--- jsr166/src/jsr166e/ConcurrentHashMapV8.java 2012/06/09 16:54:12 1.39
+++ jsr166/src/jsr166e/ConcurrentHashMapV8.java 2012/11/09 03:30:03 1.76
@@ -4,10 +4,9 @@
* http://creativecommons.org/publicdomain/zero/1.0/
*/
-// Snapshot Tue Jun 5 14:56:09 2012 Doug Lea (dl at altair)
-
package jsr166e;
-import jsr166e.LongAdder;
+
+import java.util.Comparator;
import java.util.Arrays;
import java.util.Map;
import java.util.Set;
@@ -25,6 +24,8 @@ import java.util.concurrent.ConcurrentMa
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.locks.LockSupport;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
+import java.util.concurrent.atomic.AtomicReference;
+
import java.io.Serializable;
/**
@@ -43,19 +44,22 @@ import java.io.Serializable;
* block, so may overlap with update operations (including {@code put}
* and {@code remove}). Retrievals reflect the results of the most
* recently completed update operations holding upon their
- * onset. For aggregate operations such as {@code putAll} and {@code
- * clear}, concurrent retrievals may reflect insertion or removal of
- * only some entries. Similarly, Iterators and Enumerations return
- * elements reflecting the state of the hash table at some point at or
- * since the creation of the iterator/enumeration. They do
- * not throw {@link ConcurrentModificationException}.
- * However, iterators are designed to be used by only one thread at a
- * time. Bear in mind that the results of aggregate status methods
- * including {@code size}, {@code isEmpty}, and {@code containsValue}
- * are typically useful only when a map is not undergoing concurrent
- * updates in other threads. Otherwise the results of these methods
- * reflect transient states that may be adequate for monitoring
- * or estimation purposes, but not for program control.
+ * onset. (More formally, an update operation for a given key bears a
+ * happens-before relation with any (non-null) retrieval for
+ * that key reporting the updated value.) For aggregate operations
+ * such as {@code putAll} and {@code clear}, concurrent retrievals may
+ * reflect insertion or removal of only some entries. Similarly,
+ * Iterators and Enumerations return elements reflecting the state of
+ * the hash table at some point at or since the creation of the
+ * iterator/enumeration. They do not throw {@link
+ * ConcurrentModificationException}. However, iterators are designed
+ * to be used by only one thread at a time. Bear in mind that the
+ * results of aggregate status methods including {@code size}, {@code
+ * isEmpty}, and {@code containsValue} are typically useful only when
+ * a map is not undergoing concurrent updates in other threads.
+ * Otherwise the results of these methods reflect transient states
+ * that may be adequate for monitoring or estimation purposes, but not
+ * for program control.
*
*
The table is dynamically expanded when there are too many
* collisions (i.e., keys that have distinct hash codes but fall into
@@ -78,6 +82,19 @@ import java.io.Serializable;
* {@code hashCode()} is a sure way to slow down performance of any
* hash table.
*
+ *
A {@link Set} projection of a ConcurrentHashMapV8 may be created
+ * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
+ * (using {@link #keySet(Object)} when only keys are of interest, and the
+ * mapped values are (perhaps transiently) not used or all take the
+ * same mapping value.
+ *
+ *
A ConcurrentHashMapV8 can be used as scalable frequency map (a
+ * form of histogram or multiset) by using {@link LongAdder} values
+ * and initializing via {@link #computeIfAbsent}. For example, to add
+ * a count to a {@code ConcurrentHashMapV8 freqs}, you
+ * can use {@code freqs.computeIfAbsent(k -> new
+ * LongAdder()).increment();}
+ *
* This class and its views and iterators implement all of the
* optional methods of the {@link Map} and {@link Iterator}
* interfaces.
@@ -85,52 +102,191 @@ import java.io.Serializable;
*
Like {@link Hashtable} but unlike {@link HashMap}, this class
* does not allow {@code null} to be used as a key or value.
*
+ *
ConcurrentHashMapV8s support parallel operations using the {@link
+ * ForkJoinPool#commonPool}. (Tasks that may be used in other contexts
+ * are available in class {@link ForkJoinTasks}). These operations are
+ * designed to be safely, and often sensibly, applied even with maps
+ * that are being concurrently updated by other threads; for example,
+ * when computing a snapshot summary of the values in a shared
+ * registry. There are three kinds of operation, each with four
+ * forms, accepting functions with Keys, Values, Entries, and (Key,
+ * Value) arguments and/or return values. (The first three forms are
+ * also available via the {@link #keySet()}, {@link #values()} and
+ * {@link #entrySet()} views). Because the elements of a
+ * ConcurrentHashMapV8 are not ordered in any particular way, and may be
+ * processed in different orders in different parallel executions, the
+ * correctness of supplied functions should not depend on any
+ * ordering, or on any other objects or values that may transiently
+ * change while computation is in progress; and except for forEach
+ * actions, should ideally be side-effect-free.
+ *
+ *
+ * - forEach: Perform a given action on each element.
+ * A variant form applies a given transformation on each element
+ * before performing the action.
+ *
+ * - search: Return the first available non-null result of
+ * applying a given function on each element; skipping further
+ * search when a result is found.
+ *
+ * - reduce: Accumulate each element. The supplied reduction
+ * function cannot rely on ordering (more formally, it should be
+ * both associative and commutative). There are five variants:
+ *
+ *
+ *
+ * - Plain reductions. (There is not a form of this method for
+ * (key, value) function arguments since there is no corresponding
+ * return type.)
+ *
+ * - Mapped reductions that accumulate the results of a given
+ * function applied to each element.
+ *
+ * - Reductions to scalar doubles, longs, and ints, using a
+ * given basis value.
+ *
+ *
+ *
+ *
+ *
+ * The concurrency properties of bulk operations follow
+ * from those of ConcurrentHashMapV8: Any non-null result returned
+ * from {@code get(key)} and related access methods bears a
+ * happens-before relation with the associated insertion or
+ * update. The result of any bulk operation reflects the
+ * composition of these per-element relations (but is not
+ * necessarily atomic with respect to the map as a whole unless it
+ * is somehow known to be quiescent). Conversely, because keys
+ * and values in the map are never null, null serves as a reliable
+ * atomic indicator of the current lack of any result. To
+ * maintain this property, null serves as an implicit basis for
+ * all non-scalar reduction operations. For the double, long, and
+ * int versions, the basis should be one that, when combined with
+ * any other value, returns that other value (more formally, it
+ * should be the identity element for the reduction). Most common
+ * reductions have these properties; for example, computing a sum
+ * with basis 0 or a minimum with basis MAX_VALUE.
+ *
+ *
Search and transformation functions provided as arguments
+ * should similarly return null to indicate the lack of any result
+ * (in which case it is not used). In the case of mapped
+ * reductions, this also enables transformations to serve as
+ * filters, returning null (or, in the case of primitive
+ * specializations, the identity basis) if the element should not
+ * be combined. You can create compound transformations and
+ * filterings by composing them yourself under this "null means
+ * there is nothing there now" rule before using them in search or
+ * reduce operations.
+ *
+ *
Methods accepting and/or returning Entry arguments maintain
+ * key-value associations. They may be useful for example when
+ * finding the key for the greatest value. Note that "plain" Entry
+ * arguments can be supplied using {@code new
+ * AbstractMap.SimpleEntry(k,v)}.
+ *
+ *
Bulk operations may complete abruptly, throwing an
+ * exception encountered in the application of a supplied
+ * function. Bear in mind when handling such exceptions that other
+ * concurrently executing functions could also have thrown
+ * exceptions, or would have done so if the first exception had
+ * not occurred.
+ *
+ *
Parallel speedups for bulk operations compared to sequential
+ * processing are common but not guaranteed. Operations involving
+ * brief functions on small maps may execute more slowly than
+ * sequential loops if the underlying work to parallelize the
+ * computation is more expensive than the computation itself.
+ * Similarly, parallelization may not lead to much actual parallelism
+ * if all processors are busy performing unrelated tasks.
+ *
+ *
All arguments to all task methods must be non-null.
+ *
+ *
jsr166e note: During transition, this class
+ * uses nested functional interfaces with different names but the
+ * same forms as those expected for JDK8.
+ *
* This class is a member of the
*
* Java Collections Framework.
*
- *
jsr166e note: This class is a candidate replacement for
- * java.util.concurrent.ConcurrentHashMap.
- *
* @since 1.5
* @author Doug Lea
* @param the type of keys maintained by this map
* @param the type of mapped values
*/
public class ConcurrentHashMapV8
- implements ConcurrentMap, Serializable {
+ implements ConcurrentMap, Serializable {
private static final long serialVersionUID = 7249069246763182397L;
/**
- * A function computing a mapping from the given key to a value.
- * This is a place-holder for an upcoming JDK8 interface.
+ * A partitionable iterator. A Spliterator can be traversed
+ * directly, but can also be partitioned (before traversal) by
+ * creating another Spliterator that covers a non-overlapping
+ * portion of the elements, and so may be amenable to parallel
+ * execution.
+ *
+ * This interface exports a subset of expected JDK8
+ * functionality.
+ *
+ *
Sample usage: Here is one (of the several) ways to compute
+ * the sum of the values held in a map using the ForkJoin
+ * framework. As illustrated here, Spliterators are well suited to
+ * designs in which a task repeatedly splits off half its work
+ * into forked subtasks until small enough to process directly,
+ * and then joins these subtasks. Variants of this style can also
+ * be used in completion-based designs.
+ *
+ *
+ * {@code ConcurrentHashMapV8 m = ...
+ * // split as if have 8 * parallelism, for load balance
+ * int n = m.size();
+ * int p = aForkJoinPool.getParallelism() * 8;
+ * int split = (n < p)? n : p;
+ * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
+ * // ...
