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/*
* Copyright 2000-2014 JetBrains s.r.o.
*
* 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 com.intellij.util;
import com.intellij.openapi.Disposable;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.util.Disposer;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.EventListener;
import java.util.List;
/**
* @author max
*/
public class EventDispatcher<T extends EventListener> {
private static final Logger LOG = Logger.getInstance("#com.intellij.util.EventDispatcher");
private final T myMulticaster;
private final List<T> myListeners = ContainerUtil.createLockFreeCopyOnWriteList();
public static <T extends EventListener> EventDispatcher<T> create(@NotNull Class<T> listenerClass) {
return new EventDispatcher<T>(listenerClass);
}
private EventDispatcher(@NotNull Class<T> listenerClass) {
LOG.assertTrue(listenerClass.isInterface(), "listenerClass must be an interface");
InvocationHandler handler = new InvocationHandler() {
@Override
@NonNls
public Object invoke(Object proxy, final Method method, final Object[] args) throws Throwable {
if (method.getDeclaringClass().getName().equals("java.lang.Object")) {
@NonNls String methodName = method.getName();
if (methodName.equals("toString")) {
return "Multicaster";
}
else if (methodName.equals("hashCode")) {
return Integer.valueOf(System.identityHashCode(proxy));
}
else if (methodName.equals("equals")) {
return proxy == args[0] ? Boolean.TRUE : Boolean.FALSE;
}
else {
LOG.error("Incorrect Object's method invoked for proxy:" + methodName);
return null;
}
}
else {
dispatch(method, args);
return null;
}
}
};
//noinspection unchecked
myMulticaster = (T)Proxy.newProxyInstance(listenerClass.getClassLoader(), new Class[]{listenerClass}, handler);
}
@NotNull
public T getMulticaster() {
return myMulticaster;
}
private void dispatch(@NotNull Method method, Object[] args) {
method.setAccessible(true);
for (T listener : myListeners) {
try {
method.invoke(listener, args);
}
catch (AbstractMethodError ignored) {
// Do nothing. This listener just does not implement something newly added yet.
// AbstractMethodError is normally wrapped in InvocationTargetException,
// but some Java versions didn't do it in some cases (see http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6531596)
}
catch (RuntimeException e) {
throw e;
}
catch (Exception e) {
final Throwable cause = e.getCause();
if (cause instanceof RuntimeException) {
throw (RuntimeException)cause;
}
else if (!(cause instanceof AbstractMethodError)) { // AbstractMethodError means this listener doesn't implement some new method in interface
LOG.error(cause);
}
}
}
}
public void addListener(@NotNull T listener) {
myListeners.add(listener);
}
public void addListener(@NotNull final T listener, @NotNull Disposable parentDisposable) {
addListener(listener);
Disposer.register(parentDisposable, new Disposable() {
@Override
public void dispose() {
removeListener(listener);
}
});
}
public void removeListener(@NotNull T listener) {
myListeners.remove(listener);
}
public boolean hasListeners() {
return !myListeners.isEmpty();
}
@NotNull
public List<T> getListeners() {
return myListeners;
}
}
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