entrySet;
/* ---------------- Public operations -------------- */
/**
* Creates a new, empty map with the default initial table size (16).
*/
public ConcurrentHashMapV8() {
}
/**
* Creates a new, empty map with an initial table size
* accommodating the specified number of elements without the need
* to dynamically resize.
*
* @param initialCapacity The implementation performs internal
* sizing to accommodate this many elements.
* @throws IllegalArgumentException if the initial capacity of
* elements is negative
*/
public ConcurrentHashMapV8(int initialCapacity) {
if (initialCapacity < 0)
throw new IllegalArgumentException();
int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
MAXIMUM_CAPACITY :
tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
this.sizeCtl = cap;
}
/**
* Creates a new map with the same mappings as the given map.
*
* @param m the map
*/
public ConcurrentHashMapV8(Map extends K, ? extends V> m) {
this.sizeCtl = DEFAULT_CAPACITY;
putAll(m);
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}) and
* initial table density ({@code loadFactor}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @throws IllegalArgumentException if the initial capacity of
* elements is negative or the load factor is nonpositive
*
* @since 1.6
*/
public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
this(initialCapacity, loadFactor, 1);
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}), table
* density ({@code loadFactor}), and number of concurrently
* updating threads ({@code concurrencyLevel}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @param concurrencyLevel the estimated number of concurrently
* updating threads. The implementation may use this value as
* a sizing hint.
* @throws IllegalArgumentException if the initial capacity is
* negative or the load factor or concurrencyLevel are
* nonpositive
*/
public ConcurrentHashMapV8(int initialCapacity,
float loadFactor, int concurrencyLevel) {
if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
throw new IllegalArgumentException();
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);
this.sizeCtl = cap;
}
// Original (since JDK1.2) Map methods
/**
* {@inheritDoc}
*/
public int size() {
long n = sumCount();
return ((n < 0L) ? 0 :
(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
(int)n);
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
return sumCount() <= 0L; // ignore transient negative values
}
/**
* Returns the value to which the specified key is mapped,
* or {@code null} if this map contains no mapping for the key.
*
* More formally, if this map contains a mapping from a key
* {@code k} to a value {@code v} such that {@code key.equals(k)},
* then this method returns {@code v}; otherwise it returns
* {@code null}. (There can be at most one such mapping.)
*
* @throws NullPointerException if the specified key is null
*/
public V get(Object key) {
Node[] tab; Node e, p; int n, eh; K ek;
int h = spread(key.hashCode());
if ((tab = table) != null && (n = tab.length) > 0 &&
(e = tabAt(tab, (n - 1) & h)) != null) {
if ((eh = e.hash) == h) {
if ((ek = e.key) == key || (ek != null && key.equals(ek)))
return e.val;
}
else if (eh < 0)
return (p = e.find(h, key)) != null ? p.val : null;
while ((e = e.next) != null) {
if (e.hash == h &&
((ek = e.key) == key || (ek != null && key.equals(ek))))
return e.val;
}
}
return null;
}
/**
* Tests if the specified object is a key in this table.
*
* @param key possible key
* @return {@code true} if and only if the specified object
* is a key in this table, as determined by the
* {@code equals} method; {@code false} otherwise
* @throws NullPointerException if the specified key is null
*/
public boolean containsKey(Object key) {
return get(key) != null;
}
/**
* Returns {@code true} if this map maps one or more keys to the
* specified value. Note: This method may require a full traversal
* of the map, and is much slower than method {@code containsKey}.
*
* @param value value whose presence in this map is to be tested
* @return {@code true} if this map maps one or more keys to the
* specified value
* @throws NullPointerException if the specified value is null
*/
public boolean containsValue(Object value) {
if (value == null)
throw new NullPointerException();
Node[] t;
if ((t = table) != null) {
Traverser it = new Traverser(t, t.length, 0, t.length);
for (Node p; (p = it.advance()) != null; ) {
V v;
if ((v = p.val) == value || (v != null && value.equals(v)))
return true;
}
}
return false;
}
/**
* Maps the specified key to the specified value in this table.
* Neither the key nor the value can be null.
*
* The value can be retrieved by calling the {@code get} method
* with a key that is equal to the original key.
*
* @param key key with which the specified value is to be associated
* @param value value to be associated with the specified key
* @return the previous value associated with {@code key}, or
* {@code null} if there was no mapping for {@code key}
* @throws NullPointerException if the specified key or value is null
*/
public V put(K key, V value) {
return putVal(key, value, false);
}
/** Implementation for put and putIfAbsent */
final V putVal(K key, V value, boolean onlyIfAbsent) {
if (key == null || value == null) throw new NullPointerException();
int hash = spread(key.hashCode());
int binCount = 0;
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
if (casTabAt(tab, i, null,
new Node(hash, key, value, null)))
break; // no lock when adding to empty bin
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
V oldVal = null;
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node e = f;; ++binCount) {
K ek;
if (e.hash == hash &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
oldVal = e.val;
if (!onlyIfAbsent)
e.val = value;
break;
}
Node pred = e;
if ((e = e.next) == null) {
pred.next = new Node(hash, key,
value, null);
break;
}
}
}
else if (f instanceof TreeBin) {
Node p;
binCount = 2;
if ((p = ((TreeBin)f).putTreeVal(hash, key,
value)) != null) {
oldVal = p.val;
if (!onlyIfAbsent)
p.val = value;
}
}
}
}
if (binCount != 0) {
if (binCount >= TREEIFY_THRESHOLD)
treeifyBin(tab, i);
if (oldVal != null)
return oldVal;
break;
}
}
}
addCount(1L, binCount);
return null;
}
/**
* Copies all of the mappings from the specified map to this one.