+ * static class SumValues extends RecursiveTask {
+ * final Spliterator s;
+ * final int split; // split while > 1
+ * final SumValues nextJoin; // records forked subtasks to join
+ * SumValues(Spliterator s, int depth, SumValues nextJoin) {
+ * this.s = s; this.depth = depth; this.nextJoin = nextJoin;
+ * }
+ * public Long compute() {
+ * long sum = 0;
+ * SumValues subtasks = null; // fork subtasks
+ * for (int s = split >>> 1; s > 0; s >>>= 1)
+ * (subtasks = new SumValues(s.split(), s, subtasks)).fork();
+ * while (s.hasNext()) // directly process remaining elements
+ * sum += s.next();
+ * for (SumValues t = subtasks; t != null; t = t.nextJoin)
+ * sum += t.join(); // collect subtask results
+ * return sum;
+ * }
+ * }
+ * }
*/
- public static interface MappingFunction {
+ public static interface Spliterator extends Iterator {
/**
- * Returns a non-null value for the given key.
+ * Returns a Spliterator covering approximately half of the
+ * elements, guaranteed not to overlap with those subsequently
+ * returned by this Spliterator. After invoking this method,
+ * the current Spliterator will not produce any of
+ * the elements of the returned Spliterator, but the two
+ * Spliterators together will produce all of the elements that
+ * would have been produced by this Spliterator had this
+ * method not been called. The exact number of elements
+ * produced by the returned Spliterator is not guaranteed, and
+ * may be zero (i.e., with {@code hasNext()} reporting {@code
+ * false}) if this Spliterator cannot be further split.
*
- * @param key the (non-null) key
- * @return a non-null value
+ * @return a Spliterator covering approximately half of the
+ * elements
+ * @throws IllegalStateException if this Spliterator has
+ * already commenced traversing elements
*/
- V map(K key);
+ Spliterator split();
}
- /**
- * A function computing a new mapping given a key and its current
- * mapped value (or {@code null} if there is no current
- * mapping). This is a place-holder for an upcoming JDK8
- * interface.
- */
- public static interface RemappingFunction {
- /**
- * Returns a new value given a key and its current value.
- *
- * @param key the (non-null) key
- * @param value the current value, or null if there is no mapping
- * @return a non-null value
- */
- V remap(K key, V value);
- }
/*
* Overview:
@@ -283,7 +439,7 @@ public class ConcurrentHashMapV8
* 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 InternalIterator) arrange to move to the new table
+ * (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
@@ -293,12 +449,11 @@ public class ConcurrentHashMapV8
* mechanics trigger only when necessary.
*
* The traversal scheme also applies to partial traversals of
- * ranges of bins (via an alternate InternalIterator constructor)
- * to support partitioned aggregate operations (that are not
- * otherwise implemented yet). Also, read-only operations give up
- * if ever forwarded to a null table, which provides support for
- * shutdown-style clearing, which is also not currently
- * implemented.
+ * ranges of bins (via an alternate Traverser constructor)
+ * to support partitioned aggregate operations. Also, read-only
+ * operations give up if ever forwarded to a null table, which
+ * provides support for shutdown-style clearing, which is also not
+ * currently implemented.
*
* Lazy table initialization minimizes footprint until first use,
* and also avoids resizings when the first operation is from a
@@ -415,9 +570,9 @@ public class ConcurrentHashMapV8
private transient volatile int sizeCtl;
// views
- private transient KeySet keySet;
- private transient Values values;
- private transient EntrySet entrySet;
+ private transient KeySetView keySet;
+ private transient ValuesView values;
+ private transient EntrySetView entrySet;
/** For serialization compatibility. Null unless serialized; see below */
private Segment[] segments;
@@ -436,7 +591,7 @@ public class ConcurrentHashMapV8
* inline assignments below.
*/
- static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
+ static final Node tabAt(Node[] tab, int i) { // used by Iter
return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<
/**
* Key-value entry. Note that this is never exported out as a
- * user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
- * below). Nodes with a hash field of MOVED are special, and do
- * not contain user keys or values. Otherwise, keys are never
- * null, and null val fields indicate that a node is in the
- * process of being deleted or created. For purposes of read-only
- * access, a key may be read before a val, but can only be used
- * after checking val to be non-null.
+ * user-visible Map.Entry (see MapEntry below). Nodes with a hash
+ * field of MOVED are special, and do not contain user keys or
+ * values. Otherwise, keys are never null, and null val fields
+ * indicate that a node is in the process of being deleted or
+ * created. For purposes of read-only access, a key may be read
+ * before a val, but can only be used after checking val to be
+ * non-null.
*/
static class Node {
volatile int hash;
@@ -494,9 +649,13 @@ public class ConcurrentHashMapV8
* 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) { // bounds check
+ 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) {
@@ -571,15 +730,20 @@ public class ConcurrentHashMapV8
* handle this, the tree is ordered primarily by hash value, then
* by getClass().getName() order, and then by Comparator order
* among elements of the same class. On lookup at a node, if
- * non-Comparable, both left and right children may need to be
- * searched in the case of tied hash values. (This corresponds to
- * the full list search that would be necessary if all elements
- * were non-Comparable and had tied hashes.)
+ * elements are not comparable or compare as 0, both left and
+ * right children may need to be searched in the case of tied hash
+ * values. (This corresponds to the full list search that would be
+ * necessary if all elements were non-Comparable and had tied
+ * hashes.) The red-black balancing code is updated from
+ * pre-jdk-collections
+ * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
+ * based in turn on Cormen, Leiserson, and Rivest "Introduction to
+ * Algorithms" (CLR).
*
* TreeBins also maintain a separate locking discipline than
* regular bins. Because they are forwarded via special MOVED
* nodes at bin heads (which can never change once established),
- * we cannot use use those nodes as locks. Instead, TreeBin
+ * we cannot use those nodes as locks. Instead, TreeBin
* extends AbstractQueuedSynchronizer to support a simple form of
* read-write lock. For update operations and table validation,
* the exclusive form of lock behaves in the same way as bin-head
@@ -598,8 +762,8 @@ public class ConcurrentHashMapV8
*/
static final class TreeBin extends AbstractQueuedSynchronizer {
private static final long serialVersionUID = 2249069246763182397L;
- TreeNode root; // root of tree
- TreeNode first; // head of next-pointer list
+ transient TreeNode root; // root of tree
+ transient TreeNode first; // head of next-pointer list
/* AQS overrides */
public final boolean isHeldExclusively() { return getState() > 0; }
@@ -629,35 +793,70 @@ public class ConcurrentHashMapV8
return c == -1;
}
+ /** From CLR */
+ private void rotateLeft(TreeNode p) {
+ if (p != null) {
+ TreeNode r = p.right, pp, rl;
+ if ((rl = p.right = r.left) != null)
+ rl.parent = p;
+ if ((pp = r.parent = p.parent) == null)
+ root = r;
+ else if (pp.left == p)
+ pp.left = r;
+ else
+ pp.right = r;
+ r.left = p;
+ p.parent = r;
+ }
+ }
+
+ /** From CLR */
+ private void rotateRight(TreeNode p) {
+ if (p != null) {
+ TreeNode l = p.left, pp, lr;
+ if ((lr = p.left = l.right) != null)
+ lr.parent = p;
+ if ((pp = l.parent = p.parent) == null)
+ root = l;
+ else if (pp.right == p)
+ pp.right = l;
+ else
+ pp.left = l;
+ l.right = p;
+ p.parent = l;
+ }
+ }
+
/**
- * Return the TreeNode (or null if not found) for the given key
+ * Returns the TreeNode (or null if not found) for the given key
* starting at given root.
*/
- @SuppressWarnings("unchecked") // suppress Comparable cast warning
- final TreeNode getTreeNode(int h, Object k, TreeNode p) {
+ @SuppressWarnings("unchecked") final TreeNode getTreeNode
+ (int h, Object k, TreeNode p) {
Class> c = k.getClass();
while (p != null) {
- int dir, ph; Object pk; Class> pc; TreeNode r;
- if (h < (ph = p.hash))
- dir = -1;
- else if (h > ph)
- dir = 1;
- else if ((pk = p.key) == k || k.equals(pk))
- return p;
- else if (c != (pc = pk.getClass()))
- dir = c.getName().compareTo(pc.getName());
- else if (k instanceof Comparable)
- dir = ((Comparable)k).compareTo((Comparable)pk);
- else
- dir = 0;
- TreeNode pr = p.right;
- if (dir > 0)
- p = pr;
- else if (dir == 0 && pr != null && h >= pr.hash &&
- (r = getTreeNode(h, k, pr)) != null)
- return r;
+ int dir, ph; Object pk; Class> pc;
+ if ((ph = p.hash) == h) {
+ if ((pk = p.key) == k || k.equals(pk))
+ return p;
+ 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;
+ }
+ else if ((pr = p.right) != null && h >= pr.hash)
+ s = pr;
+ if (s != null && (r = getTreeNode(h, k, s)) != null)
+ return r;
+ }
+ }
else
- p = p.left;
+ dir = (h < ph) ? -1 : 1;
+ p = (dir > 0) ? p.right : p.left;
}
return null;
}
@@ -690,56 +889,104 @@ public class ConcurrentHashMapV8
}
/**
- * Find or add a node
+ * Finds or adds a node.
