001// Copyright 2004, 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.hivemind.service; 016 017/** 018 * Service which acts as a dispatch hub for events about the lifecycle of the current thread. 019 * <p> 020 * Note: prior to release 1.1.1, the ThreadEventNotifier implementation would retain the listeners 021 * after {@link #fireThreadCleanup()}, which could allow certain threads to retain a reference to a 022 * listener, and thus that listener's class loader, even after the an application redeployment, 023 * resulting in a massive memory leak. Starting with release 1.1.1, all listeners are discarded by 024 * {@link #fireThreadCleanup()}. 025 * 026 * @author Howard Lewis Ship 027 */ 028public interface ThreadEventNotifier 029{ 030 /** 031 * Adds the listener. The notifier retains the listener until {@link #fireThreadCleanup()} is 032 * invoked, at which point is discarded. 033 */ 034 public void addThreadCleanupListener(ThreadCleanupListener listener); 035 036 /** 037 * Removes the listener, if it has been previously added. If the listener has been added 038 * multiple times, only one instance is removed. Note that this method is rarely used, because 039 * all listeners are automatically removed by {@link #fireThreadCleanup()}. 040 */ 041 public void removeThreadCleanupListener(ThreadCleanupListener listener); 042 043 /** 044 * Invokes {@link ThreadCleanupListener#threadDidCleanup()} on all listeners, and discards the 045 * list of listeners. 046 */ 047 public void fireThreadCleanup(); 048}