| /* |
| * Copyright 2000-2013 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 java.lang.ref.WeakReference; |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Proxy; |
| |
| public abstract class WeakListener<Src, Listener> implements InvocationHandler{ |
| private final WeakReference<Listener> myDelegate; |
| private Src mySource; |
| |
| protected WeakListener(Src source, Class<Listener> listenerInterface, Listener listenerImpl) { |
| mySource = source; |
| myDelegate = new WeakReference<Listener>(listenerImpl); |
| final ClassLoader classLoader = listenerImpl.getClass().getClassLoader(); |
| final Listener proxy = (Listener)Proxy.newProxyInstance(classLoader, new Class[]{listenerInterface}, this); |
| addListener(source, proxy); |
| } |
| |
| protected abstract void addListener(Src source, Listener listener); |
| |
| protected abstract void removeListener(Src source, Listener listener); |
| |
| @Override |
| public final Object invoke(Object proxy, Method method, Object[] params) throws Throwable { |
| final Listener listenerImplObject = myDelegate.get(); |
| if (listenerImplObject == null) { // already collected |
| removeListener(mySource, (Listener)proxy); |
| mySource = null; |
| return null; |
| } |
| return method.invoke(listenerImplObject, params); |
| } |
| } |