* These mappings replace any mappings that this map had for any of the
* keys currently in the specified map.
*
* @param m mappings to be stored in this map
*/
public void putAll(Map extends K, ? extends V> m) {
tryPresize(m.size());
for (Map.Entry extends K, ? extends V> e : m.entrySet())
putVal(e.getKey(), e.getValue(), false);
}
/**
* Removes the key (and its corresponding value) from this map.
* This method does nothing if the key is not in the map.
*
* @param key the key that needs to be removed
* @return the previous value associated with {@code key}, or
* {@code null} if there was no mapping for {@code key}
* @throws NullPointerException if the specified key is null
*/
public V remove(Object key) {
return replaceNode(key, null, null);
}
/**
* Implementation for the four public remove/replace methods:
* Replaces node value with v, conditional upon match of cv if
* non-null. If resulting value is null, delete.
*/
final V replaceNode(Object key, V value, Object cv) {
int hash = spread(key.hashCode());
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0 ||
(f = tabAt(tab, i = (n - 1) & hash)) == null)
break;
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
V oldVal = null;
boolean validated = false;
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
validated = true;
for (Node e = f, pred = null;;) {
K ek;
if (e.hash == hash &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
V ev = e.val;
if (cv == null || cv == ev ||
(ev != null && cv.equals(ev))) {
oldVal = ev;
if (value != null)
e.val = value;
else if (pred != null)
pred.next = e.next;
else
setTabAt(tab, i, e.next);
}
break;
}
pred = e;
if ((e = e.next) == null)
break;
}
}
else if (f instanceof TreeBin) {
validated = true;
TreeBin t = (TreeBin)f;
TreeNode r, p;
if ((r = t.root) != null &&
(p = r.findTreeNode(hash, key, null)) != null) {
V pv = p.val;
if (cv == null || cv == pv ||
(pv != null && cv.equals(pv))) {
oldVal = pv;
if (value != null)
p.val = value;
else if (t.removeTreeNode(p))
setTabAt(tab, i, untreeify(t.first));
}
}
}
}
}
if (validated) {
if (oldVal != null) {
if (value == null)
addCount(-1L, -1);
return oldVal;
}
break;
}
}
}
return null;
}
/**
* Removes all of the mappings from this map.
*/
public void clear() {
long delta = 0L; // negative number of deletions
int i = 0;
Node[] tab = table;
while (tab != null && i < tab.length) {
int fh;
Node f = tabAt(tab, i);
if (f == null)
++i;
else if ((fh = f.hash) == MOVED) {
tab = helpTransfer(tab, f);
i = 0; // restart
}
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
Node p = (fh >= 0 ? f :
(f instanceof TreeBin) ?
((TreeBin)f).first : null);
while (p != null) {
--delta;
p = p.next;
}
setTabAt(tab, i++, null);
}
}
}
}
if (delta != 0L)
addCount(delta, -1);
}
/**
* 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.
*
* 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 KeySetView keySet() {
KeySetView ks;
return (ks = keySet) != null ? ks : (keySet = new KeySetView(this, null));
}
/**
* 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.
*
* @return the collection view
*/
public Collection values() {
ValuesView vs;
return (vs = values) != null ? vs : (values = new ValuesView(this));
}
/**
* Returns a {@link Set} view of the mappings 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 the map,
* via the {@code Iterator.remove}, {@code Set.remove},
* {@code removeAll}, {@code retainAll}, and {@code clear}
* 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.
*
* @return the set view
*/
public Set> entrySet() {
EntrySetView es;
return (es = entrySet) != null ? es : (entrySet = new EntrySetView(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()}.
*
* @return the hash code value for this map
*/
public int hashCode() {
int h = 0;
Node[] t;
if ((t = table) != null) {
Traverser it = new Traverser(t, t.length, 0, t.length);
for (Node p; (p = it.advance()) != null; )
h += p.key.hashCode() ^ p.val.hashCode();
}
return h;
}
/**
* Returns a string representation of this map. The string
* representation consists of a list of key-value mappings (in no
* particular order) enclosed in braces ("{@code {}}"). Adjacent
* mappings are separated by the characters {@code ", "} (comma
* and space). Each key-value mapping is rendered as the key
* followed by an equals sign ("{@code =}") followed by the
* associated value.
*
* @return a string representation of this map
*/
public String toString() {
Node[] t;
int f = (t = table) == null ? 0 : t.length;
Traverser it = new Traverser(t, f, 0, f);
StringBuilder sb = new StringBuilder();
sb.append('{');
Node p;
if ((p = it.advance()) != null) {
for (;;) {
K k = p.key;
V v = p.val;
sb.append(k == this ? "(this Map)" : k);
sb.append('=');
sb.append(v == this ? "(this Map)" : v);
if ((p = it.advance()) == null)
break;
sb.append(',').append(' ');
}
}
return sb.append('}').toString();
}
/**
* Compares the specified object with this map for equality.