* @return null if added
*/
- @SuppressWarnings("unchecked") // suppress Comparable cast warning
- final TreeNode putTreeNode(int h, Object k, Object v) {
+ @SuppressWarnings("unchecked") final TreeNode putTreeNode
+ (int h, Object k, Object v) {
Class> c = k.getClass();
- TreeNode p = root;
+ TreeNode pp = root, p = null;
int dir = 0;
- if (p != null) {
- for (;;) {
- int ph; Object pk; Class> pc; TreeNode r;
- if (h < (ph = p.hash))
- dir = -1;
- else if (h > ph)
- dir = 1;
- else if ((pk = p.key) == k || k.equals(pk))
+ while (pp != null) { // find existing node or leaf to insert at
+ int ph; Object pk; Class> pc;
+ p = pp;
+ if ((ph = p.hash) == h) {
+ if ((pk = p.key) == k || k.equals(pk))
return p;
- else if (c != (pc = (pk = p.key).getClass()))
- dir = c.getName().compareTo(pc.getName());
- else if (k instanceof Comparable)
- dir = ((Comparable)k).compareTo((Comparable)pk);
- else
- dir = 0;
- TreeNode pr = p.right, pl;
- if (dir > 0) {
- if (pr == null)
- break;
- p = pr;
- }
- else if (dir == 0 && pr != null && h >= pr.hash &&
- (r = getTreeNode(h, k, pr)) != null)
- return r;
- else if ((pl = p.left) == null)
- break;
- else
- p = pl;
+ 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;
+ }
+ else if ((pr = p.right) != null && h >= pr.hash)
+ s = pr;
+ if (s != null && (r = getTreeNode(h, k, s)) != null)
+ return r;
+ }
}
+ else
+ dir = (h < ph) ? -1 : 1;
+ pp = (dir > 0) ? p.right : p.left;
}
+
TreeNode f = first;
- TreeNode r = first = new TreeNode(h, k, v, f, p);
+ TreeNode x = first = new TreeNode(h, k, v, f, p);
if (p == null)
- root = r;
- else {
+ root = x;
+ else { // attach and rebalance; adapted from CLR
+ TreeNode xp, xpp;
+ if (f != null)
+ f.prev = x;
if (dir <= 0)
- p.left = r;
+ p.left = x;
else
- p.right = r;
- if (f != null)
- f.prev = r;
- fixAfterInsertion(r);
+ p.right = x;
+ x.red = true;
+ while (x != null && (xp = x.parent) != null && xp.red &&
+ (xpp = xp.parent) != null) {
+ TreeNode xppl = xpp.left;
+ if (xp == xppl) {
+ TreeNode y = xpp.right;
+ if (y != null && y.red) {
+ y.red = false;
+ xp.red = false;
+ xpp.red = true;
+ x = xpp;
+ }
+ else {
+ if (x == xp.right) {
+ rotateLeft(x = xp);
+ xpp = (xp = x.parent) == null ? null : xp.parent;
+ }
+ if (xp != null) {
+ xp.red = false;
+ if (xpp != null) {
+ xpp.red = true;
+ rotateRight(xpp);
+ }
+ }
+ }
+ }
+ else {
+ TreeNode y = xppl;
+ if (y != null && y.red) {
+ y.red = false;
+ xp.red = false;
+ xpp.red = true;
+ x = xpp;
+ }
+ else {
+ if (x == xp.left) {
+ rotateRight(x = xp);
+ xpp = (xp = x.parent) == null ? null : xp.parent;
+ }
+ if (xp != null) {
+ xp.red = false;
+ if (xpp != null) {
+ xpp.red = true;
+ rotateLeft(xpp);
+ }
+ }
+ }
+ }
+ }
+ TreeNode r = root;
+ if (r != null && r.red)
+ r.red = false;
}
return null;
}
@@ -765,9 +1012,9 @@ public class ConcurrentHashMapV8
TreeNode pl = p.left;
TreeNode pr = p.right;
if (pl != null && pr != null) {
- TreeNode s = pr;
- while (s.left != null) // find successor
- s = s.left;
+ TreeNode s = pr, sl;
+ while ((sl = s.left) != null) // find successor
+ s = sl;
boolean c = s.red; s.red = p.red; p.red = c; // swap colors
TreeNode sr = s.right;
TreeNode pp = p.parent;
@@ -819,198 +1066,99 @@ public class ConcurrentHashMapV8
pp.right = replacement;
p.left = p.right = p.parent = null;
}
- if (!p.red)
- fixAfterDeletion(replacement);
- if (p == replacement && (pp = p.parent) != null) {
- if (p == pp.left) // detach pointers
- pp.left = null;
- else if (p == pp.right)
- pp.right = null;
- p.parent = null;
- }
- }
-
- // CLR code updated from pre-jdk-collections version at
- // http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java
-
- /** From CLR */
- private void rotateLeft(TreeNode p) {
- if (p != null) {
- TreeNode r = p.right, pp, rl;
- if ((rl = p.right = r.left) != null)
- rl.parent = p;
- if ((pp = r.parent = p.parent) == null)
- root = r;
- else if (pp.left == p)
- pp.left = r;
- else
- pp.right = r;
- r.left = p;
- p.parent = r;
- }
- }
-
- /** From CLR */
- private void rotateRight(TreeNode p) {
- if (p != null) {
- TreeNode l = p.left, pp, lr;
- if ((lr = p.left = l.right) != null)
- lr.parent = p;
- if ((pp = l.parent = p.parent) == null)
- root = l;
- else if (pp.right == p)
- pp.right = l;
- else
- pp.left = l;
- l.right = p;
- p.parent = l;
- }
- }
-
- /** From CLR */
- private void fixAfterInsertion(TreeNode x) {
- x.red = true;
- TreeNode xp, xpp;
- while (x != null && (xp = x.parent) != null && xp.red &&
- (xpp = xp.parent) != null) {
- TreeNode xppl = xpp.left;
- if (xp == xppl) {
- TreeNode y = xpp.right;
- if (y != null && y.red) {
- y.red = false;
- xp.red = false;
- xpp.red = true;
- x = xpp;
+ if (!p.red) { // rebalance, from CLR
+ TreeNode x = replacement;
+ while (x != null) {
+ TreeNode xp, xpl;
+ if (x.red || (xp = x.parent) == null) {
+ x.red = false;
+ break;
}
- else {
- if (x == xp.right) {
- x = xp;
- rotateLeft(x);
- xpp = (xp = x.parent) == null ? null : xp.parent;
- }
- if (xp != null) {
- xp.red = false;
- if (xpp != null) {
- xpp.red = true;
- rotateRight(xpp);
- }
+ if (x == (xpl = xp.left)) {
+ TreeNode sib = xp.right;
+ if (sib != null && sib.red) {
+ sib.red = false;
+ xp.red = true;
+ rotateLeft(xp);
+ sib = (xp = x.parent) == null ? null : xp.right;
}
- }
- }
- else {
- TreeNode y = xppl;
- if (y != null && y.red) {
- y.red = false;
- xp.red = false;
- xpp.red = true;
- x = xpp;
- }
- else {
- if (x == xp.left) {
+ if (sib == null)
x = xp;
- rotateRight(x);
- xpp = (xp = x.parent) == null ? null : xp.parent;
- }
- if (xp != null) {
- xp.red = false;
- if (xpp != null) {
- xpp.red = true;
- rotateLeft(xpp);
- }
- }
- }
- }
- }
- TreeNode r = root;
- if (r != null && r.red)
- r.red = false;
- }
-
- /** From CLR */
- private void fixAfterDeletion(TreeNode x) {
- while (x != null) {
- TreeNode xp, xpl;
- if (x.red || (xp = x.parent) == null) {
- x.red = false;
- break;
- }
- if (x == (xpl = xp.left)) {
- TreeNode sib = xp.right;
- if (sib != null && sib.red) {
- sib.red = false;
- xp.red = true;
- rotateLeft(xp);
- sib = (xp = x.parent) == null ? null : xp.right;
- }
- if (sib == null)
- x = xp;
- else {
- TreeNode sl = sib.left, sr = sib.right;
- if ((sr == null || !sr.red) &&
- (sl == null || !sl.red)) {
- sib.red = true;
- x = xp;
- }
else {
- if (sr == null || !sr.red) {
- if (sl != null)
- sl.red = false;
+ TreeNode sl = sib.left, sr = sib.right;
+ if ((sr == null || !sr.red) &&
+ (sl == null || !sl.red)) {
sib.red = true;
- rotateRight(sib);
- sib = (xp = x.parent) == null ? null : xp.right;
+ x = xp;
}
- if (sib != null) {
- sib.red = (xp == null) ? false : xp.red;
- if ((sr = sib.right) != null)
- sr.red = false;
- }
- if (xp != null) {
- xp.red = false;
- rotateLeft(xp);
+ else {
+ if (sr == null || !sr.red) {
+ if (sl != null)
+ sl.red = false;
+ sib.red = true;
+ rotateRight(sib);
+ sib = (xp = x.parent) == null ? null : xp.right;
+ }
+ if (sib != null) {
+ sib.red = (xp == null) ? false : xp.red;
+ if ((sr = sib.right) != null)
+ sr.red = false;
+ }
+ if (xp != null) {
+ xp.red = false;
+ rotateLeft(xp);
+ }
+ x = root;
}
- x = root;
}
}
- }
- else { // symmetric
- TreeNode sib = xpl;
- if (sib != null && sib.red) {
- sib.red = false;
- xp.red = true;
- rotateRight(xp);
- sib = (xp = x.parent) == null ? null : xp.left;
- }
- if (sib == null)
- x = xp;
- else {
- TreeNode sl = sib.left, sr = sib.right;
- if ((sl == null || !sl.red) &&
- (sr == null || !sr.red)) {
- sib.red = true;
- x = xp;
+ else { // symmetric
+ TreeNode sib = xpl;
+ if (sib != null && sib.red) {
+ sib.red = false;
+ xp.red = true;
+ rotateRight(xp);
+ sib = (xp = x.parent) == null ? null : xp.left;
}
+ if (sib == null)
+ x = xp;
else {
- if (sl == null || !sl.red) {
- if (sr != null)
- sr.red = false;
+ TreeNode sl = sib.left, sr = sib.right;
+ if ((sl == null || !sl.red) &&
+ (sr == null || !sr.red)) {
sib.red = true;
- rotateLeft(sib);
- sib = (xp = x.parent) == null ? null : xp.left;
- }
- if (sib != null) {
- sib.red = (xp == null) ? false : xp.red;
- if ((sl = sib.left) != null)
- sl.red = false;
+ x = xp;
}
- if (xp != null) {
- xp.red = false;
- rotateRight(xp);
+ else {
+ if (sl == null || !sl.red) {
+ if (sr != null)
+ sr.red = false;
+ sib.red = true;
+ rotateLeft(sib);
+ sib = (xp = x.parent) == null ? null : xp.left;
+ }
+ if (sib != null) {
+ sib.red = (xp == null) ? false : xp.red;
+ if ((sl = sib.left) != null)
+ sl.red = false;
+ }
+ if (xp != null) {
+ xp.red = false;
+ rotateRight(xp);
+ }
+ x = root;
}
- x = root;
}
}
}
}
+ if (p == replacement && (pp = p.parent) != null) {
+ if (p == pp.left) // detach pointers
+ pp.left = null;
+ else if (p == pp.right)
+ pp.right = null;
+ p.parent = null;
+ }
}
}
@@ -1025,7 +1173,7 @@ public class ConcurrentHashMapV8
* we apply a transform that spreads the impact of higher bits
* downward. There is a tradeoff between speed, utility, and
* quality of bit-spreading. Because many common sets of hashes
- * are already reaonably distributed across bits (so don't benefit
+ * are already reasonably distributed across bits (so don't benefit
* from spreading), and because we use trees to handle large sets
* of collisions in bins, we don't need excessively high quality.
