diff options
Diffstat (limited to 'jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/SynchronizedObject.java')
-rw-r--r-- | jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/SynchronizedObject.java | 372 |
1 files changed, 0 insertions, 372 deletions
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/SynchronizedObject.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/SynchronizedObject.java deleted file mode 100644 index bcf83dbfa9..0000000000 --- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/SynchronizedObject.java +++ /dev/null @@ -1,372 +0,0 @@ -/******************************************************************************* - * Copyright (c) 2007, 2008 Oracle. All rights reserved. - * This program and the accompanying materials are made available under the - * terms of the Eclipse Public License v1.0, which accompanies this distribution - * and is available at http://www.eclipse.org/legal/epl-v10.html. - * - * Contributors: - * Oracle - initial API and implementation - ******************************************************************************/ -package org.eclipse.jpt.utility.internal; - -import java.io.Serializable; -import org.eclipse.jpt.utility.Command; - -/** - * This class provides synchronized access to an object of type T. - * It also provides protocol for suspending a thread until the - * value is set to null or a non-null value, with optional time-outs. - */ -public class SynchronizedObject<T> - implements Cloneable, Serializable -{ - /** Backing value. */ - private T value; - - /** Object to synchronize on. */ - private final Object mutex; - - private static final long serialVersionUID = 1L; - - - // ********** constructors ********** - - /** - * Create a synchronized object with the specified initial value - * and mutex. - */ - public SynchronizedObject(T value, Object mutex) { - super(); - this.value = value; - this.mutex = mutex; - } - - /** - * Create a synchronized object with the specified initial value. - */ - public SynchronizedObject(T value) { - super(); - this.value = value; - this.mutex = this; - } - - /** - * Create a synchronized object with an initial value of null. - */ - public SynchronizedObject() { - this(null); - } - - - // ********** accessors ********** - - /** - * Return the current value. - */ - public T value() { - synchronized (this.mutex) { - return this.value; - } - } - - /** - * Return whether the current value is null. - */ - public boolean isNull() { - synchronized (this.mutex) { - return this.value == null; - } - } - - /** - * Return whether the current value is not null. - */ - public boolean isNotNull() { - synchronized (this.mutex) { - return this.value != null; - } - } - - /** - * Set the value. If the value changes, all waiting - * threads are notified. - */ - public void setValue(T value) { - synchronized (this.mutex) { - if (this.value != value) { - this.value = value; - this.mutex.notifyAll(); - } - } - } - - /** - * Set the value to null. If the value changes, all waiting - * threads are notified. - */ - public void setNull() { - synchronized (this.mutex) { - this.setValue(null); - } - } - - /** - * Return the object this object locks on while performing - * its operations. - */ - public Object mutex() { - return this.mutex; - } - - - // ********** indefinite waits ********** - - /** - * Suspend the current thread until the value changes - * to the specified value. If the value is already the - * specified value, return immediately. - */ - public void waitUntilValueIs(T v) throws InterruptedException { - synchronized (this.mutex) { - while (this.value != v) { - this.mutex.wait(); - } - } - } - - /** - * Suspend the current thread until the value changes - * to something other than the specified value. If the - * value is already NOT the specified value, return immediately. - */ - public void waitUntilValueIsNot(T v) throws InterruptedException { - synchronized (this.mutex) { - while (this.value == v) { - this.mutex.wait(); - } - } - } - - /** - * Suspend the current thread until the value changes to null. - * If the value is already null, return immediately. - */ - public void waitUntilNull() throws InterruptedException { - synchronized (this.mutex) { - this.waitUntilValueIs(null); - } - } - - /** - * Suspend the current thread until the value changes - * to something other than null. - * If the value is already NOT null, return immediately. - */ - public void waitUntilNotNull() throws InterruptedException { - synchronized (this.mutex) { - this.waitUntilValueIsNot(null); - } - } - - /** - * Suspend the current thread until the value changes to - * something other than the specified value, then change - * it back to the specified value and continue executing. - * If the value is already NOT the specified value, set - * the value immediately. - */ - public void waitToSetValue(T v) throws InterruptedException { - synchronized (this.mutex) { - this.waitUntilValueIsNot(v); - this.setValue(v); - } - } - - /** - * Suspend the current thread until the value changes to - * something other than null, then change it back to null - * and continue executing. If the value is already NOT null, - * set the value to null immediately. - */ - public void waitToSetNull() throws InterruptedException { - synchronized (this.mutex) { - this.waitUntilNotNull(); - this.setValue(null); - } - } - - - // ********** timed waits ********** - - /** - * Suspend the current thread until the value changes - * to the