* Returns {@code true} if the given object is a map with the same
* mappings as this map. This operation may return misleading
* results if either map is concurrently modified during execution
* of this method.
*
* @param o object to be compared for equality with this map
* @return {@code true} if the specified object is equal to this map
*/
public boolean equals(Object o) {
if (o != this) {
if (!(o instanceof Map))
return false;
Map,?> m = (Map,?>) o;
Node[] t;
int f = (t = table) == null ? 0 : t.length;
Traverser it = new Traverser(t, f, 0, f);
for (Node p; (p = it.advance()) != null; ) {
V val = p.val;
Object v = m.get(p.key);
if (v == null || (v != val && !v.equals(val)))
return false;
}
for (Map.Entry,?> e : m.entrySet()) {
Object mk, mv, v;
if ((mk = e.getKey()) == null ||
(mv = e.getValue()) == null ||
(v = get(mk)) == null ||
(mv != v && !mv.equals(v)))
return false;
}
}
return true;
}
/**
* Stripped-down version of helper class used in previous version,
* declared for the sake of serialization compatibility
*/
static class Segment extends ReentrantLock 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
* @throws java.io.IOException if an I/O error occurs
* @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.
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
// For serialization compatibility
// Emulate segment calculation from previous version of this class
int sshift = 0;
int ssize = 1;
while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
++sshift;
ssize <<= 1;
}
int segmentShift = 32 - sshift;
int segmentMask = ssize - 1;
@SuppressWarnings("unchecked") Segment[] segments = (Segment[])
new Segment,?>[DEFAULT_CONCURRENCY_LEVEL];
for (int i = 0; i < segments.length; ++i)
segments[i] = new Segment(LOAD_FACTOR);
s.putFields().put("segments", segments);
s.putFields().put("segmentShift", segmentShift);
s.putFields().put("segmentMask", segmentMask);
s.writeFields();
Node[] t;
if ((t = table) != null) {
Traverser it = new Traverser(t, t.length, 0, t.length);
for (Node p; (p = it.advance()) != null; ) {
s.writeObject(p.key);
s.writeObject(p.val);
}
}
s.writeObject(null);
s.writeObject(null);
segments = null; // throw away
}
/**
* Reconstitutes the instance from a stream (that is, deserializes it).
* @param s the stream
* @throws ClassNotFoundException if the class of a serialized object
* could not be found
* @throws java.io.IOException if an I/O error occurs
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
/*
* To improve performance in typical cases, we create nodes
* while reading, then place in table once size is known.
* However, we must also validate uniqueness and deal with
* overpopulated bins while doing so, which requires
* specialized versions of putVal mechanics.
*/
sizeCtl = -1; // force exclusion for table construction
s.defaultReadObject();
long size = 0L;
Node p = null;
for (;;) {
@SuppressWarnings("unchecked") K k = (K) s.readObject();
@SuppressWarnings("unchecked") V v = (V) s.readObject();
if (k != null && v != null) {
p = new Node(spread(k.hashCode()), k, v, p);
++size;
}
else
break;
}
if (size == 0L)
sizeCtl = 0;
else {
int n;
if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
n = MAXIMUM_CAPACITY;
else {
int sz = (int)size;
n = tableSizeFor(sz + (sz >>> 1) + 1);
}
@SuppressWarnings("unchecked")
Node[] tab = (Node[])new Node,?>[n];
int mask = n - 1;
long added = 0L;
while (p != null) {
boolean insertAtFront;
Node next = p.next, first;
int h = p.hash, j = h & mask;
if ((first = tabAt(tab, j)) == null)
insertAtFront = true;
else {
K k = p.key;
if (first.hash < 0) {
TreeBin t = (TreeBin)first;
if (t.putTreeVal(h, k, p.val) == null)
++added;
insertAtFront = false;
}
else {
int binCount = 0;
insertAtFront = true;
Node q; K qk;
for (q = first; q != null; q = q.next) {
if (q.hash == h &&
((qk = q.key) == k ||
(qk != null && k.equals(qk)))) {
insertAtFront = false;
break;
}
++binCount;
}
if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
insertAtFront = false;
++added;
p.next = first;
TreeNode hd = null, tl = null;
for (q = p; q != null; q = q.next) {
TreeNode t = new TreeNode
(q.hash, q.key, q.val, null, null);
if ((t.prev = tl) == null)
hd = t;
else
tl.next = t;
tl = t;
}
setTabAt(tab, j, new TreeBin(hd));
}
}
}
if (insertAtFront) {
++added;
p.next = first;
setTabAt(tab, j, p);
}
p = next;
}
table = tab;
sizeCtl = n - (n >>> 2);
baseCount = added;
}
}
// ConcurrentMap methods
/**
* {@inheritDoc}
*
* @return the previous value associated with the specified key,
* or {@code null} if there was no mapping for the key
* @throws NullPointerException if the specified key or value is null
*/
public V putIfAbsent(K key, V value) {
return putVal(key, value, true);
}
/**
* {@inheritDoc}
*
* @throws NullPointerException if the specified key is null
*/
public boolean remove(Object key, Object value) {
if (key == null)
throw new NullPointerException();
return value != null && replaceNode(key, null, value) != null;
}
/**
* {@inheritDoc}
*
* @throws NullPointerException if any of the arguments are null
*/
public boolean replace(K key, V oldValue, V newValue) {
if (key == null || oldValue == null || newValue == null)
throw new NullPointerException();
return replaceNode(key, newValue, oldValue) != null;
}
/**
* {@inheritDoc}
*
* @return the previous value associated with the specified key,
* or {@code null} if there was no mapping for the key
* @throws NullPointerException if the specified key or value is null
*/
public V replace(K key, V value) {
if (key == null || value == null)
throw new NullPointerException();
return replaceNode(key, value, null);
}
// Overrides of JDK8+ Map extension method defaults
/**
* Returns the value to which the specified key is mapped, or the
* given default value if this map contains no mapping for the
* key.