*/
@@ -1172,7 +1320,7 @@ public class ConcurrentHashMapV8
}
/*
- * Internal versions of the five insertion methods, each a
+ * 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):
* 1. If table uninitialized, create
@@ -1190,6 +1338,8 @@ public class ConcurrentHashMapV8
* 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.
*
@@ -1386,7 +1536,7 @@ public class ConcurrentHashMapV8
/** Implementation for computeIfAbsent */
private final Object internalComputeIfAbsent(K k,
- MappingFunction super K, ?> mf) {
+ Fun super K, ?> mf) {
int h = spread(k.hashCode());
Object val = null;
int count = 0;
@@ -1399,7 +1549,7 @@ public class ConcurrentHashMapV8
if (casTabAt(tab, i, null, node)) {
count = 1;
try {
- if ((val = mf.map(k)) != null)
+ if ((val = mf.apply(k)) != null)
node.val = val;
} finally {
if (val == null)
@@ -1424,7 +1574,7 @@ public class ConcurrentHashMapV8
TreeNode p = t.getTreeNode(h, k, t.root);
if (p != null)
val = p.val;
- else if ((val = mf.map(k)) != null) {
+ else if ((val = mf.apply(k)) != null) {
added = true;
count = 2;
t.putTreeNode(h, k, val);
@@ -1478,7 +1628,7 @@ public class ConcurrentHashMapV8
}
Node last = e;
if ((e = e.next) == null) {
- if ((val = mf.map(k)) != null) {
+ if ((val = mf.apply(k)) != null) {
added = true;
last.next = new Node(h, k, val, null);
if (count >= TREE_THRESHOLD)
@@ -1504,37 +1654,38 @@ public class ConcurrentHashMapV8
}
}
}
- if (val == null)
- throw new NullPointerException();
- counter.add(1L);
- if (count > 1)
- checkForResize();
+ if (val != null) {
+ counter.add(1L);
+ if (count > 1)
+ checkForResize();
+ }
return val;
}
/** Implementation for compute */
- @SuppressWarnings("unchecked")
- private final Object internalCompute(K k,
- RemappingFunction super K, V> mf) {
+ @SuppressWarnings("unchecked") private final Object internalCompute
+ (K k, boolean onlyIfPresent, BiFun super K, ? super V, ? extends V> mf) {
int h = spread(k.hashCode());
Object val = null;
- boolean added = false;
+ int delta = 0;
int count = 0;
for (Node[] tab = table;;) {
Node f; int i, fh; Object fk;
if (tab == null)
tab = initTable();
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.remap(k, null)) != null) {
+ if ((val = mf.apply(k, null)) != null) {
node.val = val;
- added = true;
+ delta = 1;
}
} finally {
- if (!added)
+ if (delta == 0)
setTabAt(tab, i, null);
if (!node.casHash(fh, h)) {
node.hash = h;
@@ -1554,15 +1705,19 @@ public class ConcurrentHashMapV8
count = 1;
TreeNode p = t.getTreeNode(h, k, t.root);
Object pv = (p == null) ? null : p.val;
- if ((val = mf.remap(k, (V)pv)) != null) {
+ if ((val = mf.apply(k, (V)pv)) != null) {
if (p != null)
p.val = val;
else {
count = 2;
- added = true;
+ delta = 1;
t.putTreeNode(h, k, val);
}
}
+ else if (p != null) {
+ delta = -1;
+ t.deleteTreeNode(p);
+ }
}
} finally {
t.release(0);
@@ -1581,21 +1736,29 @@ public class ConcurrentHashMapV8
try {
if (tabAt(tab, i) == f) {
count = 1;
- for (Node e = f;; ++count) {
+ for (Node e = f, pred = null;; ++count) {
Object ek, ev;
if ((e.hash & HASH_BITS) == h &&
(ev = e.val) != null &&
((ek = e.key) == k || k.equals(ek))) {
- val = mf.remap(k, (V)ev);
+ val = mf.apply(k, (V)ev);
if (val != null)
e.val = val;
+ else {
+ delta = -1;
+ Node en = e.next;
+ if (pred != null)
+ pred.next = en;
+ else
+ setTabAt(tab, i, en);
+ }
break;
}
- Node last = e;
+ pred = e;
if ((e = e.next) == null) {
- if ((val = mf.remap(k, null)) != null) {
- last.next = new Node(h, k, val, null);
- added = true;
+ if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
+ pred.next = new Node(h, k, val, null);
+ delta = 1;
if (count >= TREE_THRESHOLD)
replaceWithTreeBin(tab, i, k);
}
@@ -1616,10 +1779,116 @@ public class ConcurrentHashMapV8
}
}
}
- if (val == null)
- throw new NullPointerException();
- if (added) {
- counter.add(1L);
+ if (delta != 0) {
+ counter.add((long)delta);
+ if (count > 1)
+ checkForResize();
+ }
+ return val;
+ }
+
+ /** Implementation for merge */
+ @SuppressWarnings("unchecked") private final Object internalMerge
+ (K k, V v, BiFun super V, ? super V, ? extends V> mf) {
+ int h = spread(k.hashCode());
+ Object val = null;
+ int delta = 0;
+ 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))) {
+ delta = 1;
+ val = v;
+ break;
+ }
+ }
+ 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) {
+ count = 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;
+ delta = 1;
+ t.putTreeNode(h, k, val);
+ }
+ }
+ else if (p != null) {
+ delta = -1;
+ t.deleteTreeNode(p);
+ }
+ }
+ } finally {
+ t.release(0);
+ }
+ if (count != 0)
+ break;
+ }
+ else
+ tab = (Node[])fk;
+ }
+ else if ((fh & LOCKED) != 0) {
+ checkForResize();
+ f.tryAwaitLock(tab, i);
+ }
+ else if (f.casHash(fh, fh | LOCKED)) {
+ try {
+ if (tabAt(tab, i) == f) {
+ count = 1;
+ for (Node e = f, pred = null;; ++count) {
+ Object ek, ev;
+ if ((e.hash & HASH_BITS) == h &&
+ (ev = e.val) != null &&
+ ((ek = e.key) == k || k.equals(ek))) {
+ val = mf.apply(v, (V)ev);
+ if (val != null)
+ e.val = val;
+ else {
+ delta = -1;
+ Node en = e.next;
+ if (pred != null)
+ pred.next = en;
+ else
+ setTabAt(tab, i, en);
+ }
+ break;
+ }
+ pred = e;
+ if ((e = e.next) == null) {
+ val = v;
+ pred.next = new Node(h, k, val, null);
+ delta = 1;
+ 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 (tab.length <= 64)
+ count = 2;
+ break;
+ }
+ }
+ }
+ if (delta != 0) {
+ counter.add((long)delta);
if (count > 1)
checkForResize();
}
@@ -1850,7 +2119,7 @@ public class ConcurrentHashMapV8
for (int i = bin;;) { // start upwards sweep
int fh; Node f;
if ((f = tabAt(tab, i)) == null) {
- if (bin >= 0) { // no lock needed (or available)
+ if (bin >= 0) { // Unbuffered; no lock needed (or available)
if (!casTabAt(tab, i, f, fwd))
continue;
}
@@ -1937,8 +2206,8 @@ public class ConcurrentHashMapV8
}
/**
- * Split a normal bin with list headed by e into lo and hi parts;
- * install in given table
+ * 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
@@ -1968,7 +2237,7 @@ public class ConcurrentHashMapV8
}
/**
- * Split a tree bin into lo and hi parts; install in given table
+ * 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;
@@ -2026,8 +2295,10 @@ public class ConcurrentHashMapV8
try {
if (tabAt(tab, i) == f) {
for (Node p = t.first; p != null; p = p.next) {
- p.val = null;
- --delta;
+ if (p.val != null) { // (currently always true)
+ p.val = null;
+ --delta;
+ }
}
t.first = null;
t.root = null;
@@ -2049,8 +2320,10 @@ public class ConcurrentHashMapV8
try {
if (tabAt(tab, i) == f) {
for (Node e = f; e != null; e = e.next) {
- e.val = null;
- --delta;
+ if (e.val != null) { // (currently always true)
+ e.val = null;
+ --delta;
+ }
}
setTabAt(tab, i, null);
++i;
@@ -2071,7 +2344,7 @@ public class ConcurrentHashMapV8
/**
* Encapsulates traversal for methods such as containsValue; also
- * serves as a base class for other iterators.
+ * serves as a base class for other iterators and bulk tasks.
