry to use
Object nextKey; // cached key field of next
@@ -2465,24 +2278,28 @@ public class ConcurrentHashMapV8
int baseIndex; // current index of initial table
int baseLimit; // index bound for initial table
int baseSize; // initial table size
+ int batch; // split control
/** Creates iterator for all entries in the table. */
Traverser(ConcurrentHashMapV8 map) {
this.map = map;
}
- /** Creates iterator for split() methods */
- Traverser(Traverser it) {
- ConcurrentHashMapV8 m; Node[] t;
- if ((m = this.map = it.map) == null)
- t = null;
- else if ((t = it.tab) == null && // force parent tab initialization
- (t = it.tab = m.table) != null)
- it.baseLimit = it.baseSize = t.length;
- this.tab = t;
- this.baseSize = it.baseSize;
- it.baseLimit = this.index = this.baseIndex =
- ((this.baseLimit = it.baseLimit) + it.baseIndex + 1) >>> 1;
+ /** Creates iterator for split() methods and task constructors */
+ Traverser(ConcurrentHashMapV8 map, Traverser it, int batch) {
+ super(it);
+ this.batch = batch;
+ if ((this.map = map) != null && it != null) { // split parent
+ Node[] t;
+ if ((t = it.tab) == null &&
+ (t = it.tab = map.table) != null)
+ it.baseLimit = it.baseSize = t.length;
+ this.tab = t;
+ this.baseSize = it.baseSize;
+ int hi = this.baseLimit = it.baseLimit;
+ it.baseLimit = this.index = this.baseIndex =
+ (hi + it.baseIndex + 1) >>> 1;
+ }
}
/**
@@ -2507,7 +2324,7 @@ public class ConcurrentHashMapV8
if ((b = baseIndex) >= baseLimit ||
(i = index) < 0 || i >= n)
break outer;
- if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
+ if ((e = tabAt(t, i)) != null && e.hash < 0) {
if ((ek = e.key) instanceof TreeBin)
e = ((TreeBin)ek).first;
else {
@@ -2535,9 +2352,39 @@ public class ConcurrentHashMapV8
}
public final boolean hasMoreElements() { return hasNext(); }
- public final void setRawResult(Object x) { }
- public R getRawResult() { return null; }
- public boolean exec() { return true; }
+
+ public void compute() { } // default no-op CountedCompleter body
+
+ /**
+ * Returns a batch value > 0 if this task should (and must) be
+ * split, if so, adding to pending count, and in any case
+ * updating batch value. The initial batch value is approx
+ * exp2 of the number of times (minus one) to split task by
+ * two before executing leaf action. This value is faster to
+ * compute and more convenient to use as a guide to splitting
+ * than is the depth, since it is used while dividing by two
+ * anyway.
+ */
+ final int preSplit() {
+ ConcurrentHashMapV8 m; int b; Node[] t; ForkJoinPool pool;
+ if ((b = batch) < 0 && (m = map) != null) { // force initialization
+ if ((t = tab) == null && (t = tab = m.table) != null)
+ baseLimit = baseSize = t.length;
+ if (t != null) {
+ long n = m.sumCount();
+ int par = ((pool = getPool()) == null) ?
+ ForkJoinPool.getCommonPoolParallelism() :
+ pool.getParallelism();
+ int sp = par << 3; // slack of 8
+ b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
+ }
+ }
+ b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
+ if ((batch = b) > 0)
+ addToPendingCount(1);
+ return b;
+ }
+
}
/* ---------------- Public operations -------------- */
@@ -2546,7 +2393,6 @@ public class ConcurrentHashMapV8
* Creates a new, empty map with the default initial table size (16).
*/
public ConcurrentHashMapV8() {
- this.counter = new LongAdder();
}
/**
@@ -2565,7 +2411,6 @@ public class ConcurrentHashMapV8
int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
MAXIMUM_CAPACITY :
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
- this.counter = new LongAdder();
this.sizeCtl = cap;
}
@@ -2575,7 +2420,6 @@ public class ConcurrentHashMapV8
* @param m the map
*/
public ConcurrentHashMapV8(Map m) {
- this.counter = new LongAdder();
this.sizeCtl = DEFAULT_CAPACITY;
internalPutAll(m);
}
@@ -2626,7 +2470,6 @@ public class ConcurrentHashMapV8
long size = (long)(1.0 + (long)initialCapacity / loadFactor);
int cap = (size >= (long)MAXIMUM_CAPACITY) ?