*
* @param key the key whose associated value is to be returned
* @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 default value
* @throws NullPointerException if the specified key is null
*/
public V getOrDefault(Object key, V defaultValue) {
V v;
return (v = get(key)) == null ? defaultValue : v;
}
public void forEach(BiAction super K, ? super V> action) {
if (action == null) throw new NullPointerException();
Node[] t;
if ((t = table) != null) {
Traverser it = new Traverser(t, t.length, 0, t.length);
for (Node p; (p = it.advance()) != null; ) {
action.apply(p.key, p.val);
}
}
}
public void replaceAll(BiFun super K, ? super V, ? extends V> function) {
if (function == null) throw new NullPointerException();
Node[] t;
if ((t = table) != null) {
Traverser it = new Traverser(t, t.length, 0, t.length);
for (Node p; (p = it.advance()) != null; ) {
V oldValue = p.val;
for (K key = p.key;;) {
V newValue = function.apply(key, oldValue);
if (newValue == null)
throw new NullPointerException();
if (replaceNode(key, newValue, oldValue) != null ||
(oldValue = get(key)) == null)
break;
}
}
}
}
/**
* If the specified key is not already associated with a value,
* attempts to compute its value using the given mapping function
* and enters it into this map unless {@code null}. The entire
* method invocation is performed atomically, so the function is
* applied at most once per key. 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.
*
* @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, 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
*/
public V computeIfAbsent(K key, Fun super K, ? extends V> mappingFunction) {
if (key == null || mappingFunction == null)
throw new NullPointerException();
int h = spread(key.hashCode());
V val = null;
int binCount = 0;
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
Node r = new ReservationNode();
synchronized (r) {
if (casTabAt(tab, i, null, r)) {
binCount = 1;
Node node = null;
try {
if ((val = mappingFunction.apply(key)) != null)
node = new Node(h, key, val, null);
} finally {
setTabAt(tab, i, node);
}
}
}
if (binCount != 0)
break;
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
boolean added = false;
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node e = f;; ++binCount) {
K ek; V ev;
if (e.hash == h &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
val = e.val;
break;
}
Node pred = e;
if ((e = e.next) == null) {
if ((val = mappingFunction.apply(key)) != null) {
added = true;
pred.next = new Node(h, key, val, null);
}
break;
}
}
}
else if (f instanceof TreeBin) {
binCount = 2;
TreeBin t = (TreeBin)f;
TreeNode r, p;
if ((r = t.root) != null &&
(p = r.findTreeNode(h, key, null)) != null)
val = p.val;
else if ((val = mappingFunction.apply(key)) != null) {
added = true;
t.putTreeVal(h, key, val);
}
}
}
}
if (binCount != 0) {
if (binCount >= TREEIFY_THRESHOLD)
treeifyBin(tab, i);
if (!added)
return val;
break;
}
}
}
if (val != null)
addCount(1L, binCount);
return val;
}
/**
* If the value for the specified key is present, attempts to
* compute a new mapping given the key and its current mapped
* value. The entire method invocation is performed atomically.
* 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.
*
* @param key key with which a value may 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
*/
public V computeIfPresent(K key, BiFun super K, ? super V, ? extends V> remappingFunction) {
if (key == null || remappingFunction == null)
throw new NullPointerException();
int h = spread(key.hashCode());
V val = null;
int delta = 0;
int binCount = 0;
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
break;
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node e = f, pred = null;; ++binCount) {
K ek;
if (e.hash == h &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
val = remappingFunction.apply(key, e.val);
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)
break;
}
}
else if (f instanceof TreeBin) {
binCount = 2;
TreeBin t = (TreeBin)f;
TreeNode r, p;
if ((r = t.root) != null &&
(p = r.findTreeNode(h, key, null)) != null) {
val = remappingFunction.apply(key, p.val);
if (val != null)
p.val = val;
else {
delta = -1;
if (t.removeTreeNode(p))
setTabAt(tab, i, untreeify(t.first));
}
}
}
}
}
if (binCount != 0)
break;
}
}
if (delta != 0)
addCount((long)delta, binCount);
return val;
}
/**
* Attempts to compute a mapping for the specified key and its
* current mapped value (or {@code null} if there is no current
* mapping). The entire method invocation is performed atomically.
