bundles/org.eclipse.equinox.app/src/org/eclipse/equinox/internal/app/AppPersistence.java - equinox/rt.equinox.bundles - Git at Google

 /*******************************************************************************
  * Copyright (c) 2005, 2009 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.equinox.internal.app;

 import java.io.*;
 import java.util.*;
 import org.eclipse.osgi.framework.log.FrameworkLogEntry;
 import org.eclipse.osgi.service.datalocation.Location;
 import org.eclipse.osgi.storagemanager.StorageManager;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.*;
 import org.osgi.service.application.*;
 import org.osgi.service.event.Event;
 import org.osgi.service.event.EventConstants;
 import org.osgi.util.tracker.ServiceTracker;
 import org.osgi.util.tracker.ServiceTrackerCustomizer;

 /**
  * Manages all persistent data for ApplicationDescriptors (lock status,
  * scheduled applications etc.)
  */
 public class AppPersistence implements ServiceTrackerCustomizer {
 	private static final String PROP_CONFIG_AREA = "osgi.configuration.area"; //$NON-NLS-1$

 	private static final String FILTER_PREFIX = "(&(objectClass=org.eclipse.osgi.service.datalocation.Location)(type="; //$NON-NLS-1$
 	private static final String FILE_APPLOCKS = ".locks"; //$NON-NLS-1$
 	private static final String FILE_APPSCHEDULED = ".scheduled"; //$NON-NLS-1$
 	private static final String EVENT_HANDLER = "org.osgi.service.event.EventHandler"; //$NON-NLS-1$

 	private static final int DATA_VERSION = 2;
 	private static final byte NULL = 0;
 	private static final int OBJECT = 1;

 	private static BundleContext context;
 	private static ServiceTracker configTracker;
 	private static Location configLocation;
 	private static Collection locks = new ArrayList();
 	private static Map scheduledApps = new HashMap();
 	static ArrayList timerApps = new ArrayList();
 	private static StorageManager storageManager;
 	private static boolean scheduling = false;
 	static boolean shutdown = false;
 	private static int nextScheduledID = 1;
 	private static Thread timerThread;

 	static void start(BundleContext bc) {
 		context = bc;
 		shutdown = false;
 		initConfiguration();
 	}

 	static void stop() {
 		shutdown = true;
 		stopTimer();
 		if (storageManager != null) {
 			storageManager.close();
 			storageManager = null;
 		}
 		closeConfiguration();
 		context = null;
 	}

 	private static void initConfiguration() {
 		closeConfiguration(); // just incase
 		Filter filter = null;
 		try {
 			filter = context.createFilter(FILTER_PREFIX + PROP_CONFIG_AREA + "))"); //$NON-NLS-1$
 		} catch (InvalidSyntaxException e) {
 			// ignore this.  It should never happen as we have tested the above format.
 		}
 		configTracker = new ServiceTracker(context, filter, new AppPersistence());
 		configTracker.open();
 	}

 	private static void closeConfiguration() {
 		if (configTracker != null)
 			configTracker.close();
 		configTracker = null;
 	}

 	/**
 	 * Used by {@link ApplicationDescriptor} to determine if an application is locked.
 	 * @param desc the application descriptor
 	 * @return true if the application is persistently locked.
 	 */
 	public static boolean isLocked(ApplicationDescriptor desc) {
 		synchronized (locks) {
 			return locks.contains(desc.getApplicationId());
 		}
 	}

