--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/EDU/oswego/cs/dl/util/concurrent/TimeoutSync.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,69 @@
+/*
+  File: TimeoutSync.java
+
+  Originally written by Doug Lea and released into the public domain.
+  This may be used for any purposes whatsoever without acknowledgment.
+  Thanks for the assistance and support of Sun Microsystems Labs,
+  and everyone contributing, testing, and using this code.
+
+  History:
+  Date       Who                What
+   1Aug1998  dl               Create public version
+*/
+
+package EDU.oswego.cs.dl.util.concurrent;
+
+/**
+ * A TimeoutSync is an adaptor class that transforms all
+ * calls to acquire to instead invoke attempt with a predetermined
+ * timeout value.
+ *<p>
+ * <b>Sample Usage</b>. A TimeoutSync can be used to obtain
+ * Timeouts for locks used in SyncCollections. For example:
+ * <pre>
+ * Mutex lock = new Mutex();
+ * TimeoutSync timedLock = new TimeoutSync(lock, 1000); // 1 sec timeouts
+ * Set set = new SyncSet(new HashSet(), timedlock);
+ * try {
+ *   set. add("hi");
+ * }
+ * // SyncSets translate timeouts and other lock failures 
+ * //   to unsupported operation exceptions, 
+ * catch (UnsupportedOperationException ex) {
+ *    System.out.println("Lock failure");
+ * }
+ * </pre>  
+ *
+ * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>]
+ * @see Sync
+**/
+
+
+public class TimeoutSync implements Sync {
+
+  protected final Sync sync_;     // the adapted sync
+  protected final long timeout_;  // timeout value
+
+  /** 
+   * Create a TimeoutSync using the given Sync object, and
+   * using the given timeout value for all calls to acquire.
+   **/
+
+  public TimeoutSync(Sync sync, long timeout) {
+    sync_ = sync;
+    timeout_ = timeout;
+  }
+
+  public void acquire() throws InterruptedException {
+    if (!sync_.attempt(timeout_)) throw new TimeoutException(timeout_);
+  }
+
+  public boolean attempt(long msecs) throws InterruptedException {
+    return sync_.attempt(msecs);
+  }
+
+  public void release() {
+    sync_.release();
+  }
+
+}