diff options
| author | Tom Tromey <tromey@redhat.com> | 2006-06-16 18:12:22 +0000 |
|---|---|---|
| committer | Tom Tromey <tromey@redhat.com> | 2006-06-16 18:12:22 +0000 |
| commit | 6e3cb55ff69ff06734603f5c7f5d45f069a52db0 (patch) | |
| tree | 0208d06669c5e74a875cff595e4b44ecad89fe1b /external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java | |
| parent | fb10a7fb852158d97502c3658e3112193f8dd05f (diff) | |
| download | classpath-6e3cb55ff69ff06734603f5c7f5d45f069a52db0.tar.gz | |
* external/jsr166: Removed files from cvs trunk.
Diffstat (limited to 'external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java')
| -rw-r--r-- | external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java | 163 |
1 files changed, 0 insertions, 163 deletions
diff --git a/external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java b/external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java deleted file mode 100644 index 91b601ed9..000000000 --- a/external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java +++ /dev/null @@ -1,163 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain - */ - -package java.util.concurrent.atomic; -import sun.misc.Unsafe; -import java.util.*; - -/** - * An array of object references in which elements may be updated - * atomically. See the {@link java.util.concurrent.atomic} package - * specification for description of the properties of atomic - * variables. - * @since 1.5 - * @author Doug Lea - * @param <E> The base class of elements held in this array - */ -public class AtomicReferenceArray<E> implements java.io.Serializable { - private static final long serialVersionUID = -6209656149925076980L; - - private static final Unsafe unsafe = Unsafe.getUnsafe(); - private static final int base = unsafe.arrayBaseOffset(Object[].class); - private static final int scale = unsafe.arrayIndexScale(Object[].class); - private final Object[] array; - - private long rawIndex(int i) { - if (i < 0 || i >= array.length) - throw new IndexOutOfBoundsException("index " + i); - return base + i * scale; - } - - /** - * Creates a new AtomicReferenceArray of given length. - * @param length the length of the array - */ - public AtomicReferenceArray(int length) { - array = new Object[length]; - // must perform at least one volatile write to conform to JMM - if (length > 0) - unsafe.putObjectVolatile(array, rawIndex(0), null); - } - - /** - * 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 - */ - public AtomicReferenceArray(E[] array) { - 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); - } - } - - /** - * Returns the length of the array. - * - * @return the length of the array - */ - public final int length() { - return array.length; - } - - /** - * Gets the current value at position <tt>i</tt>. - * - * @param i the index - * @return the current value - */ - public final E get(int i) { - return (E) unsafe.getObjectVolatile(array, rawIndex(i)); - } - - /** - * Sets the element at position <tt>i</tt> to the given value. - * - * @param i the index - * @param newValue the new value - */ - public final void set(int i, E newValue) { - unsafe.putObjectVolatile(array, rawIndex(i), newValue); - } - - /** - * Eventually sets the element at position <tt>i</tt> to the given value. - * - * @param i the index - * @param newValue the new value - * @since 1.6 - */ - public final void lazySet(int i, E newValue) { - unsafe.putOrderedObject(array, rawIndex(i), newValue); - } - - - /** - * Atomically sets the element at position <tt>i</tt> to the given - * value and returns the old value. - * - * @param i the index - * @param newValue the new value - * @return the previous value - */ - public final E getAndSet(int i, E newValue) { - while (true) { - E current = get(i); - if (compareAndSet(i, current, newValue)) - return current; - } - } - - /** - * Atomically sets the element at position <tt>i</tt> to the given - * updated value if the current value <tt>==</tt> 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. - */ - public final boolean compareAndSet(int i, E expect, E update) { - return unsafe.compareAndSwapObject(array, rawIndex(i), - expect, update); - } - - /** - * Atomically sets the element at position <tt>i</tt> to the given - * updated value if the current value <tt>==</tt> the expected value. - * May fail spuriously and does not provide ordering guarantees, - * so is only rarely an appropriate alternative to <tt>compareAndSet</tt>. - * - * @param i the index - * @param expect the expected value - * @param update the new value - * @return true if successful. - */ - public final boolean weakCompareAndSet(int i, E expect, E update) { - return compareAndSet(i, expect, update); - } - - /** - * Returns the String representation of the current values of array. - * @return the String representation of the current values of array. - */ - public String toString() { - if (array.length > 0) // force volatile read - get(0); - return Arrays.toString(array); - } - -} |
