1 files changed, 105 insertions, 0 deletions
diff --git a/qpid/java/broker/src/main/java/org/apache/qpid/server/util/LoggingProxy.java b/qpid/java/broker/src/main/java/org/apache/qpid/server/util/LoggingProxy.java
new file mode 100644
index 0000000000..eda97e0ed2
--- /dev/null
+++ b/qpid/java/broker/src/main/java/org/apache/qpid/server/util/LoggingProxy.java
@@ -0,0 +1,105 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+package org.apache.qpid.server.util;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.Arrays;
+
+/**
+ * Dynamic proxy that records invocations in a fixed size circular buffer,
+ * dumping details on hitting an exception.
+ * <p>
+ * Useful in debugging.
+ * <p>
+ */
+public class LoggingProxy implements InvocationHandler
+{
+    private final Object _target;
+    private final CircularBuffer _log;
+
+    public LoggingProxy(Object target, int size)
+    {
+        _target = target;
+        _log = new CircularBuffer(size);
+    }
+
+    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
+    {
+        try
+        {
+            entered(method, args);
+            Object result = method.invoke(_target, args);
+            returned(method, result);
+            return result;
+        }
+        catch(InvocationTargetException e)
+        {
+            dump();
+            throw e.getTargetException();
+        }
+    }
+
+    void dump()
+    {
+        _log.dump();
+    }
+
+    CircularBuffer getBuffer()
+    {
+        return _log;
+    }
+
+    private synchronized void entered(Method method, Object[] args)
+    {
+        if (args == null)
+        {
+            _log.add(Thread.currentThread() + ": " + method.getName() + "() entered");
+        }
+        else
+        {
+            _log.add(Thread.currentThread() + ": " + method.getName() + "(" + Arrays.toString(args) + ") entered");
+        }
+    }
+
+    private synchronized void returned(Method method, Object result)
+    {
+        if (method.getReturnType() == Void.TYPE)
+        {
+            _log.add(Thread.currentThread() + ": " + method.getName() + "() returned");
+        }
+        else
+        {
+            _log.add(Thread.currentThread() + ": " + method.getName() + "() returned " + result);
+        }
+    }
+
+    public Object getProxy(Class... c)
+    {
+        return Proxy.newProxyInstance(_target.getClass().getClassLoader(), c, this);
+    }
+
+    public int getBufferSize() {
+        return _log.size();
+    }
+}