File	Doc	Category	Size	Date	Package
AtomicLongArray.java	API Doc	Java SE 6 API	7551	Tue Jun 10 00:25:58 BST 2008	java.util.concurrent.atomic

AtomicLongArray

• java.lang.Object

Fields Summary
private static final long	serialVersionUID
private static final Unsafe	unsafe
private static final int	base
private static final int	scale
private final long[]	array

Constructors Summary
public AtomicLongArray(int length) Creates a new AtomicLongArray of given length. param length the length of the array array = new long[length]; // must perform at least one volatile write to conform to JMM if (length > 0) unsafe.putLongVolatile(array, rawIndex(0), 0);
public AtomicLongArray(long[] array) Creates a new AtomicLongArray with the same length as, and all elements copied from, the given array. param array the array to copy elements from throws NullPointerException if array is null if (array == null) throw new NullPointerException(); int length = array.length; this.array = new long[length]; if (length > 0) { int last = length-1; for (int i = 0; i < last; ++i) this.array[i] = array[i]; // Do the last write as volatile unsafe.putLongVolatile(this.array, rawIndex(last), array[last]); }

Methods Summary
public long	addAndGet(int i, long delta) Atomically adds the given value to the element at index {@code i}. param i the index param delta the value to add return the updated value while (true) { long current = get(i); long next = current + delta; if (compareAndSet(i, current, next)) return next; }
public final boolean	compareAndSet(int i, long expect, long update) Atomically sets the value to the given updated value if the current value {@code ==} the expected value. param i the index 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(array, rawIndex(i), expect, update);
public final long	decrementAndGet(int i) Atomically decrements by one the element at index {@code i}. param i the index return the updated value while (true) { long current = get(i); long next = current - 1; if (compareAndSet(i, current, next)) return next; }
public final long	get(int i) Gets the current value at position {@code i}. param i the index return the current value return unsafe.getLongVolatile(array, rawIndex(i));
public final long	getAndAdd(int i, long delta) Atomically adds the given value to the element at index {@code i}. param i the index param delta the value to add return the previous value while (true) { long current = get(i); long next = current + delta; if (compareAndSet(i, current, next)) return current; }
public final long	getAndDecrement(int i) Atomically decrements by one the element at index {@code i}. param i the index return the previous value while (true) { long current = get(i); long next = current - 1; if (compareAndSet(i, current, next)) return current; }
public final long	getAndIncrement(int i) Atomically increments by one the element at index {@code i}. param i the index return the previous value while (true) { long current = get(i); long next = current + 1; if (compareAndSet(i, current, next)) return current; }
public final long	getAndSet(int i, long newValue) Atomically sets the element at position {@code i} to the given value and returns the old value. param i the index param newValue the new value return the previous value while (true) { long current = get(i); if (compareAndSet(i, current, newValue)) return current; }
public final long	incrementAndGet(int i) Atomically increments by one the element at index {@code i}. param i the index return the updated value while (true) { long current = get(i); long next = current + 1; if (compareAndSet(i, current, next)) return next; }
public final void	lazySet(int i, long newValue) Eventually sets the element at position {@code i} to the given value. param i the index param newValue the new value since 1.6 unsafe.putOrderedLong(array, rawIndex(i), newValue);
public final int	length() Returns the length of the array. return the length of the array return array.length;
private long	rawIndex(int i) if (i < 0 || i >= array.length) throw new IndexOutOfBoundsException("index " + i); return base + i * scale;
public final void	set(int i, long newValue) Sets the element at position {@code i} to the given value. param i the index param newValue the new value unsafe.putLongVolatile(array, rawIndex(i), newValue);
public java.lang.String	toString() Returns the String representation of the current values of array. return the String representation of the current values of array. if (array.length > 0) // force volatile read get(0); return Arrays.toString(array);
public final boolean	weakCompareAndSet(int i, 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 i the index param expect the expected value param update the new value return true if successful. return compareAndSet(i, expect, update);