File	Doc	Category	Size	Date	Package
AtomicLong.java	API Doc	Java SE 6 API	6786	Tue Jun 10 00:25:58 BST 2008	java.util.concurrent.atomic

AtomicLong

• java.lang.Object
  • java.lang.Number

Fields Summary
private static final long	serialVersionUID
private static final Unsafe	unsafe
private static final long	valueOffset
static final boolean	VM_SUPPORTS_LONG_CAS Records whether the underlying JVM supports lockless CompareAndSet for longs. While the unsafe.CompareAndSetLong method works in either case, some constructions should be handled at Java level to avoid locking user-visible locks.
private volatile long	value

Constructors Summary
public AtomicLong(long initialValue) Creates a new AtomicLong with the given initial value. param initialValue the initial value value = initialValue;
public AtomicLong() Creates a new AtomicLong with initial value {@code 0}.

Methods Summary
private static native boolean	VMSupportsCS8() Returns whether underlying JVM supports lockless CompareAndSet for longs. Called only once and cached in VM_SUPPORTS_LONG_CAS.
public final long	addAndGet(long delta) Atomically adds the given value to the current value. param delta the value to add return the updated value for (;;) { long current = get(); long next = current + delta; if (compareAndSet(current, next)) return next; }
public final boolean	compareAndSet(long expect, long update) Atomically sets the value to the given updated value if the current value {@code ==} the expected value. param expect the expected value param update the new value return true if successful. False return indicates that the actual value was not equal to the expected value. return unsafe.compareAndSwapLong(this, valueOffset, expect, update);
public final long	decrementAndGet() Atomically decrements by one the current value. return the updated value for (;;) { long current = get(); long next = current - 1; if (compareAndSet(current, next)) return next; }
public double	doubleValue() return (double)get();
public float	floatValue() return (float)get();
public final long	get() Gets the current value. return the current value return value;
public final long	getAndAdd(long delta) Atomically adds the given value to the current value. param delta the value to add return the previous value while (true) { long current = get(); long next = current + delta; if (compareAndSet(current, next)) return current; }
public final long	getAndDecrement() Atomically decrements by one the current value. return the previous value while (true) { long current = get(); long next = current - 1; if (compareAndSet(current, next)) return current; }
public final long	getAndIncrement() Atomically increments by one the current value. return the previous value while (true) { long current = get(); long next = current + 1; if (compareAndSet(current, next)) return current; }
public final long	getAndSet(long newValue) Atomically sets to the given value and returns the old value. param newValue the new value return the previous value while (true) { long current = get(); if (compareAndSet(current, newValue)) return current; }
public final long	incrementAndGet() Atomically increments by one the current value. return the updated value for (;;) { long current = get(); long next = current + 1; if (compareAndSet(current, next)) return next; }
public int	intValue() return (int)get();
public final void	lazySet(long newValue) Eventually sets to the given value. param newValue the new value since 1.6 unsafe.putOrderedLong(this, valueOffset, newValue);
public long	longValue() return (long)get();
public final void	set(long newValue) Sets to the given value. param newValue the new value value = newValue;
public java.lang.String	toString() Returns the String representation of the current value. return the String representation of the current value. return Long.toString(get());
public final boolean	weakCompareAndSet(long expect, long update) Atomically sets the value to the given updated value if the current value {@code ==} the expected value. May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to {@code compareAndSet}. param expect the expected value param update the new value return true if successful. return unsafe.compareAndSwapLong(this, valueOffset, expect, update);