+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * Licensed 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.wamblee.general;
+
+import java.io.Serializable;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Invocation handler for thread-specific proxies.
+ *
+ * @author Erik Brakkee
+ *
+ * @param <T>
+ */
+class ThreadSpecificInvocationHandler<T> implements InvocationHandler, Serializable {
+
+ /**
+ * We store a map of unique ids of invocation handlers to thread local storage of the
+ * service. In this way, serialiability of the generated proxy is obtained (required by
+ * framweorks such as wicket). Also, different factories will still be separate and never
+ * use the same threadlocal storage.
+ */
+ private static Map<Integer,ThreadLocal> STORAGE = initializeThreadLocal();
+
+ private static AtomicInteger COUNTER = new AtomicInteger();
+
+ private static Map<Integer, ThreadLocal> initializeThreadLocal() {
+ Map<Integer,ThreadLocal> map = new ConcurrentHashMap<Integer,ThreadLocal>();
+ return map;
+ }
+
+
+ private int id;
+ private Class clazz;
+
+ /**
+ * Constructs the handler.
+ * @param aSvc Thread local for the service.
+ * @param aClass Service interface class.
+ */
+ public ThreadSpecificInvocationHandler(ThreadLocal aSvc, Class aClass) {
+ id = COUNTER.incrementAndGet();
+ clazz = aClass;
+ STORAGE.put(id, aSvc);
+ }
+
+ @Override
+ public Object invoke(Object aProxy, Method aMethod, Object[] aArgs)
+ throws Throwable {
+
+ ThreadLocal<T> local = STORAGE.get(id);
+ T actualSvc = local.get();
+ if ( aMethod.getName().equals("toString") && actualSvc == null) {
+ return "Thread-specific proxy for '" + clazz.getName() + "' id = " + id;
+ }
+ try {
+ return aMethod.invoke(actualSvc, aArgs);
+ } catch (InvocationTargetException e) {
+ throw e.getCause();
+ }
+ }
+}
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