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.axiom.attachments.lifecycle.impl; import java.io.File; import java.io.IOException; import java.security.AccessController; import java.security.PrivilegedActionException; import java.security.PrivilegedExceptionAction; import java.util.Hashtable; import org.apache.axiom.attachments.lifecycle.LifecycleManager; import org.apache.axiom.util.UIDGenerator; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class LifecycleManagerImpl implements LifecycleManager { private static final Log log = LogFactory.getLog(LifecycleManagerImpl.class); //Hashtable to store file accessors. private static Hashtable table = new Hashtable(); private VMShutdownHook hook = null; public LifecycleManagerImpl() { super(); } /* (non-Javadoc) * @see org.apache.axiom.lifecycle.LifecycleManager#create(java.lang.String) */ public FileAccessor create(String attachmentDir) throws IOException { if (log.isDebugEnabled()) { log.debug("Start Create()"); } File file = null; File dir = null; if (attachmentDir != null) { dir = new File(attachmentDir); if (!dir.exists()) { dir.mkdirs(); } } if (!dir.isDirectory()) { throw new IllegalArgumentException( "Given Axis2 Attachment File Cache Location " + dir + " should be a directory."); } // Generate unique id. The UID generator is used so that we can limit // synchronization with the java random number generator. String id = UIDGenerator.generateUID(); String fileString = "Axis2" + id + ".att"; file = new File(dir, fileString); FileAccessor fa = new FileAccessor(this, file); //add the fileAccesor to table table.put(fileString, fa); //Default behaviour deleteOnExit(file); if (log.isDebugEnabled()) { log.debug("End Create()"); } return fa; } /* (non-Javadoc) * @see org.apache.axiom.lifecycle.LifecycleManager#delete(java.io.File) */ public void delete(File file) throws IOException { if (log.isDebugEnabled()) { log.debug("Start delete()"); } if (file != null && file.exists()) { table.remove(file); if (log.isDebugEnabled()) { log.debug("invoking file.delete()"); } if (file.delete()) { if (log.isDebugEnabled()) { log.debug("delete() successful"); } } else { if (log.isDebugEnabled()) { log.debug("Cannot delete file, set to delete on VM shutdown"); } deleteOnExit(file); } } if (log.isDebugEnabled()) { log.debug("End delete()"); } } /* (non-Javadoc) * @see org.apache.axiom.lifecycle.LifecycleManager#deleteOnExit(java.io.File) */ public void deleteOnExit(File file) throws IOException { if (log.isDebugEnabled()) { log.debug("Start deleteOnExit()"); } if (hook == null) { hook = RegisterVMShutdownHook(); } if (file != null) { if (log.isDebugEnabled()) { log.debug("Invoking deleteOnExit() for file = " + file.getAbsolutePath()); } hook.add(file); table.remove(file); } if (log.isDebugEnabled()) { log.debug("End deleteOnExit()"); } } /* (non-Javadoc) * @see org.apache.axiom.lifecycle.LifecycleManager#deleteOnTimeInterval(int) */ public void deleteOnTimeInterval(int interval, File file) throws IOException { if (log.isDebugEnabled()) { log.debug("Start deleteOnTimeInterval()"); } Thread t = new Thread(new LifecycleManagerImpl.FileDeletor(interval, file)); t.setDaemon(true); t.start(); if (log.isDebugEnabled()) { log.debug("End deleteOnTimeInterval()"); } } private VMShutdownHook RegisterVMShutdownHook() throws RuntimeException { if (log.isDebugEnabled()) { log.debug("Start RegisterVMShutdownHook()"); } try { hook = (VMShutdownHook) AccessController.doPrivileged(new PrivilegedExceptionAction() { public Object run() throws SecurityException, IllegalStateException, IllegalArgumentException { VMShutdownHook hook = VMShutdownHook.hook(); if (!hook.isRegistered()) { Runtime.getRuntime().addShutdownHook(hook); hook.setRegistered(true); } return hook; } }); } catch (PrivilegedActionException e) { if (log.isDebugEnabled()) { log.debug("Exception thrown from AccessController: " + e); log.debug("VM Shutdown Hook not registered."); } throw new RuntimeException(e); } if (log.isDebugEnabled()) { log.debug("Exit RegisterVMShutdownHook()"); } return hook; } public class FileDeletor implements Runnable { int interval; File _file; public FileDeletor(int interval, File file) { super(); this.interval = interval; this._file = file; } public void run() { try { Thread.sleep(interval * 1000); if (_file.exists()) { table.remove(_file); _file.delete(); } } catch (InterruptedException e) { //Log Exception if (log.isDebugEnabled()) { log.warn("InterruptedException occured " + e.getMessage()); } } } } public FileAccessor getFileAccessor(String fileName) throws IOException { return (FileAccessor) table.get(fileName); } }