/*
* 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.mina.statemachine;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import org.apache.mina.statemachine.context.SingletonStateContextLookup;
import org.apache.mina.statemachine.context.StateContext;
import org.apache.mina.statemachine.context.StateContextLookup;
import org.apache.mina.statemachine.event.DefaultEventFactory;
import org.apache.mina.statemachine.event.Event;
import org.apache.mina.statemachine.event.EventArgumentsInterceptor;
import org.apache.mina.statemachine.event.EventFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Used to create proxies which will forward all method calls on them to a
* {@link StateMachine}.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 600096 $, $Date: 2007-12-01 05:00:27 -0700 (Sat, 01 Dec 2007) $
*/
public class StateMachineProxyFactory {
private static final Logger log = LoggerFactory.getLogger(StateMachineProxyFactory.class);
private static final Object[] EMPTY_ARGUMENTS = new Object[0];
private StateMachineProxyFactory() {
}
@SuppressWarnings("unchecked")
public static <T> T create(Class<T> iface, StateMachine sm) {
return (T) create(new Class[] { iface }, sm);
}
@SuppressWarnings("unchecked")
public static <T> T create(Class<T> iface, StateMachine sm, StateContextLookup contextLookup) {
return (T) create(new Class[] { iface }, sm, contextLookup);
}
@SuppressWarnings("unchecked")
public static <T> T create(Class<T> iface, StateMachine sm, StateContextLookup contextLookup,
EventArgumentsInterceptor interceptor) {
return (T) create(new Class[] { iface }, sm, contextLookup, interceptor, new DefaultEventFactory());
}
@SuppressWarnings("unchecked")
public static <T> T create(Class<T> iface, StateMachine sm, StateContextLookup contextLookup,
EventArgumentsInterceptor interceptor, EventFactory eventFactory) {
return (T) create(new Class[] { iface }, sm, contextLookup, interceptor, eventFactory);
}
public static Object create(Class<?>[] ifaces, StateMachine sm) {
return create(ifaces, sm, new SingletonStateContextLookup());
}
public static Object create(Class<?>[] ifaces, StateMachine sm, StateContextLookup contextLookup) {
return create(ifaces, sm, contextLookup, null, new DefaultEventFactory());
}
public static Object create(Class<?>[] ifaces, StateMachine sm, StateContextLookup contextLookup,
EventArgumentsInterceptor interceptor, EventFactory eventFactory) {
ClassLoader cl = StateMachineProxyFactory.class.getClassLoader();
InvocationHandler handler = new MethodInvocationHandler(sm, contextLookup, interceptor, eventFactory);
return Proxy.newProxyInstance(cl, ifaces, handler);
}
private static class MethodInvocationHandler implements InvocationHandler {
private final StateMachine sm;
private final StateContextLookup contextLookup;
private final EventArgumentsInterceptor interceptor;
private final EventFactory eventFactory;
public MethodInvocationHandler(StateMachine sm, StateContextLookup contextLookup,
EventArgumentsInterceptor interceptor, EventFactory eventFactory) {
this.contextLookup = contextLookup;
this.sm = sm;
this.interceptor = interceptor;
this.eventFactory = eventFactory;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if ("hashCode".equals(method.getName()) && args == null) {
return new Integer(System.identityHashCode(proxy));
}
if ("equals".equals(method.getName()) && args.length == 1) {
return Boolean.valueOf(proxy == args[0]);
}
if ("toString".equals(method.getName()) && args == null) {
return proxy.getClass().getName() + "@"
+ Integer.toHexString(System.identityHashCode(proxy));
}
if (log.isDebugEnabled()) {
log.debug("Method invoked: " + method);
}
args = args == null ? EMPTY_ARGUMENTS : args;
if (interceptor != null) {
args = interceptor.modify(args);
}
StateContext context = contextLookup.lookup(args);
if (context == null) {
throw new IllegalStateException("Cannot determine state "
+ "context for method invocation: " + method);
}
Event event = eventFactory.create(context, method, args);
sm.handle(event);
return null;
}
}
}