MAXIMUM_CAPACITY : tableSizeFor((int)size);
- this.counter = new LongAdder();
this.sizeCtl = cap;
}
@@ -2652,22 +2495,22 @@ public class ConcurrentHashMapV8
* @return the new set
*/
public static KeySetView newKeySet(int initialCapacity) {
- return new KeySetView(new ConcurrentHashMapV8(initialCapacity),
- Boolean.TRUE);
+ return new KeySetView
+ (new ConcurrentHashMapV8(initialCapacity), Boolean.TRUE);
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
- return counter.sum() <= 0L; // ignore transient negative values
+ return sumCount() <= 0L; // ignore transient negative values
}
/**
* {@inheritDoc}
*/
public int size() {
- long n = counter.sum();
+ long n = sumCount();
return ((n < 0L) ? 0 :
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
(int)n);
@@ -2677,13 +2520,13 @@ public class ConcurrentHashMapV8
* Returns the number of mappings. This method should be used
* instead of {@link #size} because a ConcurrentHashMapV8 may
* contain more mappings than can be represented as an int. The
- * value returned is a snapshot; the actual count may differ if
- * there are ongoing concurrent insertions or removals.
+ * value returned is an estimate; the actual count may differ if
+ * there are concurrent insertions or removals.
*
* @return the number of mappings
*/
public long mappingCount() {
- long n = counter.sum();
+ long n = sumCount();
return (n < 0L) ? 0L : n; // ignore transient negative values
}
@@ -2698,10 +2541,8 @@ public class ConcurrentHashMapV8
*
* @throws NullPointerException if the specified key is null
*/
- @SuppressWarnings("unchecked") public V get(Object key) {
- if (key == null)
- throw new NullPointerException();
- return (V)internalGet(key);
+ public V get(Object key) {
+ return internalGet(key);
}
/**
@@ -2714,11 +2555,9 @@ public class ConcurrentHashMapV8
* @return the mapping for the key, if present; else the defaultValue
* @throws NullPointerException if the specified key is null
*/
- @SuppressWarnings("unchecked") public V getValueOrDefault(Object key, V defaultValue) {
- if (key == null)
- throw new NullPointerException();
- V v = (V) internalGet(key);
- return v == null ? defaultValue : v;
+ public V getValueOrDefault(Object key, V defaultValue) {
+ V v;
+ return (v = internalGet(key)) == null ? defaultValue : v;
}
/**
@@ -2731,8 +2570,6 @@ public class ConcurrentHashMapV8
* @throws NullPointerException if the specified key is null
*/
public boolean containsKey(Object key) {
- if (key == null)
- throw new NullPointerException();
return internalGet(key) != null;
}
@@ -2781,7 +2618,7 @@ public class ConcurrentHashMapV8
* Maps the specified key to the specified value in this table.
* Neither the key nor the value can be null.
*
- * The value can be retrieved by calling the {@code get} method
+ *
The value can be retrieved by calling the {@code get} method
* with a key that is equal to the original key.
*
* @param key key with which the specified value is to be associated
@@ -2790,10 +2627,8 @@ public class ConcurrentHashMapV8
* {@code null} if there was no mapping for {@code key}
* @throws NullPointerException if the specified key or value is null
*/
- @SuppressWarnings("unchecked") public V put(K key, V value) {
- if (key == null || value == null)
- throw new NullPointerException();
- return (V)internalPut(key, value);
+ public V put(K key, V value) {
+ return internalPut(key, value, false);
}
/**
@@ -2803,10 +2638,8 @@ public class ConcurrentHashMapV8
* or {@code null} if there was no mapping for the key
* @throws NullPointerException if the specified key or value is null
*/
- @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
- if (key == null || value == null)
- throw new NullPointerException();
- return (V)internalPutIfAbsent(key, value);
+ public V putIfAbsent(K key, V value) {
+ return internalPut(key, value, true);
}
/**
@@ -2859,11 +2692,9 @@ public class ConcurrentHashMapV8
* @throws RuntimeException or Error if the mappingFunction does so,
* in which case the mapping is left unestablished
*/
- @SuppressWarnings("unchecked") public V computeIfAbsent
+ public V computeIfAbsent
(K key, Fun mappingFunction) {
- if (key == null || mappingFunction == null)
- throw new NullPointerException();
- return (V)internalComputeIfAbsent(key, mappingFunction);
+ return internalComputeIfAbsent(key, mappingFunction);
}
/**
@@ -2900,11 +2731,9 @@ public class ConcurrentHashMapV8
* @throws RuntimeException or Error if the remappingFunction does so,
* in which case the mapping is unchanged
*/
- @SuppressWarnings("unchecked") public V computeIfPresent
+ public V computeIfPresent
(K key, BiFun remappingFunction) {
- if (key == null || remappingFunction == null)
- throw new NullPointerException();
- return (V)internalCompute(key, true, remappingFunction);
+ return internalCompute(key, true, remappingFunction);
}
/**
@@ -2947,11 +2776,9 @@ public class ConcurrentHashMapV8
* @throws RuntimeException or Error if the remappingFunction does so,
* in which case the mapping is unchanged
*/
- @SuppressWarnings("unchecked") public V compute
+ public V compute
(K key, BiFun remappingFunction) {
- if (key == null || remappingFunction == null)
- throw new NullPointerException();
- return (V)internalCompute(key, false, remappingFunction);
+ return internalCompute(key, false, remappingFunction);
}
/**
@@ -2979,11 +2806,10 @@ public class ConcurrentHashMapV8
* so the computation should be short and simple, and must not
* attempt to update any other mappings of this Map.
