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+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org.  If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+package com.sun.star.lib.util;
+
+import java.util.LinkedList;
+
+/**
+   Helper class to asynchronously execute finalize methods.
+
+   Current JVMs seem not to be robust against long-running finalize methods, in
+   that such long-running finalize methods may lead to OutOfMemoryErrors.  This
+   class mitigates the problem by asynchronously shifting the bodies of
+   potentially long-running finalize methods into an extra thread.  Classes that
+   make use of this in their finalize methods are the proxies used in the
+   intra-process JNI UNO bridge and the inter-process Java URP UNO bridge (where
+   in both cases finalizers lead to synchronous UNO release calls).
+
+   If JVMs are getting more mature and should no longer have problems with
+   long-running finalize mehtods, this class could be removed again.
+*/
+public final class AsynchronousFinalizer {
+    /**
+       Add a job to be executed asynchronously.
+
+       The run method of the given job is called exactly once.  If it terminates
+       abnormally by throwing any Throwable, that is ignored.
+
+       @param job represents the body of some finalize method; must not be null.
+    */
+    public static void add(Job job) {
+        synchronized (queue) {
+            boolean first = queue.isEmpty();
+            queue.add(job);
+            if (first) {
+                queue.notify();
+            }
+        }
+    }
+
+    /**
+       An interface to represent bodies of finalize methods.
+
+       Similar to Runnable, except that the run method may throw any Throwable
+       (which is effectively ignored by AsynchronousFinalizer.add, similar to
+       any Throwables raised by finalize being ignored).
+    */
+    public interface Job {
+        void run() throws Throwable;
+    }
+
+    private static final LinkedList queue = new LinkedList();
+
+    static {
+        Thread t = new Thread() {
+                public void run() {
+                    for (;;) {
+                        Job j;
+                        synchronized (queue) {
+                            while (queue.isEmpty()) {
+                                try {
+                                    queue.wait();
+                                } catch (InterruptedException e) {}
+                            }
+                            j = (Job) queue.remove(0);
+                        }
+                        try {
+                            j.run();
+                        } catch (Throwable e) {}
+                    }
+                }
+            };
+        t.setDaemon(true);
+        t.start();
+    }
+
+    private AsynchronousFinalizer() {}
+}