*
* At each step, the iterator snapshots the key ("nextKey") and
* value ("nextVal") of a valid node (i.e., one that, at point of
@@ -2079,14 +2352,16 @@ public class ConcurrentHashMapV8
* change (including to null, indicating deletion), field nextVal
* might not be accurate at point of use, but still maintains the
* weak consistency property of holding a value that was once
- * valid.
+ * valid. To support iterator.remove, the nextKey field is not
+ * updated (nulled out) when the iterator cannot advance.
*
* Internal traversals directly access these fields, as in:
- * {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
+ * {@code while (it.advance() != null) { process(it.nextKey); }}
*
- * Exported iterators (subclasses of ViewIterator) extract key,
- * value, or key-value pairs as return values of Iterator.next(),
- * and encapsulate the it.next check as hasNext();
+ * Exported iterators must track whether the iterator has advanced
+ * (in hasNext vs next) (by setting/checking/nulling field
+ * nextVal), and then extract key, value, or key-value pairs as
+ * return values of next().
*
* The iterator visits once each still-valid node that was
* reachable upon iterator construction. It might miss some that
@@ -2105,51 +2380,66 @@ public class ConcurrentHashMapV8
* across threads, iteration terminates if a bounds checks fails
* for a table read.
*
- * The range-based constructor enables creation of parallel
- * range-splitting traversals. (Not yet implemented.)
+ * 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.
*/
- static class InternalIterator {
+ @SuppressWarnings("serial") static class Traverser extends ForkJoinTask {
+ final ConcurrentHashMapV8 map;
Node next; // the next entry to use
- Node last; // the last entry used
Object nextKey; // cached key field of next
Object nextVal; // cached val field of next
Node[] tab; // current table; updated if resized
int index; // index of bin to use next
int baseIndex; // current index of initial table
- final int baseLimit; // index bound for initial table
- final int baseSize; // initial table size
+ int baseLimit; // index bound for initial table
+ int baseSize; // initial table size
/** Creates iterator for all entries in the table. */
- InternalIterator(Node[] tab) {
- this.tab = tab;
- baseLimit = baseSize = (tab == null) ? 0 : tab.length;
- index = baseIndex = 0;
- next = null;
- advance();
- }
-
- /** Creates iterator for the given range of the table */
- InternalIterator(Node[] tab, int lo, int hi) {
- this.tab = tab;
- baseSize = (tab == null) ? 0 : tab.length;
- baseLimit = (hi <= baseSize) ? hi : baseSize;
- index = baseIndex = (lo >= 0) ? lo : 0;
- next = null;
- advance();
- }
-
- /** Advances next. See above for explanation. */
- final void advance() {
- Node e = last = next;
+ 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;
+ }
+
+ /**
+ * Advances next; returns nextVal or null if terminated.
+ * See above for explanation.
+ */
+ final Object advance() {
+ Node e = next;
+ Object ev = null;
outer: do {
if (e != null) // advance past used/skipped node
e = e.next;
while (e == null) { // get to next non-null bin
+ ConcurrentHashMapV8 m;
Node[] t; int b, i, n; Object ek; // checks must use locals
- if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
- (t = tab) == null || i >= (n = t.length))
+ if ((t = tab) != null)
+ n = t.length;
+ else if ((m = map) != null && (t = tab = m.table) != null)
+ n = baseLimit = baseSize = t.length;
+ else
+ break outer;
+ if ((b = baseIndex) >= baseLimit ||
+ (i = index) < 0 || i >= n)
break outer;
- else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
+ if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
if ((ek = e.key) instanceof TreeBin)
e = ((TreeBin)ek).first;
else {
@@ -2160,15 +2450,32 @@ public class ConcurrentHashMapV8
index = (i += baseSize) < n ? i : (baseIndex = b + 1);
}
nextKey = e.key;
- } while ((nextVal = e.val) == null);// skip deleted or special nodes
+ } while ((ev = e.val) == null); // skip deleted or special nodes
next = e;
+ return nextVal = ev;
}
+
+ public final void remove() {
+ Object k = nextKey;
+ if (k == null && (advance() == null || (k = nextKey) == null))
+ throw new IllegalStateException();
+ map.internalReplace(k, null, null);
+ }
+
+ public final boolean hasNext() {
+ return nextVal != null || advance() != null;
+ }
+
+ public final boolean hasMoreElements() { return hasNext(); }
+ public final void setRawResult(Object x) { }
+ public R getRawResult() { return null; }
+ public boolean exec() { return true; }
}
/* ---------------- Public operations -------------- */
/**
- * Creates a new, empty map with the default initial table size (16),
+ * Creates a new, empty map with the default initial table size (16).
*/
public ConcurrentHashMapV8() {
this.counter = new LongAdder();
@@ -2249,13 +2556,39 @@ public class ConcurrentHashMapV8
if (initialCapacity < concurrencyLevel) // Use at least as many bins
initialCapacity = concurrencyLevel; // as estimated threads
long size = (long)(1.0 + (long)initialCapacity / loadFactor);
- int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
- MAXIMUM_CAPACITY: tableSizeFor((int)size));
+ int cap = (size >= (long)MAXIMUM_CAPACITY) ?
+ MAXIMUM_CAPACITY : tableSizeFor((int)size);
this.counter = new LongAdder();
this.sizeCtl = cap;
}
/**
+ * Creates a new {@link Set} backed by a ConcurrentHashMapV8
+ * from the given type to {@code Boolean.TRUE}.
+ *
+ * @return the new set
+ */
+ public static KeySetView newKeySet() {
+ return new KeySetView(new ConcurrentHashMapV8(),
+ Boolean.TRUE);
+ }
+
+ /**
+ * Creates a new {@link Set} backed by a ConcurrentHashMapV8
+ * from the given type to {@code Boolean.TRUE}.
+ *
+ * @param initialCapacity The implementation performs internal
+ * sizing to accommodate this many elements.
+ * @throws IllegalArgumentException if the initial capacity of
+ * elements is negative
+ * @return the new set
+ */
+ public static KeySetView newKeySet(int initialCapacity) {
+ return new KeySetView(new ConcurrentHashMapV8(initialCapacity),
+ Boolean.TRUE);
+ }
+
+ /**
* {@inheritDoc}
*/
public boolean isEmpty() {
@@ -2272,9 +2605,18 @@ public class ConcurrentHashMapV8
(int)n);
}
- final long longSize() { // accurate version of size needed for views
+ /**
+ * 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.
+ *
+ * @return the number of mappings
+ */
+ public long mappingCount() {
long n = counter.sum();
- return (n < 0L) ? 0L : n;
+ return (n < 0L) ? 0L : n; // ignore transient negative values
}
/**
@@ -2288,14 +2630,30 @@ public class ConcurrentHashMapV8
*
* @throws NullPointerException if the specified key is null
*/
- @SuppressWarnings("unchecked")
- public V get(Object key) {
+ @SuppressWarnings("unchecked") public V get(Object key) {
if (key == null)
throw new NullPointerException();
return (V)internalGet(key);
}
/**
+ * Returns the value to which the specified key is mapped,
+ * or the given defaultValue if this map contains no mapping for the key.
+ *
+ * @param key the key
+ * @param defaultValue the value to return if this map contains
+ * no mapping for the given key
+ * @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;
+ }
+
+ /**
* Tests if the specified object is a key in this table.
*
* @param key possible key
@@ -2324,11 +2682,10 @@ public class ConcurrentHashMapV8
if (value == null)
throw new NullPointerException();
Object v;
- InternalIterator it = new InternalIterator(table);
- while (it.next != null) {
- if ((v = it.nextVal) == value || value.equals(v))
+ Traverser it = new Traverser(this);
+ while ((v = it.advance()) != null) {
+ if (v == value || value.equals(v))
return true;
- it.advance();
}
return false;
}
@@ -2365,8 +2722,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V put(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalPut(key, value);
@@ -2379,8 +2735,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalPutIfAbsent(key, value);
@@ -2399,93 +2754,168 @@ public class ConcurrentHashMapV8
/**
* If the specified key is not already associated with a value,
- * computes its value using the given mappingFunction and
- * enters it into the map. This is equivalent to
+ * computes its value using the given mappingFunction and enters
+ * it into the map unless null. This is equivalent to
* {@code
* if (map.containsKey(key))
* return map.get(key);
- * value = mappingFunction.map(key);
- * map.put(key, value);
+ * value = mappingFunction.apply(key);
+ * if (value != null)
+ * map.put(key, value);
* return value;}
*
* except that the action is performed atomically. If the
- * function returns {@code null} (in which case a {@code
- * NullPointerException} is thrown), or the function itself throws
- * an (unchecked) exception, the exception is rethrown to its
- * caller, and no mapping is recorded. Some attempted update
- * operations on this map by other threads may be blocked while
- * computation is in progress, so the computation should be short
- * and simple, and must not attempt to update any other mappings
- * of this Map. The most appropriate usage is to construct a new
- * object serving as an initial mapped value, or memoized result,
- * as in:
+ * function returns {@code null} no mapping is recorded. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and no mapping is recorded. Some
+ * attempted update operations on this map by other threads may be
+ * blocked while computation is in progress, so the computation
+ * should be short and simple, and must not attempt to update any
+ * other mappings of this Map. The most appropriate usage is to
+ * construct a new object serving as an initial mapped value, or
+ * memoized result, as in:
*
* {@code
- * map.computeIfAbsent(key, new MappingFunction() {
+ * map.computeIfAbsent(key, new Fun() {
* public V map(K k) { return new Value(f(k)); }});}
*
* @param key key with which the specified value is to be associated
* @param mappingFunction the function to compute a value
* @return the current (existing or computed) value associated with
- * the specified key.
