org.jboss.forge.addon.resource.monitor.FileMonitor.java Source code

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Here is the source code for org.jboss.forge.addon.resource.monitor.FileMonitor.java

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/**
 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Eclipse Public License version 1.0, available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package org.jboss.forge.addon.resource.monitor;

import java.io.File;
import java.util.concurrent.ThreadFactory;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.enterprise.event.Observes;
import javax.inject.Singleton;

import org.apache.commons.io.filefilter.FileFilterUtils;
import org.apache.commons.io.filefilter.IOFileFilter;
import org.apache.commons.io.monitor.FileAlterationListener;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationObserver;
import org.jboss.forge.addon.resource.DirectoryResource;
import org.jboss.forge.addon.resource.FileResource;
import org.jboss.forge.addon.resource.ResourceFactory;
import org.jboss.forge.addon.resource.ResourceFilter;
import org.jboss.forge.furnace.container.cdi.events.Local;
import org.jboss.forge.furnace.event.PostStartup;
import org.jboss.forge.furnace.event.PreShutdown;

/**
 * This {@link FileMonitor} uses commons-io to listen for changes in files
 * 
 * @author <a href="ggastald@redhat.com">George Gastaldi</a>
 */
@Singleton
public class FileMonitor {
    private static final long CHECK_INTERVAL = Long.getLong("resource.monitor.interval", 5000L);

    private final Logger log = Logger.getLogger(getClass().getName());
    private FileAlterationMonitor alterationMonitor;

    public FileMonitor() {
        alterationMonitor = new FileAlterationMonitor(CHECK_INTERVAL);
        alterationMonitor.setThreadFactory(new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread resourceMonitorThread = new Thread(r, "Resource File Monitor");
                resourceMonitorThread.setDaemon(true);
                resourceMonitorThread.setContextClassLoader(null);
                return resourceMonitorThread;
            }
        });
    }

    void init(@Observes @Local PostStartup postStartup) throws Exception {
        alterationMonitor.start();
    }

    void destroy(@Observes @Local PreShutdown preShutdown) throws Exception {
        for (FileAlterationObserver observer : alterationMonitor.getObservers()) {
            for (FileAlterationListener listener : observer.getListeners()) {
                observer.removeListener(listener);
            }
            alterationMonitor.removeObserver(observer);
        }
        alterationMonitor.stop();
    }

    public ResourceMonitor registerMonitor(final ResourceFactory resourceFactory, final FileResource<?> resource,
            final ResourceFilter resourceFilter) {
        final DirectoryResource dirResource;
        IOFileFilter filter;
        if (resource instanceof DirectoryResource) {
            dirResource = (DirectoryResource) resource;
            filter = null;
        } else {
            dirResource = resource.getParent();
            filter = FileFilterUtils.nameFileFilter(resource.getName());
        }
        if (resourceFilter != null) {
            FileFilterResourceAdapter adapter = new FileFilterResourceAdapter(resourceFactory, resourceFilter);
            if (filter == null) {
                filter = adapter;
            } else {
                filter = FileFilterUtils.and(filter, adapter);
            }
        }
        File directory = dirResource.getUnderlyingResourceObject();
        FileAlterationObserver observer = new FileAlterationObserver(directory, filter);
        try {
            observer.initialize();
        } catch (Exception e) {
            log.log(Level.SEVERE, "Error while initializing File observer", e);
        }
        alterationMonitor.addObserver(observer);
        return new ResourceMonitorImpl(dirResource, resourceFactory, alterationMonitor, observer);
    }
}