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package jsr166y; |
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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import java.util.concurrent.atomic.AtomicReference; |
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import java.util.concurrent.locks.LockSupport; |
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import sun.misc.Unsafe; |
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import java.lang.reflect.*; |
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/** |
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* A reusable synchronization barrier, similar in functionality to a |
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* parties result in IllegalStateExceptions. However, you can and |
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* should create tiered phasers to accommodate arbitrarily large sets |
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* of participants. |
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* |
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* @since 1.7 |
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* @author Doug Lea |
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*/ |
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public class Phaser { |
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/* |
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private static final int phaseMask = 0x7fffffff; |
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private static int unarrivedOf(long s) { |
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return (int)(s & ushortMask); |
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return (int) (s & ushortMask); |
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} |
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private static int partiesOf(long s) { |
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return ((int)s) >>> 16; |
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return ((int) s) >>> 16; |
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} |
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private static int phaseOf(long s) { |
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return (int)(s >>> 32); |
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return (int) (s >>> 32); |
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} |
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private static int arrivedOf(long s) { |
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} |
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private static long stateFor(int phase, int parties, int unarrived) { |
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return ((((long)phase) << 32) | (((long)parties) << 16) | |
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(long)unarrived); |
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return ((((long) phase) << 32) | (((long) parties) << 16) | |
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(long) unarrived); |
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} |
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private static long trippedStateFor(int phase, int parties) { |
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long lp = (long)parties; |
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return (((long)phase) << 32) | (lp << 16) | lp; |
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long lp = (long) parties; |
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return (((long) phase) << 32) | (lp << 16) | lp; |
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} |
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/** |
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private final AtomicReference<QNode> oddQ = new AtomicReference<QNode>(); |
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private AtomicReference<QNode> queueFor(int phase) { |
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return (phase & 1) == 0? evenQ : oddQ; |
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return ((phase & 1) == 0) ? evenQ : oddQ; |
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} |
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/** |
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* root if necessary. |
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*/ |
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private long getReconciledState() { |
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return parent == null? state : reconcileState(); |
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return (parent == null) ? state : reconcileState(); |
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} |
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/** |
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if (par == null) { // directly trip |
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if (casState |
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(s, |
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trippedStateFor(onAdvance(phase, parties)? -1 : |
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trippedStateFor(onAdvance(phase, parties) ? -1 : |
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((phase + 1) & phaseMask), parties))) { |
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releaseWaiters(phase); |
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break; |
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if (unarrived == 0) { |
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if (casState |
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(s, |
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trippedStateFor(onAdvance(phase, parties)? -1 : |
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trippedStateFor(onAdvance(phase, parties) ? -1 : |
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((phase + 1) & phaseMask), parties))) { |
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releaseWaiters(phase); |
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break; |
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* @throws InterruptedException if thread interrupted while waiting |
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* @throws TimeoutException if timed out while waiting |
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*/ |
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public int awaitAdvanceInterruptibly(int phase, long timeout, TimeUnit unit) |
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public int awaitAdvanceInterruptibly(int phase, |
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long timeout, TimeUnit unit) |
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throws InterruptedException, TimeoutException { |
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if (phase < 0) |
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return phase; |
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} |
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/** |
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* Returns the parent of this phaser, or null if none. |
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* Returns the parent of this phaser, or {@code null} if none. |
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* |
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* @return the parent of this phaser, or null if none |
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* @return the parent of this phaser, or {@code null} if none |
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*/ |
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public Phaser getParent() { |
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return parent; |
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* Overridable method to perform an action upon phase advance, and |
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* to control termination. This method is invoked whenever the |
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* barrier is tripped (and thus all other waiting parties are |
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* dormant). If it returns true, then, rather than advance the |
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* phase number, this barrier will be set to a final termination |
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* state, and subsequent calls to {@code isTerminated} will |
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* return true. |
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* dormant). If it returns {@code true}, then, rather than advance |
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* the phase number, this barrier will be set to a final |
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* termination state, and subsequent calls to {@link #isTerminated} |
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* will return true. |
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* |
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* <p> The default version returns true when the number of |
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* <p> The default version returns {@code true} when the number of |
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* registered parties is zero. Normally, overrides that arrange |
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* termination for other reasons should also preserve this |
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* property. |
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return p; |
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} |
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// Temporary Unsafe mechanics for preliminary release |
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private static Unsafe getUnsafe() throws Throwable { |
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try { |
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return Unsafe.getUnsafe(); |
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} catch (SecurityException se) { |
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try { |
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return java.security.AccessController.doPrivileged |
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(new java.security.PrivilegedExceptionAction<Unsafe>() { |
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public Unsafe run() throws Exception { |
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return getUnsafePrivileged(); |
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}}); |
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} catch (java.security.PrivilegedActionException e) { |
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throw e.getCause(); |
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} |
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} |
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} |
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// Unsafe mechanics |
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private static Unsafe getUnsafePrivileged() |
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throws NoSuchFieldException, IllegalAccessException { |
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Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
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f.setAccessible(true); |
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return (Unsafe) f.get(null); |
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} |
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private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
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private static final long stateOffset = |
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objectFieldOffset("state", Phaser.class); |
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private static long fieldOffset(String fieldName) |
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throws NoSuchFieldException { |
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return _unsafe.objectFieldOffset |
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(Phaser.class.getDeclaredField(fieldName)); |
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private final boolean casState(long cmp, long val) { |
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return UNSAFE.compareAndSwapLong(this, stateOffset, cmp, val); |
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} |
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static final Unsafe _unsafe; |
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static final long stateOffset; |
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static { |
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private static long objectFieldOffset(String field, Class<?> klazz) { |
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try { |
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_unsafe = getUnsafe(); |
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stateOffset = fieldOffset("state"); |
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} catch (Throwable e) { |
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throw new RuntimeException("Could not initialize intrinsics", e); |
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return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
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} catch (NoSuchFieldException e) { |
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// Convert Exception to corresponding Error |
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NoSuchFieldError error = new NoSuchFieldError(field); |
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error.initCause(e); |
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throw error; |
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} |
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} |
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final boolean casState(long cmp, long val) { |
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return _unsafe.compareAndSwapLong(this, stateOffset, cmp, val); |
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/** |
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* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
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* Replace with a simple call to Unsafe.getUnsafe when integrating |
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* into a jdk. |
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* |
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* @return a sun.misc.Unsafe |
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*/ |
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private static sun.misc.Unsafe getUnsafe() { |
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try { |
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return sun.misc.Unsafe.getUnsafe(); |
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} catch (SecurityException se) { |
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try { |
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return java.security.AccessController.doPrivileged |
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(new java.security |
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.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
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public sun.misc.Unsafe run() throws Exception { |
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java.lang.reflect.Field f = sun.misc |
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.Unsafe.class.getDeclaredField("theUnsafe"); |
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f.setAccessible(true); |
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return (sun.misc.Unsafe) f.get(null); |
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}}); |
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} catch (java.security.PrivilegedActionException e) { |
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throw new RuntimeException("Could not initialize intrinsics", |
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e.getCause()); |
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} |
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} |
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} |
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} |