* 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.
*
* @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
*/
public V compute(K key,
BiFun super K, ? super V, ? extends V> remappingFunction) {
if (key == null || remappingFunction == null)
throw new NullPointerException();
int h = spread(key.hashCode());
V val = null;
int delta = 0;
int binCount = 0;
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
Node r = new ReservationNode();
synchronized (r) {
if (casTabAt(tab, i, null, r)) {
binCount = 1;
Node node = null;
try {
if ((val = remappingFunction.apply(key, null)) != null) {
delta = 1;
node = new Node(h, key, val, null);
}
} finally {
setTabAt(tab, i, node);
}
}
}
if (binCount != 0)
break;
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node e = f, pred = null;; ++binCount) {
K ek;
if (e.hash == h &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
val = remappingFunction.apply(key, e.val);
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 = remappingFunction.apply(key, null);
if (val != null) {
delta = 1;
pred.next =
new Node(h, key, val, null);
}
break;
}
}
}
else if (f instanceof TreeBin) {
binCount = 1;
TreeBin t = (TreeBin)f;
TreeNode r, p;
if ((r = t.root) != null)
p = r.findTreeNode(h, key, null);
else
p = null;
V pv = (p == null) ? null : p.val;
val = remappingFunction.apply(key, pv);
if (val != null) {
if (p != null)
p.val = val;
else {
delta = 1;
t.putTreeVal(h, key, val);
}
}
else if (p != null) {
delta = -1;
if (t.removeTreeNode(p))
setTabAt(tab, i, untreeify(t.first));
}
}
}
}
if (binCount != 0) {
if (binCount >= TREEIFY_THRESHOLD)
treeifyBin(tab, i);
break;
}
}
}
if (delta != 0)
addCount((long)delta, binCount);
return val;
}
/**
* If the specified key is not already associated with a
* (non-null) value, associates it with the given value.
* Otherwise, replaces the value with the results of the given
* remapping function, or removes if {@code null}. The entire
* method invocation is performed atomically. 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.
*
* @param key key with which the specified value is to be associated
* @param value the value to use if absent
* @param remappingFunction the function to recompute a value if present
* @return the new value associated with the specified key, or null if none
* @throws NullPointerException if the specified key or the
* remappingFunction is null
* @throws RuntimeException or Error if the remappingFunction does so,
* in which case the mapping is unchanged
*/
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();
int h = spread(key.hashCode());
V val = null;
int delta = 0;
int binCount = 0;
for (Node[] tab = table;;) {
Node f; int n, i, fh;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
if (casTabAt(tab, i, null, new Node(h, key, value, null))) {
delta = 1;
val = value;
break;
}
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
if (fh >= 0) {
binCount = 1;
for (Node e = f, pred = null;; ++binCount) {
K ek;
if (e.hash == h &&
((ek = e.key) == key ||
(ek != null && key.equals(ek)))) {
val = remappingFunction.apply(e.val, value);
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) {
delta = 1;
val = value;
pred.next =
new Node(h, key, val, null);
break;
}
}
}
else if (f instanceof TreeBin) {
binCount = 2;
TreeBin t = (TreeBin)f;
TreeNode r = t.root;
TreeNode p = (r == null) ? null :
r.findTreeNode(h, key, null);
val = (p == null) ? value :
remappingFunction.apply(p.val, value);
if (val != null) {
if (p != null)
p.val = val;
else {
delta = 1;
t.putTreeVal(h, key, val);
}
}
else if (p != null) {
delta = -1;
if (t.removeTreeNode(p))
setTabAt(tab, i, untreeify(t.first));
}
}
}
}
if (binCount != 0) {
if (binCount >= TREEIFY_THRESHOLD)
treeifyBin(tab, i);
break;
}
}
}
if (delta != 0)
addCount((long)delta, binCount);
return val;
}
// Hashtable legacy methods
/**
* Legacy method testing if some key maps into the specified value
* in this table. This method is identical in functionality to
* {@link #containsValue(Object)}, and exists solely to ensure
* full compatibility with class {@link java.util.Hashtable},
* which supported this method prior to introduction of the
* Java Collections framework.
*
* @param value a value to search for
* @return {@code true} if and only if some key maps to the
* {@code value} argument in this table as
* determined by the {@code equals} method;
* {@code false} otherwise
* @throws NullPointerException if the specified value is null
*/
@Deprecated public boolean contains(Object value) {
return containsValue(value);
}
/**
* Returns an enumeration of the keys in this table.
*
* @return an enumeration of the keys in this table
* @see #keySet()
*/
public Enumeration keys() {
Node[] t;
int f = (t = table) == null ? 0 : t.length;
return new KeyIterator(t, f, 0, f, this);
}
/**
* Returns an enumeration of the values in this table.
*
* @return an enumeration of the values in this table
* @see #values()
*/
public Enumeration elements() {
Node[] t;
int f = (t = table) == null ? 0 : t.length;
return new ValueIterator(t, f, 0, f, this);
}
// ConcurrentHashMapV8-only methods
/**
* 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 an estimate; the actual count may differ if
* there are concurrent insertions or removals.
