diff options
Diffstat (limited to 'external/jsr166/java/util/concurrent/atomic/AtomicIntegerArray.java')
-rw-r--r-- | external/jsr166/java/util/concurrent/atomic/AtomicIntegerArray.java | 255 |
1 files changed, 0 insertions, 255 deletions
diff --git a/external/jsr166/java/util/concurrent/atomic/AtomicIntegerArray.java b/external/jsr166/java/util/concurrent/atomic/AtomicIntegerArray.java deleted file mode 100644 index 2ad754fda..000000000 --- a/external/jsr166/java/util/concurrent/atomic/AtomicIntegerArray.java +++ /dev/null @@ -1,255 +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 <tt>int</tt> array 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 - */ -public class AtomicIntegerArray implements java.io.Serializable { - private static final long serialVersionUID = 2862133569453604235L; - - // setup to use Unsafe.compareAndSwapInt for updates - private static final Unsafe unsafe = Unsafe.getUnsafe(); - private static final int base = unsafe.arrayBaseOffset(int[].class); - private static final int scale = unsafe.arrayIndexScale(int[].class); - private final int[] array; - - private long rawIndex(int i) { - if (i < 0 || i >= array.length) - throw new IndexOutOfBoundsException("index " + i); - return base + i * scale; - } - - /** - * Creates a new AtomicIntegerArray of given length. - * - * @param length the length of the array - */ - public AtomicIntegerArray(int length) { - array = new int[length]; - // must perform at least one volatile write to conform to JMM - if (length > 0) - unsafe.putIntVolatile(array, rawIndex(0), 0); - } - - /** - * Creates a new AtomicIntegerArray 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 AtomicIntegerArray(int[] array) { - if (array == null) - throw new NullPointerException(); - int length = array.length; - this.array = new int[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.putIntVolatile(this.array, rawIndex(last), array[last]); - } - } - - /** - * 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 int get(int i) { - return unsafe.getIntVolatile(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, int newValue) { - unsafe.putIntVolatile(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, int newValue) { - unsafe.putOrderedInt(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 int getAndSet(int i, int newValue) { - while (true) { - int 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, int expect, int update) { - return unsafe.compareAndSwapInt(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, int expect, int update) { - return compareAndSet(i, expect, update); - } - - /** - * Atomically increments by one the element at index <tt>i</tt>. - * - * @param i the index - * @return the previous value - */ - public final int getAndIncrement(int i) { - while (true) { - int current = get(i); - int next = current + 1; - if (compareAndSet(i, current, next)) - return current; - } - } - - /** - * Atomically decrements by one the element at index <tt>i</tt>. - * - * @param i the index - * @return the previous value - */ - public final int getAndDecrement(int i) { - while (true) { - int current = get(i); - int next = current - 1; - if (compareAndSet(i, current, next)) - return current; - } - } - - /** - * Atomically adds the given value to the element at index <tt>i</tt>. - * - * @param i the index - * @param delta the value to add - * @return the previous value - */ - public final int getAndAdd(int i, int delta) { - while (true) { - int current = get(i); - int next = current + delta; - if (compareAndSet(i, current, next)) - return current; - } - } - - /** - * Atomically increments by one the element at index <tt>i</tt>. - * - * @param i the index - * @return the updated value - */ - public final int incrementAndGet(int i) { - while (true) { - int current = get(i); - int next = current + 1; - if (compareAndSet(i, current, next)) - return next; - } - } - - /** - * Atomically decrements by one the element at index <tt>i</tt>. - * - * @param i the index - * @return the updated value - */ - public final int decrementAndGet(int i) { - while (true) { - int current = get(i); - int next = current - 1; - if (compareAndSet(i, current, next)) - return next; - } - } - - /** - * Atomically adds the given value to the element at index <tt>i</tt>. - * - * @param i the index - * @param delta the value to add - * @return the updated value - */ - public final int addAndGet(int i, int delta) { - while (true) { - int current = get(i); - int next = current + delta; - if (compareAndSet(i, current, next)) - return next; - } - } - - /** - * 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); - } - -} |