Java tutorial
/* * 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.commons.fileupload.servlet; import javax.servlet.ServletContext; import javax.servlet.ServletContextListener; import javax.servlet.ServletContextEvent; import org.apache.commons.io.FileCleaningTracker; /** * A servlet context listener, which ensures that the * {@link org.apache.commons.io.FileCleaner FileCleaner's} * reaper thread is terminated, * when the web application is destroyed. */ public class FileCleanerCleanup implements ServletContextListener { /** * Attribute name, which is used for storing an instance of * {@link FileCleaningTracker} in the web application. */ public static final String FILE_CLEANING_TRACKER_ATTRIBUTE = FileCleanerCleanup.class.getName() + ".FileCleaningTracker"; /** * Returns the instance of {@link FileCleaningTracker}, which is * associated with the given {@link ServletContext}. * @param pServletContext The servlet context to query * @return The contexts tracker */ public static FileCleaningTracker getFileCleaningTracker(ServletContext pServletContext) { return (FileCleaningTracker) pServletContext.getAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE); } /** * Sets the instance of {@link FileCleaningTracker}, which is * associated with the given {@link ServletContext}. * @param pServletContext The servlet context to modify * @param pTracker The tracker to set */ public static void setFileCleaningTracker(ServletContext pServletContext, FileCleaningTracker pTracker) { pServletContext.setAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE, pTracker); } /** * Called when the web application is initialized. Does * nothing. * @param sce The servlet context, used for calling * {@link #setFileCleaningTracker(ServletContext, FileCleaningTracker)}. */ public void contextInitialized(ServletContextEvent sce) { setFileCleaningTracker(sce.getServletContext(), new FileCleaningTracker()); } /** * Called when the web application is being destroyed. * Calls {@link FileCleaningTracker#exitWhenFinished()}. * @param sce The servlet context, used for calling * {@link #getFileCleaningTracker(ServletContext)}. */ public void contextDestroyed(ServletContextEvent sce) { getFileCleaningTracker(sce.getServletContext()).exitWhenFinished(); } }