*
* @return the number of mappings
* @since 1.8
*/
public long mappingCount() {
long n = sumCount();
return (n < 0L) ? 0L : n; // ignore transient negative values
}
/**
* Creates a new {@link Set} backed by a ConcurrentHashMapV8
* from the given type to {@code Boolean.TRUE}.
*
* @return the new set
* @since 1.8
*/
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.
* @return the new set
* @throws IllegalArgumentException if the initial capacity of
* elements is negative
* @since 1.8
*/
public static KeySetView newKeySet(int initialCapacity) {
return new KeySetView
(new ConcurrentHashMapV8(initialCapacity), Boolean.TRUE);
}
/**
* 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(Collection)}).
* 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);
}
/* ---------------- Special Nodes -------------- */
/**
* A node inserted at head of bins during transfer operations.
*/
static final class ForwardingNode extends Node {
final Node[] nextTable;
ForwardingNode(Node[] tab) {
super(MOVED, null, null, null);
this.nextTable = tab;
}
Node find(int h, Object k) {
// loop to avoid arbitrarily deep recursion on forwarding nodes
outer: for (Node[] tab = nextTable;;) {
Node e; int n;
if (k == null || tab == null || (n = tab.length) == 0 ||
(e = tabAt(tab, (n - 1) & h)) == null)
return null;
for (;;) {
int eh; K ek;
if ((eh = e.hash) == h &&
((ek = e.key) == k || (ek != null && k.equals(ek))))
return e;
if (eh < 0) {
if (e instanceof ForwardingNode) {
tab = ((ForwardingNode)e).nextTable;
continue outer;
}
else
return e.find(h, k);
}
if ((e = e.next) == null)
return null;
}
}
}
}
/**
* A place-holder node used in computeIfAbsent and compute
*/
static final class ReservationNode extends Node {
ReservationNode() {
super(RESERVED, null, null, null);
}
Node find(int h, Object k) {
return null;
}
}
/* ---------------- Table Initialization and Resizing -------------- */
/**
* Initializes table, using the size recorded in sizeCtl.
*/
private final Node[] initTable() {
Node[] tab; int sc;
while ((tab = table) == null || tab.length == 0) {
if ((sc = sizeCtl) < 0)
Thread.yield(); // lost initialization race; just spin
else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if ((tab = table) == null || tab.length == 0) {
int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
@SuppressWarnings("unchecked")
Node[] nt = (Node[])new Node,?>[n];
table = tab = nt;
sc = n - (n >>> 2);
}
} finally {
sizeCtl = sc;
}
break;
}
}
return tab;
}
/**
* Adds to count, and if table is too small and not already
* resizing, initiates transfer. If already resizing, helps
* perform transfer if work is available. Rechecks occupancy
* after a transfer to see if another resize is already needed
* because resizings are lagging additions.
*
* @param x the count to add
* @param check if <0, don't check resize, if <= 1 only check if uncontended
*/
private final void addCount(long x, int check) {
CounterCell[] as; long b, s;
if ((as = counterCells) != null ||
!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
CounterHashCode hc; CounterCell a; long v; int m;
boolean uncontended = true;
if ((hc = threadCounterHashCode.get()) == null ||
as == null || (m = as.length - 1) < 0 ||
(a = as[m & hc.code]) == null ||
!(uncontended =
U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
fullAddCount(x, hc, uncontended);
return;
}
if (check <= 1)
return;
s = sumCount();
}
if (check >= 0) {
Node[] tab, nt; int sc;
while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
tab.length < MAXIMUM_CAPACITY) {
if (sc < 0) {
if (sc == -1 || transferIndex <= transferOrigin ||
(nt = nextTable) == null)
break;
if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
transfer(tab, nt);
}
else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
transfer(tab, null);
s = sumCount();
}
}
}
/**
* Helps transfer if a resize is in progress.
*/
final Node[] helpTransfer(Node[] tab, Node f) {
Node[] nextTab; int sc;
if ((f instanceof ForwardingNode) &&
(nextTab = ((ForwardingNode)f).nextTable) != null) {
if (nextTab == nextTable && tab == table &&
transferIndex > transferOrigin && (sc = sizeCtl) < -1 &&
U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
transfer(tab, nextTab);
return nextTab;
}
return table;
}
/**
* Tries to presize table to accommodate the given number of elements.
*
* @param size number of elements (doesn't need to be perfectly accurate)
*/
private final void tryPresize(int size) {
int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
tableSizeFor(size + (size >>> 1) + 1);
int sc;
while ((sc = sizeCtl) >= 0) {
Node[] tab = table; int n;
if (tab == null || (n = tab.length) == 0) {
n = (sc > c) ? sc : c;
if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
try {
if (table == tab) {
@SuppressWarnings("unchecked")
Node[] nt = (Node[])new Node,?>[n];
table = nt;
sc = n - (n >>> 2);
}
} finally {
sizeCtl = sc;
}
}
}
else if (c <= sc || n >= MAXIMUM_CAPACITY)
break;
else if (tab == table &&
U.compareAndSwapInt(this, SIZECTL, sc, -2))
transfer(tab, null);
}
}
/**
* Moves and/or copies the nodes in each bin to new table. See
* above for explanation.