 	/**
 	 * Used by {@link ApplicationDescriptor} to determine lock and unlock and application.
 	 * @param desc the application descriptor
 	 * @param locked the locked flag
 	 */
 	public static void saveLock(ApplicationDescriptor desc, boolean locked) {
 		synchronized (locks) {
 			if (locked) {
 				if (!locks.contains(desc.getApplicationId())) {
 					locks.add(desc.getApplicationId());
 					saveData(FILE_APPLOCKS);
 				}
 			} else if (locks.remove(desc.getApplicationId())) {
 				saveData(FILE_APPLOCKS);
 			}
 		}
 	}

 	static void removeScheduledApp(EclipseScheduledApplication scheduledApp) {
 		boolean removed;
 		synchronized (scheduledApps) {
 			removed = scheduledApps.remove(scheduledApp.getScheduleId()) != null;
 			if (removed) {
 				saveData(FILE_APPSCHEDULED);
 			}
 		}
 		if (removed)
 			synchronized (timerApps) {
 				timerApps.remove(scheduledApp);
 			}
 	}

 	/**
 	 * Used by {@link ScheduledApplication} to persistently schedule an application launch
 	 * @param descriptor
 	 * @param arguments
 	 * @param topic
 	 * @param eventFilter
 	 * @param recurring
 	 * @return the scheduled application
 	 * @throws InvalidSyntaxException
 	 * @throws ApplicationException
 	 */
 	public static ScheduledApplication addScheduledApp(ApplicationDescriptor descriptor, String scheduleId, Map arguments, String topic, String eventFilter, boolean recurring) throws InvalidSyntaxException, ApplicationException {
 		if (!scheduling && !checkSchedulingSupport())
 			throw new ApplicationException(ApplicationException.APPLICATION_SCHEDULING_FAILED, "Cannot support scheduling without org.osgi.service.event package"); //$NON-NLS-1$
 		// check the event filter for correct syntax
 		context.createFilter(eventFilter);
 		EclipseScheduledApplication result;
 		synchronized (scheduledApps) {
 			result = new EclipseScheduledApplication(context, getNextScheduledID(scheduleId), descriptor.getApplicationId(), arguments, topic, eventFilter, recurring);
 			addScheduledApp(result);
 			saveData(FILE_APPSCHEDULED);
 		}
 		return result;
 	}

 	// must call this method while holding the scheduledApps lock
 	private static void addScheduledApp(EclipseScheduledApplication scheduledApp) {
 		if (ScheduledApplication.TIMER_TOPIC.equals(scheduledApp.getTopic())) {
 			synchronized (timerApps) {
 				timerApps.add(scheduledApp);
 				if (timerThread == null)
 					startTimer();
 			}
 		}
 		scheduledApps.put(scheduledApp.getScheduleId(), scheduledApp);
 		Hashtable serviceProps = new Hashtable();
 		if (scheduledApp.getTopic() != null)
 			serviceProps.put(EventConstants.EVENT_TOPIC, new String[] {scheduledApp.getTopic()});
 		if (scheduledApp.getEventFilter() != null)
 			serviceProps.put(EventConstants.EVENT_FILTER, scheduledApp.getEventFilter());
 		serviceProps.put(ScheduledApplication.SCHEDULE_ID, scheduledApp.getScheduleId());
 		serviceProps.put(ScheduledApplication.APPLICATION_PID, scheduledApp.getAppPid());
 		ServiceRegistration sr = context.registerService(new String[] {ScheduledApplication.class.getName(), EVENT_HANDLER}, scheduledApp, serviceProps);
 		scheduledApp.setServiceRegistration(sr);
 	}

 	private static String getNextScheduledID(String scheduledId) throws ApplicationException {
 		if (scheduledId != null) {
 			if (scheduledApps.get(scheduledId) != null)
 				throw new ApplicationException(ApplicationException.APPLICATION_DUPLICATE_SCHEDULE_ID, "Duplicate scheduled ID: " + scheduledId); //$NON-NLS-1$
 			return scheduledId;
 		}
 		if (nextScheduledID == Integer.MAX_VALUE)
 			nextScheduledID = 0;
 		String result = new Integer(nextScheduledID++).toString();
 		while (scheduledApps.get(result) != null && nextScheduledID < Integer.MAX_VALUE)
 			result = new Integer(nextScheduledID++).toString();
 		if (nextScheduledID == Integer.MAX_VALUE)
 			throw new ApplicationException(ApplicationException.APPLICATION_DUPLICATE_SCHEDULE_ID, "Maximum number of scheduled applications reached"); //$NON-NLS-1$
 		return result;
 	}