*/
- @SuppressWarnings("unchecked") public V merge
- (K key, V value, BiFun remappingFunction) {
- if (key == null || value == null || remappingFunction == null)
- throw new NullPointerException();
- return (V)internalMerge(key, value, remappingFunction);
+ public V merge
+ (K key, V value,
+ BiFun remappingFunction) {
+ return internalMerge(key, value, remappingFunction);
}
/**
@@ -2995,10 +2821,8 @@ public class ConcurrentHashMapV8
* {@code null} if there was no mapping for {@code key}
* @throws NullPointerException if the specified key is null
*/
- @SuppressWarnings("unchecked") public V remove(Object key) {
- if (key == null)
- throw new NullPointerException();
- return (V)internalReplace(key, null, null);
+ public V remove(Object key) {
+ return internalReplace(key, null, null);
}
/**
@@ -3007,11 +2831,7 @@ public class ConcurrentHashMapV8
* @throws NullPointerException if the specified key is null
*/
public boolean remove(Object key, Object value) {
- if (key == null)
- throw new NullPointerException();
- if (value == null)
- return false;
- return internalReplace(key, null, value) != null;
+ return value != null && internalReplace(key, null, value) != null;
}
/**
@@ -3032,10 +2852,10 @@ public class ConcurrentHashMapV8
* or {@code null} if there was no mapping for the key
* @throws NullPointerException if the specified key or value is null
*/
- @SuppressWarnings("unchecked") public V replace(K key, V value) {
+ public V replace(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
- return (V)internalReplace(key, value, null);
+ return internalReplace(key, value, null);
}
/**
@@ -3078,22 +2898,11 @@ public class ConcurrentHashMapV8
/**
* Returns a {@link Collection} view of the values contained in this map.
* The collection is backed by the map, so changes to the map are
- * reflected in the collection, and vice-versa. The collection
- * supports element removal, which removes the corresponding
- * mapping from this map, via the {@code Iterator.remove},
- * {@code Collection.remove}, {@code removeAll},
- * {@code retainAll}, and {@code clear} operations. It does not
- * support the {@code add} or {@code addAll} operations.
- *
- * The view's {@code iterator} is a "weakly consistent" iterator
- * that will never throw {@link ConcurrentModificationException},
- * and guarantees to traverse elements as they existed upon
- * construction of the iterator, and may (but is not guaranteed to)
- * reflect any modifications subsequent to construction.
+ * reflected in the collection, and vice-versa.
*/
- public Collection values() {
- Values vs = values;
- return (vs != null) ? vs : (values = new Values(this));
+ public ValuesView values() {
+ ValuesView vs = values;
+ return (vs != null) ? vs : (values = new ValuesView(this));
}
/**
@@ -3113,8 +2922,8 @@ public class ConcurrentHashMapV8
* reflect any modifications subsequent to construction.
*/
public Set> entrySet() {
- EntrySet es = entrySet;
- return (es != null) ? es : (entrySet = new EntrySet(this));
+ EntrySetView es = entrySet;
+ return (es != null) ? es : (entrySet = new EntrySetView(this));
}
/**
@@ -3247,16 +3056,17 @@ public class ConcurrentHashMapV8
/* ----------------Iterators -------------- */
- @SuppressWarnings("serial") static final class KeyIterator extends Traverser
+ @SuppressWarnings("serial") static final class KeyIterator
+ extends Traverser
implements Spliterator, Enumeration {
KeyIterator(ConcurrentHashMapV8 map) { super(map); }
- KeyIterator(Traverser it) {
- super(it);
+ KeyIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public KeyIterator split() {
if (nextKey != null)
throw new IllegalStateException();
- return new KeyIterator(this);
+ return new KeyIterator(map, this);
}
@SuppressWarnings("unchecked") public final K next() {
if (nextVal == null && advance() == null)
@@ -3269,16 +3079,17 @@ public class ConcurrentHashMapV8
public final K nextElement() { return next(); }
}
- @SuppressWarnings("serial") static final class ValueIterator extends Traverser
+ @SuppressWarnings("serial") static final class ValueIterator
+ extends Traverser
implements Spliterator, Enumeration {
ValueIterator(ConcurrentHashMapV8 map) { super(map); }
- ValueIterator(Traverser it) {
- super(it);
+ ValueIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public ValueIterator split() {
if (nextKey != null)
throw new IllegalStateException();
- return new ValueIterator(this);
+ return new ValueIterator(map, this);
}
@SuppressWarnings("unchecked") public final V next() {
@@ -3292,16 +3103,17 @@ public class ConcurrentHashMapV8
public final V nextElement() { return next(); }
}
- @SuppressWarnings("serial") static final class EntryIterator extends Traverser
+ @SuppressWarnings("serial") static final class EntryIterator
+ extends Traverser
implements Spliterator> {
EntryIterator(ConcurrentHashMapV8 map) { super(map); }
- EntryIterator(Traverser it) {
- super(it);
+ EntryIterator(ConcurrentHashMapV8 map, Traverser it) {
+ super(map, it, -1);
}
public EntryIterator split() {
if (nextKey != null)
throw new IllegalStateException();
- return new EntryIterator(this);
+ return new EntryIterator(map, this);
}
@SuppressWarnings("unchecked") public final Map.Entry next() {
@@ -3357,197 +3169,12 @@ public class ConcurrentHashMapV8
}
}
- /* ----------------Views -------------- */
-
/**
- * Base class for views.
