V put(K key, int hash, V value, boolean onlyIfAbsent) {
lock();
try {
int c = count;
HashEntry[] tab = table;
int index = hash & (tab.length - 1);
HashEntry<K, V> first = (HashEntry<K, V>) tab[index];
for (HashEntry<K, V> e = first; e != null; e = (HashEntry<K, V>) e.next) {
if (e.hash == hash && key.equals(e.key)) {
V oldValue = e.value;
if (!onlyIfAbsent) e.value = value;
++modCount;
count = c; // write-volatile
return oldValue;
}
}
tab[index] = new HashEntry<K, V>(hash, key, value, first);
++modCount;
++c;
count = c; // write-volatile
if (c > threshold) setTable(rehash(tab));
return null;
} finally {
unlock();
}
}
boolean replace(K key, int hash, V oldValue, V newValue) {
lock();
try {
int c = count;
HashEntry[] tab = table;
int index = hash & (tab.length - 1);
HashEntry<K, V> first = (HashEntry<K, V>) tab[index];
HashEntry<K, V> e = first;
for (; ; ) {
if (e == null) return false;
if (e.hash == hash && key.equals(e.key)) break;
e = e.next;
}
V v = e.value;
if (v == null || !oldValue.equals(v)) return false;
e.value = newValue;
count = c; // write-volatile
return true;
} finally {
unlock();
}
}