*/
private final void transfer(Node[] tab, Node[] nextTab) {
int n = tab.length, stride;
if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
stride = MIN_TRANSFER_STRIDE; // subdivide range
if (nextTab == null) { // initiating
try {
@SuppressWarnings("unchecked")
Node[] nt = (Node[])new Node,?>[n << 1];
nextTab = nt;
} catch (Throwable ex) { // try to cope with OOME
sizeCtl = Integer.MAX_VALUE;
return;
}
nextTable = nextTab;
transferOrigin = n;
transferIndex = n;
ForwardingNode rev = new ForwardingNode(tab);
for (int k = n; k > 0;) { // progressively reveal ready slots
int nextk = (k > stride) ? k - stride : 0;
for (int m = nextk; m < k; ++m)
nextTab[m] = rev;
for (int m = n + nextk; m < n + k; ++m)
nextTab[m] = rev;
U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
}
}
int nextn = nextTab.length;
ForwardingNode fwd = new ForwardingNode(nextTab);
boolean advance = true;
boolean finishing = false; // to ensure sweep before committing nextTab
for (int i = 0, bound = 0;;) {
int nextIndex, nextBound, fh; Node f;
while (advance) {
if (--i >= bound || finishing)
advance = false;
else if ((nextIndex = transferIndex) <= transferOrigin) {
i = -1;
advance = false;
}
else if (U.compareAndSwapInt
(this, TRANSFERINDEX, nextIndex,
nextBound = (nextIndex > stride ?
nextIndex - stride : 0))) {
bound = nextBound;
i = nextIndex - 1;
advance = false;
}
}
if (i < 0 || i >= n || i + n >= nextn) {
if (finishing) {
nextTable = null;
table = nextTab;
sizeCtl = (n << 1) - (n >>> 1);
return;
}
for (int sc;;) {
if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
if (sc != -1)
return;
finishing = advance = true;
i = n; // recheck before commit
break;
}
}
}
else if ((f = tabAt(tab, i)) == null) {
if (casTabAt(tab, i, null, fwd)) {
setTabAt(nextTab, i, null);
setTabAt(nextTab, i + n, null);
advance = true;
}
}
else if ((fh = f.hash) == MOVED)
advance = true; // already processed
else {
synchronized (f) {
if (tabAt(tab, i) == f) {
Node ln, hn;
if (fh >= 0) {
int runBit = fh & n;
Node lastRun = f;
for (Node p = f.next; p != null; p = p.next) {
int b = p.hash & n;
if (b != runBit) {
runBit = b;
lastRun = p;
}
}
if (runBit == 0) {
ln = lastRun;
hn = null;
}
else {
hn = lastRun;
ln = null;
}
for (Node p = f; p != lastRun; p = p.next) {
int ph = p.hash; K pk = p.key; V pv = p.val;
if ((ph & n) == 0)
ln = new Node(ph, pk, pv, ln);
else
hn = new Node(ph, pk, pv, hn);
}
setTabAt(nextTab, i, ln);
setTabAt(nextTab, i + n, hn);
setTabAt(tab, i, fwd);
advance = true;
}
else if (f instanceof TreeBin) {
TreeBin t = (TreeBin)f;
TreeNode lo = null, loTail = null;
TreeNode hi = null, hiTail = null;
int lc = 0, hc = 0;
for (Node e = t.first; e != null; e = e.next) {
int h = e.hash;
TreeNode p = new TreeNode
(h, e.key, e.val, null, null);
if ((h & n) == 0) {
if ((p.prev = loTail) == null)
lo = p;
else
loTail.next = p;
loTail = p;
++lc;
}
else {
if ((p.prev = hiTail) == null)
hi = p;
else
hiTail.next = p;
hiTail = p;
++hc;
}
}
ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
(hc != 0) ? new TreeBin(lo) : t;
hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
(lc != 0) ? new TreeBin(hi) : t;
setTabAt(nextTab, i, ln);
setTabAt(nextTab, i + n, hn);
setTabAt(tab, i, fwd);
advance = true;
}
}
}
}
}
}
/* ---------------- Conversion from/to TreeBins -------------- */
/**
* Replaces all linked nodes in bin at given index unless table is
* too small, in which case resizes instead.
*/
private final void treeifyBin(Node[] tab, int index) {
Node b; int n, sc;
if (tab != null) {
if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
if (tab == table && (sc = sizeCtl) >= 0 &&
U.compareAndSwapInt(this, SIZECTL, sc, -2))
transfer(tab, null);
}
else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
synchronized (b) {
if (tabAt(tab, index) == b) {
TreeNode hd = null, tl = null;
for (Node e = b; e != null; e = e.next) {
TreeNode p =
new TreeNode(e.hash, e.key, e.val,
null, null);
if ((p.prev = tl) == null)
hd = p;
else
tl.next = p;
tl = p;
}
setTabAt(tab, index, new TreeBin(hd));
}
}
}
}
}
/**
* Returns a list on non-TreeNodes replacing those in given list.