+ * Returns exportable snapshot entry for the given key and value
+ * when write-through can't or shouldn't be used.
*/
- static abstract class CHMView {
- final ConcurrentHashMapV8 map;
- CHMView(ConcurrentHashMapV8 map) { this.map = map; }
- public final int size() { return map.size(); }
- public final boolean isEmpty() { return map.isEmpty(); }
- public final void clear() { map.clear(); }
-
- // implementations below rely on concrete classes supplying these
- abstract public Iterator iterator();
- abstract public boolean contains(Object o);
- abstract public boolean remove(Object o);
-
- private static final String oomeMsg = "Required array size too large";
-
- public final Object[] toArray() {
- long sz = map.mappingCount();
- if (sz > (long)(MAX_ARRAY_SIZE))
- throw new OutOfMemoryError(oomeMsg);
- int n = (int)sz;
- Object[] r = new Object[n];
- int i = 0;
- Iterator it = iterator();
- while (it.hasNext()) {
- if (i == n) {
- if (n >= MAX_ARRAY_SIZE)
- throw new OutOfMemoryError(oomeMsg);
- if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
- n = MAX_ARRAY_SIZE;
- else
- n += (n >>> 1) + 1;
- r = Arrays.copyOf(r, n);
- }
- r[i++] = it.next();
- }
- return (i == n) ? r : Arrays.copyOf(r, i);
- }
-
- @SuppressWarnings("unchecked") public final T[] toArray(T[] a) {
- long sz = map.mappingCount();
- if (sz > (long)(MAX_ARRAY_SIZE))
- throw new OutOfMemoryError(oomeMsg);
- int m = (int)sz;
- T[] r = (a.length >= m) ? a :
- (T[])java.lang.reflect.Array
- .newInstance(a.getClass().getComponentType(), m);
- int n = r.length;
- int i = 0;
- Iterator it = iterator();
- while (it.hasNext()) {
- if (i == n) {
- if (n >= MAX_ARRAY_SIZE)
- throw new OutOfMemoryError(oomeMsg);
- if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
- n = MAX_ARRAY_SIZE;
- else
- n += (n >>> 1) + 1;
- r = Arrays.copyOf(r, n);
- }
- r[i++] = (T)it.next();
- }
- if (a == r && i < n) {
- r[i] = null; // null-terminate
- return r;
- }
- return (i == n) ? r : Arrays.copyOf(r, i);
- }
-
- public final int hashCode() {
- int h = 0;
- for (Iterator it = iterator(); it.hasNext();)
- h += it.next().hashCode();
- return h;
- }
-
- public final String toString() {
- StringBuilder sb = new StringBuilder();
- sb.append('[');
- Iterator it = iterator();
- if (it.hasNext()) {
- for (;;) {
- Object e = it.next();
- sb.append(e == this ? "(this Collection)" : e);
- if (!it.hasNext())
- break;
- sb.append(',').append(' ');
- }
- }
- return sb.append(']').toString();
- }
-
- public final boolean containsAll(Collection c) {
- if (c != this) {
- for (Iterator it = c.iterator(); it.hasNext();) {
- Object e = it.next();
- if (e == null || !contains(e))
- return false;
- }
- }
- return true;
- }
-
- public final boolean removeAll(Collection c) {
- boolean modified = false;
- for (Iterator it = iterator(); it.hasNext();) {
- if (c.contains(it.next())) {
- it.remove();
- modified = true;
- }
- }
- return modified;
- }
-
- public final boolean retainAll(Collection c) {
- boolean modified = false;
- for (Iterator it = iterator(); it.hasNext();) {
- if (!c.contains(it.next())) {
- it.remove();
- modified = true;
- }
- }
- return modified;
- }
-
- }
-
- static final class Values extends CHMView
- implements Collection {
- Values(ConcurrentHashMapV8 map) { super(map); }
- public final boolean contains(Object o) { return map.containsValue(o); }
- public final boolean remove(Object o) {
- if (o != null) {
- Iterator it = new ValueIterator(map);
- while (it.hasNext()) {
- if (o.equals(it.next())) {
- it.remove();
- return true;
- }
- }
- }
- return false;
- }
- public final Iterator iterator() {
- return new ValueIterator(map);
- }
- public final boolean add(V e) {
- throw new UnsupportedOperationException();
- }
- public final boolean addAll(Collection c) {
- throw new UnsupportedOperationException();
- }
-
- }
-
- static final class EntrySet extends CHMView
- implements Set> {
- EntrySet(ConcurrentHashMapV8 map) { super(map); }
- public final boolean contains(Object o) {
- Object k, v, r; Map.Entry e;
- return ((o instanceof Map.Entry) &&
- (k = (e = (Map.Entry)o).getKey()) != null &&
- (r = map.get(k)) != null &&
- (v = e.getValue()) != null &&
- (v == r || v.equals(r)));
- }
- public final boolean remove(Object o) {
- Object k, v; Map.Entry e;
- return ((o instanceof Map.Entry) &&
- (k = (e = (Map.Entry)o).getKey()) != null &&
- (v = e.getValue()) != null &&
- map.remove(k, v));
- }
- public final Iterator> iterator() {
- return new EntryIterator(map);
- }
- public final boolean add(Entry e) {
- throw new UnsupportedOperationException();
- }
- public final boolean addAll(Collection> c) {
- throw new UnsupportedOperationException();
- }
- public boolean equals(Object o) {
- Set c;
- return ((o instanceof Set) &&
- ((c = (Set)o) == this ||
- (containsAll(c) && c.containsAll(this))));
- }
+ static AbstractMap.SimpleEntry entryFor(K k, V v) {
+ return new AbstractMap.SimpleEntry(k, v);
}
/* ---------------- Serialization Support -------------- */
@@ -3571,7 +3198,8 @@ public class ConcurrentHashMapV8
* for each key-value mapping, followed by a null pair.
