File	Doc	Category	Size	Date	Package
AtomicReferenceArray.java	API Doc	Java SE 6 API	5217	Tue Jun 10 00:25:58 BST 2008	java.util.concurrent.atomic

AtomicReferenceArray

• 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 Object[]	array

Constructors Summary
public AtomicReferenceArray(int length) Creates a new AtomicReferenceArray of given length. param length the length of the array array = new Object[length]; // must perform at least one volatile write to conform to JMM if (length > 0) unsafe.putObjectVolatile(array, rawIndex(0), null);
public AtomicReferenceArray(E[] array) Creates a new AtomicReferenceArray 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 Object[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 E e = array[last]; unsafe.putObjectVolatile(this.array, rawIndex(last), e); }

Methods Summary
public final boolean	compareAndSet(int i, E expect, E update) Atomically sets the element at position {@code i} 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.compareAndSwapObject(array, rawIndex(i), expect, update);
public final E	get(int i) Gets the current value at position {@code i}. param i the index return the current value return (E) unsafe.getObjectVolatile(array, rawIndex(i));
public final E	getAndSet(int i, E 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) { E current = get(i); if (compareAndSet(i, current, newValue)) return current; }
public final void	lazySet(int i, E 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.putOrderedObject(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, E newValue) Sets the element at position {@code i} to the given value. param i the index param newValue the new value unsafe.putObjectVolatile(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, E expect, E update) Atomically sets the element at position {@code i} 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);