FileCleanerCleanup.java

/*
 * 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.t2framework.confeito.apache.commons.fileupload.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletContextEvent;

import org.t2framework.confeito.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();
	}
}