* The key-value mappings are emitted in no particular order.
*/
- @SuppressWarnings("unchecked") private void writeObject(java.io.ObjectOutputStream s)
+ @SuppressWarnings("unchecked") private void writeObject
+ (java.io.ObjectOutputStream s)
throws java.io.IOException {
if (segments == null) { // for serialization compatibility
segments = (Segment[])
@@ -3595,12 +3223,11 @@ public class ConcurrentHashMapV8
* Reconstitutes the instance from a stream (that is, deserializes it).
* @param s the stream
*/
- @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s)
+ @SuppressWarnings("unchecked") private void readObject
+ (java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
this.segments = null; // unneeded
- // initialize transient final field
- UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
// Create all nodes, then place in table once size is known
long size = 0L;
@@ -3628,7 +3255,7 @@ public class ConcurrentHashMapV8
int sc = sizeCtl;
boolean collide = false;
if (n > sc &&
- UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
+ U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if (table == null) {
init = true;
@@ -3644,7 +3271,7 @@ public class ConcurrentHashMapV8
p = next;
}
table = tab;
- counter.add(size);
+ addCount(size, -1);
sc = n - (n >>> 2);
}
} finally {
@@ -3666,14 +3293,13 @@ public class ConcurrentHashMapV8
}
if (!init) { // Can only happen if unsafely published.
while (p != null) {
- internalPut(p.key, p.val);
+ internalPut((K)p.key, (V)p.val, false);
p = p.next;
}
}
}
}
-
// -------------------------------------------------------
// Sams
@@ -4220,6 +3846,697 @@ public class ConcurrentHashMapV8
(this, transformer, basis, reducer).invoke();
}
+ /* ----------------Views -------------- */
+
+ /**
+ * Base class for views.
+ */
+ static abstract class CHMView {
+ final ConcurrentHashMapV8 map;
+ CHMView(ConcurrentHashMapV8 map) { this.map = map; }
+
+ /**
+ * Returns the map backing this view.
+ *
+ * @return the map backing this view
+ */
+ public ConcurrentHashMapV8 getMap() { return map; }
+
+ public final int size() { return map.size(); }
+ public final boolean isEmpty() { return map.isEmpty(); }
+ public final void clear() { map.clear(); }
+
+ // implementations below rely on concrete classes supplying these
+ abstract public Iterator iterator();
+ abstract public boolean contains(Object o);
+ abstract public boolean remove(Object o);
+
+ private static final String oomeMsg = "Required array size too large";
+
+ public final Object[] toArray() {
+ long sz = map.mappingCount();
+ if (sz > (long)(MAX_ARRAY_SIZE))
+ throw new OutOfMemoryError(oomeMsg);
+ int n = (int)sz;
+ Object[] r = new Object[n];
+ int i = 0;
+ Iterator it = iterator();
+ while (it.hasNext()) {
+ if (i == n) {
+ if (n >= MAX_ARRAY_SIZE)
+ throw new OutOfMemoryError(oomeMsg);
+ if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
+ n = MAX_ARRAY_SIZE;
+ else
+ n += (n >>> 1) + 1;
+ r = Arrays.copyOf(r, n);
+ }
+ r[i++] = it.next();
+ }
+ return (i == n) ? r : Arrays.copyOf(r, i);
+ }
+
+ @SuppressWarnings("unchecked") public final T[] toArray(T[] a) {
+ long sz = map.mappingCount();
+ if (sz > (long)(MAX_ARRAY_SIZE))
+ throw new OutOfMemoryError(oomeMsg);
+ int m = (int)sz;
+ T[] r = (a.length >= m) ? a :
+ (T[])java.lang.reflect.Array
+ .newInstance(a.getClass().getComponentType(), m);
+ int n = r.length;
+ int i = 0;
+ Iterator it = iterator();
+ while (it.hasNext()) {
+ if (i == n) {
+ if (n >= MAX_ARRAY_SIZE)
+ throw new OutOfMemoryError(oomeMsg);
+ if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
+ n = MAX_ARRAY_SIZE;
+ else
+ n += (n >>> 1) + 1;
+ r = Arrays.copyOf(r, n);
+ }
+ r[i++] = (T)it.next();
+ }
+ if (a == r && i < n) {
+ r[i] = null; // null-terminate
+ return r;
+ }
+ return (i == n) ? r : Arrays.copyOf(r, i);
+ }
+
+ public final int hashCode() {
+ int h = 0;
+ for (Iterator it = iterator(); it.hasNext();)
