scandirconfigmxbean.java

一个小公司要求给写的很简单的任务管理系统。

/*
 * ScanDirConfigMXBean.java
 *
 * Created on July 12, 2006, 7:43 PM
 *
 * @(#)ScanDirConfigMXBean.java	1.2 06/08/02
 *
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

package com.sun.jmx.examples.scandir;

import com.sun.jmx.examples.scandir.config.DirectoryScannerConfig;
import com.sun.jmx.examples.scandir.config.ScanManagerConfig;
import java.io.IOException;
import javax.management.InstanceNotFoundException;

/**
 * <p>The <code>ScanDirConfigMXBean</code> is in charge of the 
 * <i>scandir</i> application configuration.
 * </p>
 * <p>The <code>ScanDirConfigMXBean</code> is an MBean which is able to
 * load and save the <i>scandir</i> application configuration to and from an 
 * XML file.
 * </p>
 * <p>
 * It will let you also interactively modify that configuration, which you
 * can later save to the file, by calling {@link #save}, or discard, by
 * reloading the file without saving - see {@link #load}.
 * </p>
 * <p>
 * There can be as many <code>ScanDirConfigMXBean</code> registered
 * in the MBeanServer as you like, but only one of them will be identified as
 * the current configuration of the {@link ScanManagerMXBean}. 
 * You can switch to another configuration by calling {@link 
 * ScanManagerMXBean#setConfigurationMBean 
 * ScanManagerMXBean.setConfigurationMBean}.
 * </p>
 * <p>
 * Once the current configuration has been loaded (by calling {@link #load})
 * or modified (by calling one of {@link #addDirectoryScanner 
 * addDirectoryScanner}, {@link #removeDirectoryScanner removeDirectoryScanner} 
 * or {@link #setConfiguration setConfiguration}) it can be pushed
 * to the {@link ScanManagerMXBean} by calling {@link 
 * ScanManagerMXBean#applyConfiguration 
 * ScanManagerMXBean.applyConfiguration(true)} - 
 * <code>true</code> means that we apply the configuration from memory, 
 * without first reloading the file.
 * </p>
 *
 * @author Sun Microsystems, 2006 - All rights reserved.
 */
public interface ScanDirConfigMXBean {
    /**
     * This state tells whether the configuration reflected by the
     * {@link ScanDirConfigMXBean} was loaded in memory, saved to the 
     * configuration file, or modified since last saved.
     * Note that this state doesn't tell whether the configuration was
     * applied by the {@link ScanManagerMXBean}.
     **/
    public enum SaveState {
        /** 
         * Initial state: the {@link ScanDirConfigMXBean} is created, but
         * neither {@link #load} or  {@link #save} was yet called.
         **/
        CREATED, 
        
        /**
         * The configuration reflected by the {@link ScanDirConfigMXBean} has
         * been loaded, but not modified yet.
         **/
        LOADED, 
        
        /**
         * The configuration was modified. The modifications are held in memory.
         * Call {@link #save} to save them to the file, or {@link #load} to
         * reload the file and discard them.
         **/
        MODIFIED, 
        
        /**
         * The configuration was saved. 
         **/
        SAVED
    };
    
    /**
     * Loads the configuration from the {@link 
     * #getConfigFilename configuration file}.
     * <p>Any unsaved modification will be lost. The {@link #getSaveState state}
     * is switched to {@link SaveState#LOADED LOADED}.
     * </p>
     * <p>
     * This action has no effect on the {@link ScanManagerMXBean} until
     * {@link ScanManagerMXBean#getConfigurationMBean ScanManagerMXBean} 
     * points to this MBean and {@link ScanManagerMXBean#applyConfiguration 
     * ScanManagerMXBean.applyConfiguration} is called.
     * </p>
     * @see #getSaveState()
     * @throws IOException The configuration couldn't be loaded from the file,
     *                     e.g. because the file doesn't exist or isn't 
     *                     readable.
     * @throws IOException A connection problem occurred when accessing
     *                     the underlying resource.
     * @throws InstanceNotFoundException The underlying MBean is not
     *         registered in the MBeanServer.
     **/
    public void load()
        throws IOException, InstanceNotFoundException;
    
    /**
     * Saves the configuration to the {@link 
     * #getConfigFilename configuration file}.
     *
     * <p>If the configuration file doesn't exists, this method will
     *    attempt to create it. Otherwise, the existing file will
     *    be renamed by appending a '~' to its name, and a new file
     *    will be created, in which the configuration will be saved.
     * The {@link #getSaveState state}
     * is switched to {@link SaveState#SAVED SAVED}.
     * </p>
     * <p>
     * This action has no effect on the {@link ScanManagerMXBean}.
     * </p>
     * @see #getSaveState()
     * 
     * @throws IOException The configuration couldn't be saved to the file,
     *                     e.g. because the file couldn't be created.
     * @throws IOException A connection problem occurred when accessing
     *                     the underlying resource.
     * @throws InstanceNotFoundException The underlying MBean is not
     *         registered in the MBeanServer.
     **/
    public void save()
        throws IOException, InstanceNotFoundException;
    
    /**
     * Gets the name of the configuration file. 
     * <p>If the configuration file doesn't exists, {@link #load} will fail
     * and {@link #save} will attempt to create the file.
     * </p>
     * 
     * @return The configuration file name for this MBean.
     * @throws IOException A connection problem occurred when accessing
     *                     the underlying resource.
     * @throws InstanceNotFoundException The underlying MBean is not
     *         registered in the MBeanServer.