--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/text/LayoutQueue.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,121 @@
+/*
+ * Copyright 1999 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package javax.swing.text;
+
+import java.util.Vector;
+
+/**
+ * A queue of text layout tasks.
+ *
+ * @author  Timothy Prinzing
+ * @see     AsyncBoxView
+ * @since   1.3
+ */
+public class LayoutQueue {
+
+    Vector tasks;
+    Thread worker;
+
+    static LayoutQueue defaultQueue;
+
+    /**
+     * Construct a layout queue.
+     */
+    public LayoutQueue() {
+        tasks = new Vector();
+    }
+
+    /**
+     * Fetch the default layout queue.
+     */
+    public static LayoutQueue getDefaultQueue() {
+        if (defaultQueue == null) {
+            defaultQueue = new LayoutQueue();
+        }
+        return defaultQueue;
+    }
+
+    /**
+     * Set the default layout queue.
+     *
+     * @param q the new queue.
+     */
+    public static void setDefaultQueue(LayoutQueue q) {
+        defaultQueue = q;
+    }
+
+    /**
+     * Add a task that is not needed immediately because
+     * the results are not believed to be visible.
+     */
+    public synchronized void addTask(Runnable task) {
+        if (worker == null) {
+            worker = new LayoutThread();
+            worker.start();
+        }
+        tasks.addElement(task);
+        notifyAll();
+    }
+
+    /**
+     * Used by the worker thread to get a new task to execute
+     */
+    protected synchronized Runnable waitForWork() {
+        while (tasks.size() == 0) {
+            try {
+                wait();
+            } catch (InterruptedException ie) {
+                return null;
+            }
+        }
+        Runnable work = (Runnable) tasks.firstElement();
+        tasks.removeElementAt(0);
+        return work;
+    }
+
+    /**
+     * low priority thread to perform layout work forever
+     */
+    class LayoutThread extends Thread {
+
+        LayoutThread() {
+            super("text-layout");
+            setPriority(Thread.MIN_PRIORITY);
+        }
+
+        public void run() {
+            Runnable work;
+            do {
+                work = waitForWork();
+                if (work != null) {
+                    work.run();
+                }
+            } while (work != null);
+        }
+
+
+    }
+
+}