+ h += it.next().hashCode();
+ return h;
+ }
+
+ public final String toString() {
+ StringBuilder sb = new StringBuilder();
+ sb.append('[');
+ Iterator it = iterator();
+ if (it.hasNext()) {
+ for (;;) {
+ Object e = it.next();
+ sb.append(e == this ? "(this Collection)" : e);
+ if (!it.hasNext())
+ break;
+ sb.append(',').append(' ');
+ }
+ }
+ return sb.append(']').toString();
+ }
+
+ public final boolean containsAll(Collection c) {
+ if (c != this) {
+ for (Iterator it = c.iterator(); it.hasNext();) {
+ Object e = it.next();
+ if (e == null || !contains(e))
+ return false;
+ }
+ }
+ return true;
+ }
+
+ public final boolean removeAll(Collection c) {
+ boolean modified = false;
+ for (Iterator it = iterator(); it.hasNext();) {
+ if (c.contains(it.next())) {
+ it.remove();
+ modified = true;
+ }
+ }
+ return modified;
+ }
+
+ public final boolean retainAll(Collection c) {
+ boolean modified = false;
+ for (Iterator it = iterator(); it.hasNext();) {
+ if (!c.contains(it.next())) {
+ it.remove();
+ modified = true;
+ }
+ }
+ return modified;
+ }
+
+ }
+
+ /**
+ * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in
+ * which additions may optionally be enabled by mapping to a
+ * common value. This class cannot be directly instantiated. See
+ * {@link #keySet}, {@link #keySet(Object)}, {@link #newKeySet()},
+ * {@link #newKeySet(int)}.
+ */
+ public static class KeySetView extends CHMView
+ implements Set, java.io.Serializable {
+ private static final long serialVersionUID = 7249069246763182397L;
+ private final V value;
+ KeySetView(ConcurrentHashMapV8 map, V value) { // non-public
+ super(map);
+ this.value = value;
+ }
+
+ /**
+ * Returns the default mapped value for additions,
+ * or {@code null} if additions are not supported.
+ *
+ * @return the default mapped value for additions, or {@code null}
+ * if not supported.
+ */
+ public V getMappedValue() { return value; }
+
+ // implement Set API
+
+ public boolean contains(Object o) { return map.containsKey(o); }
+ public boolean remove(Object o) { return map.remove(o) != null; }
+
+ /**
+ * Returns a "weakly consistent" iterator that will never
+ * throw {@link ConcurrentModificationException}, and
+ * guarantees to traverse elements as they existed upon
+ * construction of the iterator, and may (but is not
+ * guaranteed to) reflect any modifications subsequent to
+ * construction.
+ *
+ * @return an iterator over the keys of this map
+ */
+ public Iterator iterator() { return new KeyIterator(map); }
+ public boolean add(K e) {
+ V v;
+ if ((v = value) == null)
+ throw new UnsupportedOperationException();
+ if (e == null)
+ throw new NullPointerException();
+ return map.internalPut(e, v, true) == null;
+ }
+ public boolean addAll(Collection c) {
+ boolean added = false;
+ V v;
+ if ((v = value) == null)
+ throw new UnsupportedOperationException();
+ for (K e : c) {
+ if (e == null)
+ throw new NullPointerException();
+ if (map.internalPut(e, v, true) == null)
+ added = true;
+ }
+ return added;
+ }
+ public boolean equals(Object o) {
+ Set c;
+ return ((o instanceof Set) &&
+ ((c = (Set)o) == this ||
+ (containsAll(c) && c.containsAll(this))));
+ }
+
+ /**
+ * Performs the given action for each key.
+ *
+ * @param action the action
+ */
+ public void forEach(Action action) {
+ ForkJoinTasks.forEachKey
+ (map, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each key.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ * @param action the action
+ */
+ public void forEach(Fun transformer,
+ Action action) {
+ ForkJoinTasks.forEachKey
+ (map, transformer, action).invoke();
+ }
+
+ /**
+ * Returns a non-null result from applying the given search
+ * function on each key, or null if none. Upon success,
+ * further element processing is suppressed and the results of
+ * any other parallel invocations of the search function are
+ * ignored.