*/
static Node untreeify(Node b) {
Node hd = null, tl = null;
for (Node q = b; q != null; q = q.next) {
Node p = new Node(q.hash, q.key, q.val, null);
if (tl == null)
hd = p;
else
tl.next = p;
tl = p;
}
return hd;
}
/* ---------------- TreeNodes -------------- */
/**
* Nodes for use in TreeBins
*/
static final class TreeNode extends Node {
TreeNode parent; // red-black tree links
TreeNode left;
TreeNode right;
TreeNode prev; // needed to unlink next upon deletion
boolean red;
TreeNode(int hash, K key, V val, Node next,
TreeNode parent) {
super(hash, key, val, next);
this.parent = parent;
}
Node find(int h, Object k) {
return findTreeNode(h, k, null);
}
/**
* Returns the TreeNode (or null if not found) for the given key
* starting at given root.
*/
final TreeNode findTreeNode(int h, Object k, Class> kc) {
if (k != null) {
TreeNode p = this;
do {
int ph, dir; K pk; TreeNode q;
TreeNode pl = p.left, pr = p.right;
if ((ph = p.hash) > h)
p = pl;
else if (ph < h)
p = pr;
else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
return p;
else if (pl == null)
p = pr;
else if (pr == null)
p = pl;
else if ((kc != null ||
(kc = comparableClassFor(k)) != null) &&
(dir = compareComparables(kc, k, pk)) != 0)
p = (dir < 0) ? pl : pr;
else if ((q = pr.findTreeNode(h, k, kc)) != null)
return q;
else
p = pl;
} while (p != null);
}
return null;
}
}
/* ---------------- TreeBins -------------- */
/**
* TreeNodes used at the heads of bins. TreeBins do not hold user
* keys or values, but instead point to list of TreeNodes and
* their root. They also maintain a parasitic read-write lock
* forcing writers (who hold bin lock) to wait for readers (who do
* not) to complete before tree restructuring operations.
*/
static final class TreeBin extends Node {
TreeNode root;
volatile TreeNode first;
volatile Thread waiter;
volatile int lockState;
// values for lockState
static final int WRITER = 1; // set while holding write lock
static final int WAITER = 2; // set when waiting for write lock
static final int READER = 4; // increment value for setting read lock
/**
* Tie-breaking utility for ordering insertions when equal
* hashCodes and non-comparable. We don't require a total
* order, just a consistent insertion rule to maintain
* equivalence across rebalancings. Tie-breaking further than
* necessary simplifies testing a bit.
*/
static int tieBreakOrder(Object a, Object b) {
int d;
if (a == null || b == null ||
(d = a.getClass().getName().
compareTo(b.getClass().getName())) == 0)
d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
-1 : 1);
return d;
}
/**
* Creates bin with initial set of nodes headed by b.
*/
TreeBin(TreeNode b) {
super(TREEBIN, null, null, null);
this.first = b;
TreeNode r = null;
for (TreeNode x = b, next; x != null; x = next) {
next = (TreeNode)x.next;
x.left = x.right = null;
if (r == null) {
x.parent = null;
x.red = false;
r = x;
}
else {
K k = x.key;
int h = x.hash;
Class> kc = null;
for (TreeNode p = r;;) {
int dir, ph;
K pk = p.key;
if ((ph = p.hash) > h)
dir = -1;
else if (ph < h)
dir = 1;
else if ((kc == null &&
(kc = comparableClassFor(k)) == null) ||
(dir = compareComparables(kc, k, pk)) == 0)
dir = tieBreakOrder(k, pk);
TreeNode xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
x.parent = xp;
if (dir <= 0)
xp.left = x;
else
xp.right = x;
r = balanceInsertion(r, x);
break;
}
}
}
}
this.root = r;
assert checkInvariants(root);
}
/**
* Acquires write lock for tree restructuring.
*/
private final void lockRoot() {
if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
contendedLock(); // offload to separate method
}
/**
* Releases write lock for tree restructuring.
*/
private final void unlockRoot() {
lockState = 0;
}
/**
* Possibly blocks awaiting root lock.
*/
private final void contendedLock() {
boolean waiting = false;
for (int s;;) {
if (((s = lockState) & WRITER) == 0) {
if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
if (waiting)
waiter = null;
return;
}
}
else if ((s & WAITER) == 0) {
if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
waiting = true;
waiter = Thread.currentThread();
}
}
else if (waiting)
LockSupport.park(this);
}
}
/**
* Returns matching node or null if none. Tries to search
* using tree comparisons from root, but continues linear
* search when lock not available.
*/
final Node find(int h, Object k) {
if (k != null) {
for (Node e = first; e != null; e = e.next) {
int s; K ek;
if (((s = lockState) & (WAITER|WRITER)) != 0) {
if (e.hash == h &&
((ek = e.key) == k || (ek != null && k.equals(ek))))
return e;
}
else if (U.compareAndSwapInt(this, LOCKSTATE, s,
s + READER)) {
TreeNode r, p;
try {
p = ((r = root) == null ? null :
r.findTreeNode(h, k, null));
} finally {
Thread w;
int ls;
do {} while (!U.compareAndSwapInt
(this, LOCKSTATE,
ls = lockState, ls - READER));
if (ls == (READER|WAITER) && (w = waiter) != null)
LockSupport.unpark(w);
}
return p;
}
}
}
return null;
}
/**
* Finds or adds a node.
* @return null if added
*/
final TreeNode