- * @throws NullPointerException if the specified key, mappingFunction,
- * or computed value is null
+ * the specified key, or null if the computed value is null
+ * @throws NullPointerException if the specified key or mappingFunction
+ * is null
* @throws IllegalStateException if the computation detectably
* attempts a recursive update to this map that would
* otherwise never complete
* @throws RuntimeException or Error if the mappingFunction does so,
* in which case the mapping is left unestablished
*/
- @SuppressWarnings("unchecked")
- public V computeIfAbsent(K key, MappingFunction super K, ? extends V> mappingFunction) {
+ @SuppressWarnings("unchecked") public V computeIfAbsent
+ (K key, Fun super K, ? extends V> mappingFunction) {
if (key == null || mappingFunction == null)
throw new NullPointerException();
return (V)internalComputeIfAbsent(key, mappingFunction);
}
/**
- * Computes and enters a new mapping value given a key and
+ * If the given key is present, computes a new mapping value given a key and
+ * its current mapped value. This is equivalent to
+ * {@code
+ * if (map.containsKey(key)) {
+ * value = remappingFunction.apply(key, map.get(key));
+ * if (value != null)
+ * map.put(key, value);
+ * else
+ * map.remove(key);
+ * }
+ * }
+ *
+ * except that the action is performed atomically. If the
+ * function returns {@code null}, the mapping is removed. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and the current mapping is left
+ * unchanged. Some attempted update operations on this map by
+ * other threads may be blocked while computation is in progress,
+ * so the computation should be short and simple, and must not
+ * attempt to update any other mappings of this Map. For example,
+ * to either create or append new messages to a value mapping:
+ *
+ * @param key key with which the specified value is to be associated
+ * @param remappingFunction the function to compute a value
+ * @return the new value associated with the specified key, or null if none
+ * @throws NullPointerException if the specified key or remappingFunction
+ * is null
+ * @throws IllegalStateException if the computation detectably
+ * attempts a recursive update to this map that would
+ * otherwise never complete
+ * @throws RuntimeException or Error if the remappingFunction does so,
+ * in which case the mapping is unchanged
+ */
+ @SuppressWarnings("unchecked") public V computeIfPresent
+ (K key, BiFun super K, ? super V, ? extends V> remappingFunction) {
+ if (key == null || remappingFunction == null)
+ throw new NullPointerException();
+ return (V)internalCompute(key, true, remappingFunction);
+ }
+
+ /**
+ * Computes a new mapping value given a key and
* its current mapped value (or {@code null} if there is no current
* mapping). This is equivalent to
* {@code
- * map.put(key, remappingFunction.remap(key, map.get(key));
+ * value = remappingFunction.apply(key, map.get(key));
+ * if (value != null)
+ * map.put(key, value);
+ * else
+ * map.remove(key);
* }
*
* except that the action is performed atomically. If the
- * function returns {@code null} (in which case a {@code
- * NullPointerException} is thrown), or the function itself throws
- * an (unchecked) exception, the exception is rethrown to its
- * caller, and current mapping is left unchanged. Some attempted
- * update operations on this map by other threads may be blocked
- * while computation is in progress, so the computation should be
- * short and simple, and must not attempt to update any other
- * mappings of this Map. For example, to either create or
- * append new messages to a value mapping:
+ * function returns {@code null}, the mapping is removed. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and the current mapping is left
+ * unchanged. Some attempted update operations on this map by
+ * other threads may be blocked while computation is in progress,
+ * so the computation should be short and simple, and must not
+ * attempt to update any other mappings of this Map. For example,
+ * to either create or append new messages to a value mapping:
*
* {@code
* Map map = ...;
* final String msg = ...;
- * map.compute(key, new RemappingFunction() {
- * public String remap(Key k, String v) {
+ * map.compute(key, new BiFun() {
+ * public String apply(Key k, String v) {
* return (v == null) ? msg : v + msg;});}}
*
* @param key key with which the specified value is to be associated
* @param remappingFunction the function to compute a value
- * @return the new value associated with
- * the specified key.
+ * @return the new value associated with the specified key, or null if none
* @throws NullPointerException if the specified key or remappingFunction
- * or computed value is null
+ * is null
* @throws IllegalStateException if the computation detectably
* attempts a recursive update to this map that would
* otherwise never complete
* @throws RuntimeException or Error if the remappingFunction does so,
* in which case the mapping is unchanged
*/
- @SuppressWarnings("unchecked")
- public V compute(K key, RemappingFunction super K, V> remappingFunction) {
+ @SuppressWarnings("unchecked") public V compute
+ (K key, BiFun super K, ? super V, ? extends V> remappingFunction) {
if (key == null || remappingFunction == null)
throw new NullPointerException();
- return (V)internalCompute(key, remappingFunction);
+ return (V)internalCompute(key, false, remappingFunction);
+ }
+
+ /**
+ * If the specified key is not already associated
+ * with a value, associate it with the given value.
+ * Otherwise, replace the value with the results of
+ * the given remapping function. This is equivalent to:
+ * {@code
+ * if (!map.containsKey(key))
+ * map.put(value);
+ * else {
+ * newValue = remappingFunction.apply(map.get(key), value);
+ * if (value != null)
+ * map.put(key, value);
+ * else
+ * map.remove(key);
+ * }
+ * }
+ * except that the action is performed atomically. If the
+ * function returns {@code null}, the mapping is removed. If the
+ * function itself throws an (unchecked) exception, the exception
+ * is rethrown to its caller, and the current mapping is left
+ * unchanged. Some attempted update operations on this map by
+ * other threads may be blocked while computation is in progress,
+ * 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 super V, ? super V, ? extends V> remappingFunction) {
+ if (key == null || value == null || remappingFunction == null)
+ throw new NullPointerException();
+ return (V)internalMerge(key, value, remappingFunction);
}
/**
@@ -2497,8 +2927,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V remove(Object key) {
if (key == null)
throw new NullPointerException();
return (V)internalReplace(key, null, null);
@@ -2535,8 +2964,7 @@ 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) {
+ @SuppressWarnings("unchecked") public V replace(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return (V)internalReplace(key, value, null);
@@ -2552,43 +2980,41 @@ public class ConcurrentHashMapV8
/**
* Returns a {@link Set} view of the keys contained in this map.
* The set is backed by the map, so changes to the map are
- * reflected in the set, and vice-versa. The set supports element
- * removal, which removes the corresponding mapping from this map,
- * via the {@code Iterator.remove}, {@code Set.remove},
- * {@code removeAll}, {@code retainAll}, and {@code clear}
- * operations. It does not support the {@code add} or
- * {@code addAll} operations.
+ * reflected in the set, and vice-versa.
*
- * 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.
+ * @return the set view
*/
- public Set keySet() {
- KeySet ks = keySet;
- return (ks != null) ? ks : (keySet = new KeySet(this));
+ public KeySetView keySet() {
+ KeySetView ks = keySet;
+ return (ks != null) ? ks : (keySet = new KeySetView(this, null));
+ }
+
+ /**
+ * Returns a {@link Set} view of the keys in this map, using the
+ * given common mapped value for any additions (i.e., {@link
+ * Collection#add} and {@link Collection#addAll}). This is of
+ * course only appropriate if it is acceptable to use the same
+ * value for all additions from this view.
+ *
+ * @param mappedValue the mapped value to use for any
+ * additions.
+ * @return the set view
+ * @throws NullPointerException if the mappedValue is null
+ */
+ public KeySetView keySet(V mappedValue) {
+ if (mappedValue == null)
+ throw new NullPointerException();
+ return new KeySetView(this, mappedValue);
}
/**
* 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));
}
/**
@@ -2608,8 +3034,8 @@ 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));
}
/**
@@ -2633,6 +3059,33 @@ public class ConcurrentHashMapV8
}
/**
+ * Returns a partitionable iterator of the keys in this map.
+ *
+ * @return a partitionable iterator of the keys in this map
+ */
+ public Spliterator keySpliterator() {
+ return new KeyIterator(this);
+ }
+
+ /**
+ * Returns a partitionable iterator of the values in this map.
+ *
+ * @return a partitionable iterator of the values in this map
+ */
+ public Spliterator valueSpliterator() {
+ return new ValueIterator(this);
+ }
+
+ /**
+ * Returns a partitionable iterator of the entries in this map.
+ *
+ * @return a partitionable iterator of the entries in this map
+ */
+ public Spliterator> entrySpliterator() {
+ return new EntryIterator(this);
+ }
+
+ /**
* Returns the hash code value for this {@link Map}, i.e.,
* the sum of, for each key-value pair in the map,
* {@code key.hashCode() ^ value.hashCode()}.
@@ -2641,10 +3094,10 @@ public class ConcurrentHashMapV8
*/
public int hashCode() {
int h = 0;
- InternalIterator it = new InternalIterator(table);
- while (it.next != null) {
- h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
- it.advance();
+ Traverser it = new Traverser(this);
+ Object v;
+ while ((v = it.advance()) != null) {
+ h += it.nextKey.hashCode() ^ v.hashCode();
}
return h;
}
@@ -2661,17 +3114,17 @@ public class ConcurrentHashMapV8
* @return a string representation of this map
*/
public String toString() {
- InternalIterator it = new InternalIterator(table);
+ Traverser it = new Traverser(this);
StringBuilder sb = new StringBuilder();
sb.append('{');
- if (it.next != null) {
+ Object v;
+ if ((v = it.advance()) != null) {
for (;;) {
- Object k = it.nextKey, v = it.nextVal;
+ Object k = it.nextKey;
sb.append(k == this ? "(this Map)" : k);
sb.append('=');
sb.append(v == this ? "(this Map)" : v);
- it.advance();
- if (it.next == null)
+ if ((v = it.advance()) == null)
break;
sb.append(',').append(' ');
}
@@ -2694,13 +3147,12 @@ public class ConcurrentHashMapV8
if (!(o instanceof Map))
return false;
Map,?> m = (Map,?>) o;
- InternalIterator it = new InternalIterator(table);
- while (it.next != null) {
- Object val = it.nextVal;
+ Traverser it = new Traverser(this);
+ Object val;
+ while ((val = it.advance()) != null) {
Object v = m.get(it.nextKey);
if (v == null || (v != val && !v.equals(val)))
return false;
- it.advance();
}
for (Map.Entry,?> e : m.entrySet()) {
Object mk, mv, v;
@@ -2716,97 +3168,85 @@ public class ConcurrentHashMapV8
/* ----------------Iterators -------------- */
- /**
- * Base class for key, value, and entry iterators. Adds a map
- * reference to InternalIterator to support Iterator.remove.