+ *
+ * @param searchFunction a function returning a non-null
+ * result on success, else null
+ * @return a non-null result from applying the given search
+ * function on each key, or null if none
+ */
+ public U search(Fun searchFunction) {
+ return ForkJoinTasks.searchKeys
+ (map, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all keys using the given
+ * reducer to combine values, or null if none.
+ *
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating all keys using the given
+ * reducer to combine values, or null if none
+ */
+ public K reduce(BiFun reducer) {
+ return ForkJoinTasks.reduceKeys
+ (map, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all keys using the given reducer to combine values, and
+ * the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all keys
+ */
+ public double reduceToDouble(ObjectToDouble transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceKeysToDouble
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all keys using the given reducer to combine values, and
+ * the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all keys
+ */
+ public long reduceToLong(ObjectToLong transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceKeysToLong
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all keys using the given reducer to combine values, and
+ * the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all keys
+ */
+ public int reduceToInt(ObjectToInt transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceKeysToInt
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ }
+
+ /**
+ * A view of a ConcurrentHashMapV8 as a {@link Collection} of
+ * values, in which additions are disabled. This class cannot be
+ * directly instantiated. See {@link #values},
+ *
+ * The view's {@code iterator} is a "weakly consistent" iterator
+ * that will never throw {@link ConcurrentModificationException},
+ * and guarantees to traverse elements as they existed upon
+ * construction of the iterator, and may (but is not guaranteed to)
+ * reflect any modifications subsequent to construction.
+ */
+ public static final class ValuesView extends CHMView
+ implements Collection {
+ ValuesView(ConcurrentHashMapV8 map) { super(map); }
+ public final boolean contains(Object o) { return map.containsValue(o); }
+ public final boolean remove(Object o) {
+ if (o != null) {
+ Iterator it = new ValueIterator(map);
+ while (it.hasNext()) {
+ if (o.equals(it.next())) {
+ it.remove();
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Returns a "weakly consistent" iterator that will never
+ * throw {@link ConcurrentModificationException}, and
+ * guarantees to traverse elements as they existed upon
+ * construction of the iterator, and may (but is not
+ * guaranteed to) reflect any modifications subsequent to
+ * construction.
+ *
+ * @return an iterator over the values of this map
+ */
+ public final Iterator iterator() {
+ return new ValueIterator(map);
+ }
+ public final boolean add(V e) {
+ throw new UnsupportedOperationException();
+ }
+ public final boolean addAll(Collection c) {
+ throw new UnsupportedOperationException();
+ }
+
+ /**
+ * Performs the given action for each value.
+ *
+ * @param action the action
+ */
+ public void forEach(Action action) {
+ ForkJoinTasks.forEachValue
+ (map, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ */
+ public void forEach(Fun transformer,
+ Action action) {
+ ForkJoinTasks.forEachValue
+ (map, transformer, action).invoke();
+ }
+
+ /**
+ * Returns a non-null result from applying the given search
+ * function on each value, or null if none. Upon success,
+ * further element processing is suppressed and the results of
+ * any other parallel invocations of the search function are
+ * ignored.
+ *
+ * @param searchFunction a function returning a non-null
+ * result on success, else null
+ * @return a non-null result from applying the given search
+ * function on each value, or null if none
+ *
+ */
+ public U search(Fun searchFunction) {
+ return ForkJoinTasks.searchValues
+ (map, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all values using the
+ * given reducer to combine values, or null if none.
+ *
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating all values
+ */
+ public V reduce(BiFun reducer) {
+ return ForkJoinTasks.reduceValues
+ (map, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all values using the given reducer to combine values, or
+ * null if none.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case it is not combined).
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all values
+ */
+ public U reduce(Fun transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduceValues
+ (map, transformer, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all values using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all values
+ */
+ public double reduceToDouble(ObjectToDouble transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceValuesToDouble
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all values using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all values
+ */
+ public long reduceToLong(ObjectToLong transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceValuesToLong
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all values using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all values
+ */
+ public int reduceToInt(ObjectToInt transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceValuesToInt
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ }
+
+ /**
+ * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value)
+ * entries. This class cannot be directly instantiated. See
+ * {@link #entrySet}.
+ */
+ public static final class EntrySetView extends CHMView
+ implements Set> {
+ EntrySetView(ConcurrentHashMapV8 map) { super(map); }
+ public final boolean contains(Object o) {
+ Object k, v, r; Map.Entry e;
+ return ((o instanceof Map.Entry) &&
+ (k = (e = (Map.Entry)o).getKey()) != null &&
+ (r = map.get(k)) != null &&
+ (v = e.getValue()) != null &&
+ (v == r || v.equals(r)));
+ }
+ public final boolean remove(Object o) {
+ Object k, v; Map.Entry e;
+ return ((o instanceof Map.Entry) &&
+ (k = (e = (Map.Entry)o).getKey()) != null &&
+ (v = e.getValue()) != null &&
+ map.remove(k, v));
+ }
+
+ /**
+ * Returns a "weakly consistent" iterator that will never
+ * throw {@link ConcurrentModificationException}, and
+ * guarantees to traverse elements as they existed upon
+ * construction of the iterator, and may (but is not
+ * guaranteed to) reflect any modifications subsequent to
+ * construction.
