1 files changed, 57 insertions, 0 deletions
diff --git a/libjava/classpath/external/jsr166/java/util/concurrent/locks/AbstractOwnableSynchronizer.java b/libjava/classpath/external/jsr166/java/util/concurrent/locks/AbstractOwnableSynchronizer.java
new file mode 100644
index 000000000..f3780e5a6
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+++ b/libjava/classpath/external/jsr166/java/util/concurrent/locks/AbstractOwnableSynchronizer.java
@@ -0,0 +1,57 @@
+/*
+ * 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.locks;
+
+/**
+ * A synchronizer that may be exclusively owned by a thread.  This
+ * class provides a basis for creating locks and related synchronizers
+ * that may entail a notion of ownership.  The
+ * <tt>AbstractOwnableSynchronizer</tt> class itself does not manage or
+ * use this information. However, subclasses and tools may use
+ * appropriately maintained values to help control and monitor access
+ * and provide diagnostics.
+ *
+ * @since 1.6
+ * @author Doug Lea
+ */
+public abstract class AbstractOwnableSynchronizer
+    implements java.io.Serializable {
+
+    /** Use serial ID even though all fields transient. */
+    private static final long serialVersionUID = 3737899427754241961L;
+
+    /**
+     * Empty constructor for use by subclasses.
+     */
+    protected AbstractOwnableSynchronizer() { }
+
+    /**
+     * The current owner of exclusive mode synchronization.
+     */
+    private transient Thread exclusiveOwnerThread;
+
+    /**
+     * Sets the thread that currently owns exclusive access. A
+     * <tt>null</tt> argument indicates that no thread owns access.
+     * This method does not otherwise impose any synchronization or
+     * <tt>volatile</tt> field accesses.
+     */
+    protected final void setExclusiveOwnerThread(Thread t) {
+        exclusiveOwnerThread = t;
+    }
+
+    /**
+     * Returns the thread last set by
+     * <tt>setExclusiveOwnerThread</tt>, or <tt>null</tt> if never
+     * set.  This method does not otherwise impose any synchronization
+     * or <tt>volatile</tt> field accesses.
+     * @return the owner thread
+     */
+    protected final Thread getExclusiveOwnerThread() {
+        return exclusiveOwnerThread;
+    }
+}