- */
- static abstract class ViewIterator extends InternalIterator {
- final ConcurrentHashMapV8 map;
- ViewIterator(ConcurrentHashMapV8 map) {
- super(map.table);
- this.map = map;
+ @SuppressWarnings("serial") static final class KeyIterator extends Traverser
+ implements Spliterator, Enumeration {
+ KeyIterator(ConcurrentHashMapV8 map) { super(map); }
+ KeyIterator(Traverser it) {
+ super(it);
}
-
- public final void remove() {
- if (last == null)
+ public KeyIterator split() {
+ if (nextKey != null)
throw new IllegalStateException();
- map.remove(last.key);
- last = null;
+ return new KeyIterator(this);
}
-
- public final boolean hasNext() { return next != null; }
- public final boolean hasMoreElements() { return next != null; }
- }
-
- static final class KeyIterator extends ViewIterator
- implements Iterator, Enumeration {
- KeyIterator(ConcurrentHashMapV8 map) { super(map); }
-
- @SuppressWarnings("unchecked")
- public final K next() {
- if (next == null)
+ @SuppressWarnings("unchecked") public final K next() {
+ if (nextVal == null && advance() == null)
throw new NoSuchElementException();
Object k = nextKey;
- advance();
- return (K)k;
+ nextVal = null;
+ return (K) k;
}
public final K nextElement() { return next(); }
}
- static final class ValueIterator extends ViewIterator
- implements Iterator, Enumeration {
+ @SuppressWarnings("serial") static final class ValueIterator extends Traverser
+ implements Spliterator, Enumeration {
ValueIterator(ConcurrentHashMapV8 map) { super(map); }
+ ValueIterator(Traverser it) {
+ super(it);
+ }
+ public ValueIterator split() {
+ if (nextKey != null)
+ throw new IllegalStateException();
+ return new ValueIterator(this);
+ }
- @SuppressWarnings("unchecked")
- public final V next() {
- if (next == null)
+ @SuppressWarnings("unchecked") public final V next() {
+ Object v;
+ if ((v = nextVal) == null && (v = advance()) == null)
throw new NoSuchElementException();
- Object v = nextVal;
- advance();
- return (V)v;
+ nextVal = null;
+ return (V) v;
}
public final V nextElement() { return next(); }
}
- static final class EntryIterator extends ViewIterator
- implements Iterator> {
+ @SuppressWarnings("serial") static final class EntryIterator extends Traverser
+ implements Spliterator> {
EntryIterator(ConcurrentHashMapV8 map) { super(map); }
-
- @SuppressWarnings("unchecked")
- public final Map.Entry next() {
- if (next == null)
- throw new NoSuchElementException();
- Object k = nextKey;
- Object v = nextVal;
- advance();
- return new WriteThroughEntry((K)k, (V)v, map);
+ EntryIterator(Traverser it) {
+ super(it);
+ }
+ public EntryIterator split() {
+ if (nextKey != null)
+ throw new IllegalStateException();
+ return new EntryIterator(this);
}
- }
-
- static final class SnapshotEntryIterator extends ViewIterator
- implements Iterator> {
- SnapshotEntryIterator(ConcurrentHashMapV8 map) { super(map); }
- @SuppressWarnings("unchecked")
- public final Map.Entry next() {
- if (next == null)
+ @SuppressWarnings("unchecked") public final Map.Entry next() {
+ Object v;
+ if ((v = nextVal) == null && (v = advance()) == null)
throw new NoSuchElementException();
Object k = nextKey;
- Object v = nextVal;
- advance();
- return new SnapshotEntry((K)k, (V)v);
+ nextVal = null;
+ return new MapEntry((K)k, (V)v, map);
}
}
/**
- * Base of writeThrough and Snapshot entry classes
+ * Exported Entry for iterators
*/
- static abstract class MapEntry implements Map.Entry {
+ static final class MapEntry implements Map.Entry {
final K key; // non-null
V val; // non-null
- MapEntry(K key, V val) { this.key = key; this.val = val; }
+ final ConcurrentHashMapV8 map;
+ MapEntry(K key, V val, ConcurrentHashMapV8 map) {
+ this.key = key;
+ this.val = val;
+ this.map = map;
+ }
public final K getKey() { return key; }
public final V getValue() { return val; }
public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
@@ -2821,29 +3261,13 @@ public class ConcurrentHashMapV8
(v == val || v.equals(val)));
}
- public abstract V setValue(V value);
- }
-
- /**
- * Entry used by EntryIterator.next(), that relays setValue
- * changes to the underlying map.
- */
- static final class WriteThroughEntry extends MapEntry
- implements Map.Entry {
- final ConcurrentHashMapV8 map;
- WriteThroughEntry(K key, V val, ConcurrentHashMapV8 map) {
- super(key, val);
- this.map = map;
- }
-
/**
* Sets our entry's value and writes through to the map. The
- * value to return is somewhat arbitrary here. Since a
- * WriteThroughEntry does not necessarily track asynchronous
- * changes, the most recent "previous" value could be
- * different from what we return (or could even have been
- * removed in which case the put will re-establish). We do not
- * and cannot guarantee more.
+ * value to return is somewhat arbitrary here. Since we do not
+ * necessarily track asynchronous changes, the most recent
+ * "previous" value could be different from what we return (or
+ * could even have been removed in which case the put will
+ * re-establish). We do not and cannot guarantee more.
*/
public final V setValue(V value) {
if (value == null) throw new NullPointerException();
@@ -2854,48 +3278,711 @@ public class ConcurrentHashMapV8
}
}
+ /* ---------------- Serialization Support -------------- */
+
/**
- * Internal version of entry, that doesn't write though changes
+ * Stripped-down version of helper class used in previous version,
+ * declared for the sake of serialization compatibility
*/
- static final class SnapshotEntry extends MapEntry
- implements Map.Entry {
- SnapshotEntry(K key, V val) { super(key, val); }
- public final V setValue(V value) { // only locally update
- if (value == null) throw new NullPointerException();
- V v = val;
- val = value;
- return v;
+ static class Segment implements Serializable {
+ private static final long serialVersionUID = 2249069246763182397L;
+ final float loadFactor;
+ Segment(float lf) { this.loadFactor = lf; }
+ }
+
+ /**
+ * Saves the state of the {@code ConcurrentHashMapV8} instance to a
+ * stream (i.e., serializes it).
+ * @param s the stream
+ * @serialData
+ * the key (Object) and value (Object)
+ * 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)
+ throws java.io.IOException {
+ if (segments == null) { // for serialization compatibility
+ segments = (Segment[])
+ new Segment,?>[DEFAULT_CONCURRENCY_LEVEL];
+ for (int i = 0; i < segments.length; ++i)
+ segments[i] = new Segment(LOAD_FACTOR);
+ }
+ s.defaultWriteObject();
+ Traverser it = new Traverser(this);
+ Object v;
+ while ((v = it.advance()) != null) {
+ s.writeObject(it.nextKey);
+ s.writeObject(v);
+ }
+ s.writeObject(null);
+ s.writeObject(null);
+ segments = null; // throw away
+ }
+
+ /**
+ * Reconstitutes the instance from a stream (that is, deserializes it).
+ * @param s the stream
+ */
+ @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;
+ Node p = null;
+ for (;;) {
+ K k = (K) s.readObject();
+ V v = (V) s.readObject();
+ if (k != null && v != null) {
+ int h = spread(k.hashCode());
+ p = new Node(h, k, v, p);
+ ++size;
+ }
+ else
+ break;
+ }
+ if (p != null) {
+ boolean init = false;
+ int n;
+ if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
+ n = MAXIMUM_CAPACITY;
+ else {
+ int sz = (int)size;
+ n = tableSizeFor(sz + (sz >>> 1) + 1);
+ }
+ int sc = sizeCtl;
+ boolean collide = false;
+ if (n > sc &&
+ UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
+ try {
+ if (table == null) {
+ init = true;
+ Node[] tab = new Node[n];
+ int mask = n - 1;
+ while (p != null) {
+ int j = p.hash & mask;
+ Node next = p.next;
+ Node q = p.next = tabAt(tab, j);
+ setTabAt(tab, j, p);
+ if (!collide && q != null && q.hash == p.hash)
+ collide = true;
+ p = next;
+ }
+ table = tab;
+ counter.add(size);
+ sc = n - (n >>> 2);
+ }
+ } finally {
+ sizeCtl = sc;
+ }
+ if (collide) { // rescan and convert to TreeBins
+ Node[] tab = table;
+ for (int i = 0; i < tab.length; ++i) {
+ int c = 0;
+ for (Node e = tabAt(tab, i); e != null; e = e.next) {
+ if (++c > TREE_THRESHOLD &&
+ (e.key instanceof Comparable)) {
+ replaceWithTreeBin(tab, i, e.key);
+ break;
+ }
+ }
+ }
+ }
+ }
+ if (!init) { // Can only happen if unsafely published.
