001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.fileupload.servlet;
018    
019    import javax.servlet.ServletContext;
020    import javax.servlet.ServletContextListener;
021    import javax.servlet.ServletContextEvent;
022    
023    import org.apache.commons.io.FileCleaningTracker;
024    
025    
026    /**
027     * A servlet context listener, which ensures that the
028     * {@link org.apache.commons.io.FileCleaner FileCleaner's}
029     * reaper thread is terminated,
030     * when the web application is destroyed.
031     */
032    public class FileCleanerCleanup implements ServletContextListener {
033        /**
034         * Attribute name, which is used for storing an instance of
035         * {@link FileCleaningTracker} in the web application.
036         */
037        public static final String FILE_CLEANING_TRACKER_ATTRIBUTE
038            = FileCleanerCleanup.class.getName() + ".FileCleaningTracker";
039    
040        /**
041         * Returns the instance of {@link FileCleaningTracker}, which is
042         * associated with the given {@link ServletContext}.
043         * @param pServletContext The servlet context to query
044         * @return The contexts tracker
045         */
046        public static FileCleaningTracker
047                getFileCleaningTracker(ServletContext pServletContext) {
048            return (FileCleaningTracker)
049                pServletContext.getAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE);
050        }
051    
052        /**
053         * Sets the instance of {@link FileCleaningTracker}, which is
054         * associated with the given {@link ServletContext}.
055         * @param pServletContext The servlet context to modify
056         * @param pTracker The tracker to set
057         */
058        public static void setFileCleaningTracker(ServletContext pServletContext,
059                FileCleaningTracker pTracker) {
060            pServletContext.setAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE, pTracker);
061        }
062    
063        /**
064         * Called when the web application is initialized. Does
065         * nothing.
066         * @param sce The servlet context, used for calling
067         *   {@link #setFileCleaningTracker(ServletContext, FileCleaningTracker)}.
068         */
069        public void contextInitialized(ServletContextEvent sce) {
070            setFileCleaningTracker(sce.getServletContext(),
071                    new FileCleaningTracker());
072        }
073    
074        /**
075         * Called when the web application is being destroyed.
076         * Calls {@link FileCleaningTracker#exitWhenFinished()}.
077         * @param sce The servlet context, used for calling
078         *     {@link #getFileCleaningTracker(ServletContext)}.
079         */
080        public void contextDestroyed(ServletContextEvent sce) {
081            getFileCleaningTracker(sce.getServletContext()).exitWhenFinished();
082        }
083    }