summaryrefslogtreecommitdiff
path: root/external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java
diff options
context:
space:
mode:
authorTom Tromey <tromey@redhat.com>2006-06-16 18:12:22 +0000
committerTom Tromey <tromey@redhat.com>2006-06-16 18:12:22 +0000
commit6e3cb55ff69ff06734603f5c7f5d45f069a52db0 (patch)
tree0208d06669c5e74a875cff595e4b44ecad89fe1b /external/jsr166/java/util/concurrent/atomic/AtomicReferenceArray.java
parentfb10a7fb852158d97502c3658e3112193f8dd05f (diff)
downloadclasspath-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.java163
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);
- }
-
-}