scandirconfig.java

一个小公司要求给写的很简单的任务管理系统。

        synchronized(this) {
            config = new XmlConfigUtils(filename).readFromFile();
            if (configname != null) config = config.copy(configname);
            else configname = config.getName();
        
            status=LOADED;
        }
        sendNotification(NOTIFICATION_LOADED);
    }
    
    // see ScanDirConfigMXBean
    public void save() throws IOException {
        if (filename == null)
            throw new UnsupportedOperationException("load");
        synchronized (this) {
            new XmlConfigUtils(filename).writeToFile(config);
            status = SAVED;
        }
        sendNotification(NOTIFICATION_SAVED);
    }
        
    // see ScanDirConfigMXBean
    public ScanManagerConfig getConfiguration() {
        synchronized (this) {
            return XmlConfigUtils.xmlClone(config);
        }
    }

   
    // sends a notification indicating the new save state.
    private void sendNotification(String type) {
        final Object source = (objectName==null)?this:objectName;
        final Notification n = new Notification(type,source,
                getNextSeqNumber(),
                "The configuration is "+
                type.substring(type.lastIndexOf('.')+1));
        sendNotification(n);
    }
    

    /**
     * Allows the MBean to perform any operations it needs before being
     * registered in the MBean server. If the name of the MBean is not
     * specified, the MBean can provide a name for its registration. If
     * any exception is raised, the MBean will not be registered in the
     * MBean server.
     * @param server The MBean server in which the MBean will be registered.
     * @param name The object name of the MBean. This name is null if the
     * name parameter to one of the createMBean or registerMBean methods in
     * the MBeanServer interface is null. In that case, this method will
     * try to guess its MBean name by examining its configuration data.
     * If its configuration data is null (nothing was provided in the 
     * constructor) or doesn't contain a name, this method returns {@code null},
     * and registration will fail.
     * <p> 
     * Otherwise, if {@code name} wasn't {@code null} or if a default name could
     * be constructed, the name of the configuration will be set to
     * the value of the ObjectName's {@code name=} key, and the configuration 
     * data will always be renamed to reflect this change.
     * </p>
     * 
     * @return The name under which the MBean is to be registered. 
     * @throws Exception This exception will be caught by the MBean server and
     * re-thrown as an MBeanRegistrationException.
     */
    public ObjectName preRegister(MBeanServer server, ObjectName name) 
        throws Exception {
        if (name == null) {
            if (config == null) return null;
            if (config.getName() == null) return null;
            name = ScanManager.
                    makeMBeanName(ScanDirConfigMXBean.class,config.getName());
        }
        objectName = name;
        mbeanServer = server;
        synchronized (this) {
            configname = name.getKeyProperty("name");
            if (config == null) config = new ScanManagerConfig(configname);
            else config = config.copy(configname);
        }
        return name;
    }

    /**
     * Allows the MBean to perform any operations needed after having
     * been registered in the MBean server or after the registration has
     * failed.
     * <p>This implementation does nothing</p>
     * @param registrationDone Indicates whether or not the MBean has been
     * successfully registered in the MBean server. The value false means
     * that the registration has failed.
     */
    public void postRegister(Boolean registrationDone) {
        // Nothing to do here.
    }

    /**
     * Allows the MBean to perform any operations it needs before being
     * unregistered by the MBean server.
     * <p>This implementation does nothing</p>
     * @throws Exception This exception will be caught by the MBean server and
     * re-thrown as an MBeanRegistrationException.
     */
    public void preDeregister() throws Exception {
        // Nothing to do here.
    }

    /**
     * Allows the MBean to perform any operations needed after having been
     * unregistered in the MBean server.
     * <p>This implementation does nothing</p>
     */
    public void postDeregister() {
        // Nothing to do here.
    }

    // see ScanDirConfigMXBean
    public String getConfigFilename() {
        return filename;
    }

    // see ScanDirConfigMXBean
    public void setConfiguration(ScanManagerConfig config) {
        synchronized (this) {
            if (config == null) {
                this.config = null; 
                return;
            }
        
            if (configname == null) 
                configname = config.getName();
        
            this.config = config.copy(configname);
            status = MODIFIED;
        }
        sendNotification(NOTIFICATION_MODIFIED);
    }
    
    // see ScanDirConfigMXBean
    public DirectoryScannerConfig 
            addDirectoryScanner(String name, String dir, String filePattern, 
                                long sizeExceedsMaxBytes, long sinceLastModified) {
         final DirectoryScannerConfig scanner = 
                 new DirectoryScannerConfig(name);
         scanner.setRootDirectory(dir);
         if (filePattern!=null||sizeExceedsMaxBytes>0||sinceLastModified>0) {
            final FileMatch filter = new FileMatch();
            filter.setFilePattern(filePattern);
            filter.setSizeExceedsMaxBytes(sizeExceedsMaxBytes);
            if (sinceLastModified > 0)
                filter.setLastModifiedBefore(new Date(new Date().getTime()
                                                -sinceLastModified));
            scanner.addIncludeFiles(filter);
         }
         synchronized (this) {
            config.putScan(scanner);
            status = MODIFIED;
         }
         LOG.fine("config: "+config);
         sendNotification(NOTIFICATION_MODIFIED);
         return scanner;
    }

    // see ScanDirConfigMXBean
    public DirectoryScannerConfig removeDirectoryScanner(String name) 
        throws IOException, InstanceNotFoundException {
        final DirectoryScannerConfig scanner;
        synchronized (this) {
            scanner = config.removeScan(name);
            if (scanner == null)
                throw new IllegalArgumentException(name+": scanner not found");
            status = MODIFIED;
        }
        sendNotification(NOTIFICATION_MODIFIED);
        return scanner;
    }

    // see ScanDirConfigMXBean
    public SaveState getSaveState() {
        return status;
    }
    
    // These methods are used by ScanManager to guess a configuration name from
    // a configuration filename.
    //
    static String DEFAULT = "DEFAULT";
    
    private static String getBasename(String name) {
        final int dot = name.indexOf('.');
        if (dot<0)  return name;
        if (dot==0) return getBasename(name.substring(1));
        return name.substring(0,dot);
    }
    
    static String guessConfigName(String configFileName,String defaultFile) {
        try {
            if (configFileName == null) return DEFAULT;
            final File f = new File(configFileName);
            if (f.canRead()) {
                final String confname = XmlConfigUtils.read(f).getName();
                if (confname != null && confname.length()>0) return confname;
            }
            final File f2 = new File(defaultFile);
            if (f.equals(f2)) return DEFAULT;
            final String guess = getBasename(f.getName());
            if (guess == null) return DEFAULT;
            if (guess.length()==0) return DEFAULT;
            return guess;
        } catch (Exception x) {
            return DEFAULT;
        }
    }
    
    // Set by preRegister()
    private volatile MBeanServer mbeanServer;
    private volatile ObjectName objectName;
    
}