+ while (p != null) {
+ internalPut(p.key, p.val);
+ p = p.next;
+ }
+ }
}
}
+
+ // -------------------------------------------------------
+
+ // Sams
+ /** Interface describing a void action of one argument */
+ public interface Action { void apply(A a); }
+ /** Interface describing a void action of two arguments */
+ public interface BiAction { void apply(A a, B b); }
+ /** Interface describing a function of one argument */
+ public interface Fun { T apply(A a); }
+ /** Interface describing a function of two arguments */
+ public interface BiFun { T apply(A a, B b); }
+ /** Interface describing a function of no arguments */
+ public interface Generator { T apply(); }
+ /** Interface describing a function mapping its argument to a double */
+ public interface ObjectToDouble { double apply(A a); }
+ /** Interface describing a function mapping its argument to a long */
+ public interface ObjectToLong { long apply(A a); }
+ /** Interface describing a function mapping its argument to an int */
+ public interface ObjectToInt {int apply(A a); }
+ /** Interface describing a function mapping two arguments to a double */
+ public interface ObjectByObjectToDouble { double apply(A a, B b); }
+ /** Interface describing a function mapping two arguments to a long */
+ public interface ObjectByObjectToLong { long apply(A a, B b); }
+ /** Interface describing a function mapping two arguments to an int */
+ public interface ObjectByObjectToInt {int apply(A a, B b); }
+ /** Interface describing a function mapping a double to a double */
+ public interface DoubleToDouble { double apply(double a); }
+ /** Interface describing a function mapping a long to a long */
+ public interface LongToLong { long apply(long a); }
+ /** Interface describing a function mapping an int to an int */
+ public interface IntToInt { int apply(int a); }
+ /** Interface describing a function mapping two doubles to a double */
+ public interface DoubleByDoubleToDouble { double apply(double a, double b); }
+ /** Interface describing a function mapping two longs to a long */
+ public interface LongByLongToLong { long apply(long a, long b); }
+ /** Interface describing a function mapping two ints to an int */
+ public interface IntByIntToInt { int apply(int a, int b); }
+
+
+ // -------------------------------------------------------
+
+ /**
+ * Performs the given action for each (key, value).
+ *
+ * @param action the action
+ */
+ public void forEach(BiAction action) {
+ ForkJoinTasks.forEach
+ (this, action).invoke();
+ }
+
+ /**
+ * Performs the given action for each non-null transformation
+ * of each (key, 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).
+ * @param action the action
+ */
+ public void forEach(BiFun super K, ? super V, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEach
+ (this, transformer, action).invoke();
+ }
+
+ /**
+ * Returns a non-null result from applying the given search
+ * function on each (key, 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 (key, value), or null if none
+ */
+ public U search(BiFun super K, ? super V, ? extends U> searchFunction) {
+ return ForkJoinTasks.search
+ (this, searchFunction).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all (key, value) pairs 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 (key, value) pairs
+ */
+ public U reduce(BiFun super K, ? super V, ? extends U> transformer,
+ BiFun super U, ? super U, ? extends U> reducer) {
+ return ForkJoinTasks.reduce
+ (this, transformer, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all (key, value) pairs 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 (key, value) pairs
+ */
+ public double reduceToDouble(ObjectByObjectToDouble super K, ? super V> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceToDouble
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all (key, value) pairs 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 (key, value) pairs
+ */
+ public long reduceToLong(ObjectByObjectToLong super K, ? super V> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceToLong
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all (key, value) pairs 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 (key, value) pairs
+ */
+ public int reduceToInt(ObjectByObjectToInt super K, ? super V> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each key.
+ *
+ * @param action the action
+ */
+ public void forEachKey(Action action) {
+ ForkJoinTasks.forEachKey
+ (this, 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 forEachKey(Fun super K, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEachKey
+ (this, 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 searchKeys(Fun super K, ? extends U> searchFunction) {
+ return ForkJoinTasks.searchKeys
+ (this, 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 reduceKeys(BiFun super K, ? super K, ? extends K> reducer) {
+ return ForkJoinTasks.reduceKeys
+ (this, reducer).invoke();
+ }
+
+ /**
+ * Returns the result of accumulating the given transformation
+ * of all keys 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 keys
+ */
+ public U reduceKeys(Fun super K, ? extends U> transformer,
+ BiFun super U, ? super U, ? extends U> reducer) {
+ return ForkJoinTasks.reduceKeys
+ (this, transformer, 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 reduceKeysToDouble(ObjectToDouble super K> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceKeysToDouble
+ (this, 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 reduceKeysToLong(ObjectToLong super K> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceKeysToLong
+ (this, 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 reduceKeysToInt(ObjectToInt super K> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceKeysToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each value.
+ *
+ * @param action the action
+ */
+ public void forEachValue(Action action) {
+ ForkJoinTasks.forEachValue
+ (this, 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 forEachValue(Fun super V, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEachValue
+ (this, 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 searchValues(Fun super V, ? extends U> searchFunction) {
+ return ForkJoinTasks.searchValues
+ (this, 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 reduceValues(BiFun super V, ? super V, ? extends V> reducer) {
+ return ForkJoinTasks.reduceValues
+ (this, 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 reduceValues(Fun super V, ? extends U> transformer,
+ BiFun super U, ? super U, ? extends U> reducer) {
+ return ForkJoinTasks.reduceValues
+ (this, 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 reduceValuesToDouble(ObjectToDouble super V> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceValuesToDouble
+ (this, 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 reduceValuesToLong(ObjectToLong super V> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceValuesToLong
+ (this, 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 reduceValuesToInt(ObjectToInt super V> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceValuesToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
+ /**
+ * Performs the given action for each entry.
+ *
+ * @param action the action
+ */
+ public void forEachEntry(Action> action) {
+ ForkJoinTasks.forEachEntry
+ (this, 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 forEachEntry(Fun, ? extends U> transformer,
+ Action action) {
+ ForkJoinTasks.forEachEntry
+ (this, 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 searchEntries(Fun, ? extends U> searchFunction) {
+ return ForkJoinTasks.searchEntries
+ (this, 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 reduceEntries(BiFun, Map.Entry, ? extends Map.Entry> reducer) {
+ return ForkJoinTasks.reduceEntries
+ (this, 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 reduceEntries(Fun, ? extends U> transformer,
+ BiFun super U, ? super U, ? extends U> reducer) {
+ return ForkJoinTasks.reduceEntries
+ (this, 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 reduceEntriesToDouble(ObjectToDouble> transformer,
+ double basis,
+ DoubleByDoubleToDouble reducer) {
+ return ForkJoinTasks.reduceEntriesToDouble
+ (this, 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 reduceEntriesToLong(ObjectToLong> transformer,
+ long basis,
+ LongByLongToLong reducer) {
+ return ForkJoinTasks.reduceEntriesToLong
+ (this, 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 reduceEntriesToInt(ObjectToInt> transformer,
+ int basis,
+ IntByIntToInt reducer) {
+ return ForkJoinTasks.reduceEntriesToInt
+ (this, transformer, basis, reducer).invoke();
+ }
+
/* ----------------Views -------------- */
/**
- * Base class for views. This is done mainly to allow adding
- * customized parallel traversals (not yet implemented.)
+ * Base class for views.
*/
- static abstract class MapView {
+ static abstract class CHMView {
final ConcurrentHashMapV8 map;
- MapView(ConcurrentHashMapV8 map) { this.map = 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 Iterator> iter();
+ 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.longSize();
+ 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 = iter();
+ Iterator> it = iterator();
while (it.hasNext()) {
if (i == n) {
if (n >= MAX_ARRAY_SIZE)
@@ -2911,9 +3998,8 @@ public class ConcurrentHashMapV8
return (i == n) ? r : Arrays.copyOf(r, i);
}
- @SuppressWarnings("unchecked")
- public final T[] toArray(T[] a) {
- long sz = map.longSize();
+ @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;
@@ -2922,7 +4008,7 @@ public class ConcurrentHashMapV8
.newInstance(a.getClass().getComponentType(), m);
int n = r.length;
int i = 0;
- Iterator> it = iter();
+ Iterator> it = iterator();
while (it.hasNext()) {
if (i == n) {
if (n >= MAX_ARRAY_SIZE)
@@ -2944,7 +4030,7 @@ public class ConcurrentHashMapV8
public final int hashCode() {
int h = 0;
- for (Iterator> it = iter(); it.hasNext();)
+ for (Iterator> it = iterator(); it.hasNext();)
h += it.next().hashCode();
return h;
}
@@ -2952,7 +4038,7 @@ public class ConcurrentHashMapV8
public final String toString() {
StringBuilder sb = new StringBuilder();
sb.append('[');
- Iterator> it = iter();
+ Iterator> it = iterator();
if (it.hasNext()) {
for (;;) {
Object e = it.next();
@@ -2978,7 +4064,7 @@ public class ConcurrentHashMapV8
public final boolean removeAll(Collection> c) {
boolean modified = false;
- for (Iterator> it = iter(); it.hasNext();) {
+ for (Iterator> it = iterator(); it.hasNext();) {
if (c.contains(it.next())) {
it.remove();
modified = true;
@@ -2989,7 +4075,7 @@ public class ConcurrentHashMapV8
public final boolean retainAll(Collection> c) {
boolean modified = false;
- for (Iterator> it = iter(); it.hasNext();) {
+ for (Iterator> it = iterator(); it.hasNext();) {
if (!c.contains(it.next())) {
it.remove();
modified = true;
@@ -3000,22 +4086,66 @@ public class ConcurrentHashMapV8
}
- static final class KeySet extends MapView implements Set {
- KeySet(ConcurrentHashMapV8 map) { super(map); }
- public final boolean contains(Object o) { return map.containsKey(o); }
- public final boolean remove(Object o) { return map.remove(o) != null; }
-
- public final Iterator iterator() {
- return new KeyIterator(map);
- }
- final Iterator> iter() {
- return new KeyIterator(map);
- }
- public final boolean add(K e) {
- throw new UnsupportedOperationException();
+ /**
+ * 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;
}
- public final boolean addAll(Collection extends K> c) {
- throw new UnsupportedOperationException();
+
+ /**
+ * 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.internalPutIfAbsent(e, v) == null;
+ }
+ public boolean addAll(Collection extends K> 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;
@@ -3023,13 +4153,137 @@ public class ConcurrentHashMapV8