Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / IteratingNestedCallback.java

diff --git a/lib/jetty/org/eclipse/jetty/util/IteratingNestedCallback.java b/lib/jetty/org/eclipse/jetty/util/IteratingNestedCallback.java
new file mode 100644 (file)
index 0000000..e018f43
--- /dev/null
+++ b/lib/jetty/org/eclipse/jetty/util/IteratingNestedCallback.java
@@ -0,0 +1,68 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+
+/* ------------------------------------------------------------ */
+/** Iterating Nested Callback.
+ * <p>This specialized callback is used when breaking up an
+ * asynchronous task into smaller asynchronous tasks.  A typical pattern
+ * is that a successful callback is used to schedule the next sub task, but 
+ * if that task completes quickly and uses the calling thread to callback
+ * the success notification, this can result in a growing stack depth.
+ * </p>
+ * <p>To avoid this issue, this callback uses an AtomicBoolean to note 
+ * if the success callback has been called during the processing of a 
+ * sub task, and if so then the processing iterates rather than recurses.
+ * </p>
+ * <p>This callback is passed to the asynchronous handling of each sub
+ * task and a call the {@link #succeeded()} on this call back represents
+ * completion of the subtask.  Only once all the subtasks are completed is 
+ * the {@link Callback#succeeded()} method called on the {@link Callback} instance
+ * passed the the {@link #IteratingNestedCallback(Callback)} constructor.</p>
+ *  
+ */
+public abstract class IteratingNestedCallback extends IteratingCallback
+{
+    final Callback _callback;
+    
+    public IteratingNestedCallback(Callback callback)
+    {
+        _callback=callback;
+    }
+    
+    @Override
+    protected void completed()
+    {
+        _callback.succeeded();
+    }
+
+    @Override
+    public void failed(Throwable x)
+    {
+        super.failed(x);
+        _callback.failed(x);
+    }
+
+    @Override
+    public String toString()
+    {
+        return String.format("%s@%x",getClass().getSimpleName(),hashCode());
+    }
+}