(no commit message)

[utils] / support / general / src / main / java / org / wamblee / general / SerializableProxyFactory.java

diff --git a/support/general/src/main/java/org/wamblee/general/SerializableProxyFactory.java b/support/general/src/main/java/org/wamblee/general/SerializableProxyFactory.java
new file mode 100644 (file)
index 0000000..34b7e3a
--- /dev/null
+++ b/support/general/src/main/java/org/wamblee/general/SerializableProxyFactory.java
@@ -0,0 +1,113 @@
+/*
+ * 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.lang.reflect.InvocationHandler;
+import java.lang.reflect.Proxy;
+
+/**
+ * <p>
+ * Serializable proxy factory that allows to create serializable proxies to
+ * objects that are themselves not serializable.
+ * </p>
+ * 
+ * <p>
+ * This class does not do any cleanup so it is recommended to only use this in
+ * test utilities.
+ * </p>
+ * 
+ * 
+ * @author Erik Brakkee
+ * 
+ * @param <T>
+ */
+public class SerializableProxyFactory<T> {
+
+    private T svc;
+    private Class clazz;
+    private T proxy;
+
+    /**
+     * Constructs the factory.
+     * 
+     * @param aClass
+     *            Interface class of the service to proxy.
+     */
+    public SerializableProxyFactory(Class<T> aClass) {
+        this(aClass, null);
+    }
+
+    /**
+     * Constructs the factory with a callback to create thread-specific objects
+     * automatically.
+     * 
+     * @param aClass
+     *            Interface class of the service to proxy.
+     * @param aCallback
+     *            Callback to create the object if it does not exist. When null,
+     *            then no initialization is done.
+     */
+    public SerializableProxyFactory(Class<T> aClass, T aSvc) {
+        if (!aClass.isInterface()) {
+            throw new IllegalArgumentException("Class " + aClass.getName() +
+                " is not an interface");
+        }
+        if (!aClass.isInstance(aSvc)) {
+            throw new IllegalArgumentException("Object " + aSvc +
+                " cannot be cast to " + aSvc.getClass());
+        }
+        svc = aSvc;
+        clazz = aClass;
+        proxy = createProxy();
+
+    }
+
+    /**
+     * Gets the underlying service.
+     * 
+     * @return Service.
+     */
+    public T get() {
+        return svc;
+    }
+
+    /**
+     * Gets the proxy that delegates to the thread-specific instance set by
+     * {@link #set(Object)}
+     * 
+     * @return Proxy.
+     */
+    public T getProxy() {
+        return proxy;
+    }
+
+    private T createProxy() {
+        InvocationHandler handler = new SerializableInvocationHandler(svc,
+            clazz);
+        Class proxyClass = Proxy.getProxyClass(clazz.getClassLoader(),
+            new Class[] { clazz });
+        T proxyObj;
+        try {
+            proxyObj = (T) proxyClass.getConstructor(
+                new Class[] { InvocationHandler.class }).newInstance(
+                new Object[] { handler });
+            return proxyObj;
+        } catch (Exception e) {
+            throw new RuntimeException("Could not create proxy for " +
+                clazz.getName(), e);
+        }
+    }
+}