specified value or the specified time-out occurs. - * The time-out is specified in milliseconds. Return true if the specified - * value was achieved; return false if a time-out occurred. - * If the value is already the specified value, return true immediately. - */ - public boolean waitUntilValueIs(T v, long timeout) throws InterruptedException { - synchronized (this.mutex) { - if (timeout == 0L) { - this.waitUntilValueIs(v); // wait indefinitely until notified - return true; // if it ever comes back, the condition was met - } - - long stop = System.currentTimeMillis() + timeout; - long remaining = timeout; - while ((this.value != v) && (remaining > 0L)) { - this.mutex.wait(remaining); - remaining = stop - System.currentTimeMillis(); - } - return (this.value == v); - } - } - - /** - * Suspend the current thread until the value changes to something - * other than the specified value or the specified time-out occurs. - * The time-out is specified in milliseconds. Return true if the specified - * value was removed; return false if a time-out occurred. - * If the value is already NOT the specified value, return true immediately. - */ - public boolean waitUntilValueIsNot(T v, long timeout) throws InterruptedException { - synchronized (this.mutex) { - if (timeout == 0L) { - this.waitUntilValueIsNot(v); // wait indefinitely until notified - return true; // if it ever comes back, the condition was met - } - - long stop = System.currentTimeMillis() + timeout; - long remaining = timeout; - while ((this.value == v) && (remaining > 0L)) { - this.mutex.wait(remaining); - remaining = stop - System.currentTimeMillis(); - } - return (this.value != v); - } - } - - /** - * Suspend the current thread until the value changes - * to null or the specified time-out occurs. - * The time-out is specified in milliseconds. Return true if the specified - * value was achieved; return false if a time-out occurred. - * If the value is already null, return true immediately. - */ - public boolean waitUntilNull(long timeout) throws InterruptedException { - synchronized (this.mutex) { - return this.waitUntilValueIs(null, timeout); - } - } - - /** - * Suspend the current thread until the value changes - * to something other than null or the specified time-out occurs. - * The time-out is specified in milliseconds. Return true if the specified - * value was achieved; return false if a time-out occurred. - * If the value is already NOT null, return true immediately. - */ - public boolean waitUntilNotNull(long timeout) throws InterruptedException { - synchronized (this.mutex) { - return this.waitUntilValueIsNot(null, timeout); - } - } - - /** - * Suspend the current thread until the value changes to - * something other than the specified value, then change - * it back to the specified value and continue executing. - * If the value does not change to something other than the - * specified before the time-out, simply continue executing - * without changing the value. - * The time-out is specified in milliseconds. Return true if the value was - * set to true; return false if a time-out occurred. - * If the value is already something other than the specified value, set - * the value immediately and return true. - */ - public boolean waitToSetValue(T v, long timeout) throws InterruptedException { - synchronized (this.mutex) { - boolean success = this.waitUntilValueIsNot(v, timeout); - if (success) { - this.setValue(v); - } - return success; - } - } - - /** - * Suspend the current thread until the value changes to something - * other than null, then change it back to null and continue executing. - * If the value does not change to something other than null before - * the time-out, simply continue executing without changing the value. - * The time-out is specified in milliseconds. Return true if the value was - * set to false; return false if a time-out occurred. - * If the value is already something other than null, set - * the value to null immediately and return true. - */ - public boolean waitToSetNull(long timeout) throws InterruptedException { - synchronized (this.mutex) { - boolean success = this.waitUntilNotNull(timeout); - if (success) { - this.setValue(null); - } - return success; - } - } - - - // ********** synchronized behavior ********** - - /** - * If current thread is not interrupted, execute the specified command - * with the mutex locked. This is useful for initializing the value in another - * thread. - */ - public void execute(Command command) throws InterruptedException { - if (Thread.interrupted()) { - throw new InterruptedException(); - } - synchronized (this.mutex) { - command.execute(); - } - } - - - // ********** standard methods ********** - - @Override - public SynchronizedObject<T> clone() { - try { - synchronized (this.mutex) { - @SuppressWarnings("unchecked") - SynchronizedObject<T> clone = (SynchronizedObject<T>) super.clone(); - return clone; - } - } catch (CloneNotSupportedException ex) { - throw new InternalError(); - } - } - - @Override - public boolean equals(Object obj) { - if ( ! (obj instanceof SynchronizedObject)) { - return false; - } - Object v1 = this.value(); - Object v2 = ((SynchronizedObject<?>) obj).value(); - return (v1 == null) ? - (v2 == null) : v1.equals(v2); - } - - @Override - public int hashCode() { - Object v = this.value(); - return (v == null) ? 0 : v.hashCode(); - } - - @Override - public String toString() { - return String.valueOf(this.value()); - } - -} |