+ *
+ * @return an iterator over the entries of this map
+ */
+ public final Iterator> iterator() {
+ return new EntryIterator(map);
+ }
+
+ public final boolean add(Entry e) {
+ K key = e.getKey();
+ V value = e.getValue();
+ if (key == null || value == null)
+ throw new NullPointerException();
+ return map.internalPut(key, value, false) == null;
+ }
+ public final boolean addAll(Collection> c) {
+ boolean added = false;
+ for (Entry e : c) {
+ if (add(e))
+ added = true;
+ }
+ return added;
+ }
+ public boolean equals(Object o) {
+ Set c;
+ return ((o instanceof Set) &&
+ ((c = (Set)o) == this ||
+ (containsAll(c) && c.containsAll(this))));
+ }
+
+ /**
+ * Performs the given action for each entry.
+ *
+ * @param action the action
+ */
+ public void forEach(Action> action) {
+ ForkJoinTasks.forEachEntry
+ (map, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each entry.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case the action is not applied).
+ * @param action the action
+ */
+ public void forEach(Fun, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEachEntry
+ (map, transformer, action).invoke();
+ }
+
+ /**
+ * Returns a non-null result from applying the given search
+ * function on each entry, or null if none. Upon success,
+ * further element processing is suppressed and the results of
+ * any other parallel invocations of the search function are
+ * ignored.
+ *
+ * @param searchFunction a function returning a non-null
+ * result on success, else null
+ * @return a non-null result from applying the given search
+ * function on each entry, or null if none
+ */
+ public U search(Fun, ? extends U> searchFunction) {
+ return ForkJoinTasks.searchEntries
+ (map, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating all entries using the
+ * given reducer to combine values, or null if none.
+ *
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating all entries
+ */
+ public Map.Entry reduce(BiFun, Map.Entry, ? extends Map.Entry> reducer) {
+ return ForkJoinTasks.reduceEntries
+ (map, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all entries using the given reducer to combine values,
+ * or null if none.
+ *
+ * @param transformer a function returning the transformation
+ * for an element, or null of there is no transformation (in
+ * which case it is not combined).
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all entries
+ */
+ public U reduce(Fun, ? extends U> transformer,
+ BiFun reducer) {
+ return ForkJoinTasks.reduceEntries
+ (map, transformer, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all entries using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all entries
+ */
+ public double reduceToDouble(ObjectToDouble> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceEntriesToDouble
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all entries using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all entries
+ */
+ public long reduceToLong(ObjectToLong> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceEntriesToLong
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all entries using the given reducer to combine values,
+ * and the given basis as an identity value.
+ *
+ * @param transformer a function returning the transformation
+ * for an element
+ * @param basis the identity (initial default value) for the reduction
+ * @param reducer a commutative associative combining function
+ * @return the result of accumulating the given transformation
+ * of all entries
+ */
+ public int reduceToInt(ObjectToInt> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceEntriesToInt
+ (map, transformer, basis, reducer).invoke();
+ }
+
+ }
+
// ---------------------------------------------------------------------
/**
@@ -4246,7 +4563,7 @@ public class ConcurrentHashMapV8
(ConcurrentHashMapV8 map,
BiAction action) {
if (action == null) throw new NullPointerException();
- return new ForEachMappingTask(map, null, -1, null, action);
+ return new ForEachMappingTask(map, null, -1, action);
}
/**
@@ -4267,7 +4584,7 @@ public class ConcurrentHashMapV8
if (transformer == null || action == null)
throw new NullPointerException();
return new ForEachTransformedMappingTask
- (map, null, -1, null, transformer, action);
+ (map, null, -1, transformer, action);
}
/**
@@ -4287,7 +4604,7 @@ public class ConcurrentHashMapV8
BiFun searchFunction) {
if (searchFunction == null) throw new NullPointerException();
return new SearchMappingsTask
- (map, null, -1, null, searchFunction,
+ (map, null, -1, searchFunction,
new AtomicReference());
}
@@ -4396,7 +4713,7 @@ public class ConcurrentHashMapV8
(ConcurrentHashMapV8 map,
Action action) {
if (action == null) throw new NullPointerException();
- return new ForEachKeyTask(map, null, -1, null, action);
+ return new ForEachKeyTask(map, null, -1, action);
}
/**
@@ -4417,7 +4734,7 @@ public class ConcurrentHashMapV8
if (transformer == null || action == null)
throw new NullPointerException();
return new ForEachTransformedKeyTask
- (map, null, -1, null, transformer, action);
+ (map, null, -1, transformer, action);
}
/**
@@ -4437,7 +4754,7 @@ public class ConcurrentHashMapV8