*/
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.lang.reflect.Proxy;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.UUID;
/**
* Thread-specific proxy is used to create implementations of interfaces that
*
* This class is mostly used by infrastructure code (utilities) and test tools.
*
+ * Care has been taken so that the invocation handler is serializable.
+ * However, it is only serializable within one virtual machine. It cannot be used in a distributed context
+ * where it can be sent to another JVM.
+ *
* @param T
* Interface to proxy.
* @author Erik Brakkee
*
*/
public class ThreadSpecificProxyFactory<T> {
+
- /**
- * 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<String,ThreadLocal> STORAGE =
- initializeThreadLocal();
-
- private static class ThreadSpecificInvocationHandler<T> implements InvocationHandler, Serializable {
-
- private String id;
- private Class clazz;
-
- public ThreadSpecificInvocationHandler(String aId, Class aClass) {
- id = aId;
- clazz = aClass;
- }
-
- @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() + "'";
- }
- try {
- return aMethod.invoke(actualSvc, aArgs);
- } catch (InvocationTargetException e) {
- throw e.getCause();
- }
- }
- }
-
private ThreadLocal<T> svc;
private Class clazz;
private T proxy;
svc = new ThreadLocal<T>();
clazz = aClass;
proxy = createProxy();
- }
-
- private static Map<String, ThreadLocal> initializeThreadLocal() {
- Map<String,ThreadLocal> map = new HashMap<String,ThreadLocal>();
- return map;
+
}
/**
}
private T createProxy() {
- String id = UUID.randomUUID().toString();
- STORAGE.put(id, svc);
- InvocationHandler handler = new ThreadSpecificInvocationHandler(id, clazz);
+ InvocationHandler handler = new ThreadSpecificInvocationHandler(svc, clazz);
Class proxyClass = Proxy.getProxyClass(clazz.getClassLoader(),
new Class[] { clazz });
T proxyObj;