 	private static boolean checkSchedulingSupport() {
 		// cannot support scheduling without the event admin package
 		try {
 			Class.forName(EVENT_HANDLER);
 			scheduling = true;
 			return true;
 		} catch (ClassNotFoundException e) {
 			scheduling = false;
 			return false;
 		}
 	}

 	private synchronized static boolean loadData(String fileName) {
 		try {
 			Location location = configLocation;
 			if (location == null)
 				return false;
 			File theStorageDir = new File(location.getURL().getPath() + '/' + Activator.PI_APP);
 			if (storageManager == null) {
 				boolean readOnly = location.isReadOnly();
 				storageManager = new StorageManager(theStorageDir, readOnly ? "none" : null, readOnly); //$NON-NLS-1$
 				storageManager.open(!readOnly);
 			}
 			File dataFile = storageManager.lookup(fileName, false);
 			if (dataFile == null || !dataFile.isFile()) {
 				Location parent = location.getParentLocation();
 				if (parent != null) {
 					theStorageDir = new File(parent.getURL().getPath() + '/' + Activator.PI_APP);
 					StorageManager tmp = new StorageManager(theStorageDir, "none", true); //$NON-NLS-1$
 					tmp.open(false);
 					dataFile = tmp.lookup(fileName, false);
 					tmp.close();
 				}
 			}
 			if (dataFile == null || !dataFile.isFile())
 				return true;
 			if (FILE_APPLOCKS.equals(fileName))
 				loadLocks(dataFile);
 			else if (FILE_APPSCHEDULED.equals(fileName))
 				loadSchedules(dataFile);
 		} catch (IOException e) {
 			return false;
 		}
 		return true;
 	}

 	private static void loadLocks(File locksData) throws IOException {
 		ObjectInputStream in = null;
 		try {
 			in = new ObjectInputStream(new FileInputStream(locksData));
 			int dataVersion = in.readInt();
 			if (dataVersion != DATA_VERSION)
 				return;
 			int numLocks = in.readInt();
 			synchronized (locks) {
 				for (int i = 0; i < numLocks; i++)
 					locks.add(in.readUTF());
 			}
 		} finally {
 			if (in != null)
 				in.close();
 		}
 	}

 	private static void loadSchedules(File schedulesData) throws IOException {
 		ObjectInputStream in = null;
 		try {
 			in = new ObjectInputStream(new FileInputStream(schedulesData));
 			int dataVersion = in.readInt();
 			if (dataVersion != DATA_VERSION)
 				return;
 			int numScheds = in.readInt();
 			for (int i = 0; i < numScheds; i++) {
 				String id = readString(in, false);
 				String appPid = readString(in, false);
 				String topic = readString(in, false);
 				String eventFilter = readString(in, false);
 				boolean recurring = in.readBoolean();
 				Map args = (Map) in.readObject();
 				EclipseScheduledApplication schedApp = new EclipseScheduledApplication(context, id, appPid, args, topic, eventFilter, recurring);
 				addScheduledApp(schedApp);
 			}
 		} catch (InvalidSyntaxException e) {
 			throw new IOException(e.getMessage());
 		} catch (NoClassDefFoundError e) {
 			throw new IOException(e.getMessage());
 		} catch (ClassNotFoundException e) {
 			throw new IOException(e.getMessage());
 		} finally {
 			if (in != null)
 				in.close();
 		}
 	}

 	private synchronized static void saveData(String fileName) {
 		if (storageManager == null || storageManager.isReadOnly())
 			return;
 		try {
 			File data = storageManager.createTempFile(fileName);
 			if (FILE_APPLOCKS.equals(fileName))
 				saveLocks(data);
 			else if (FILE_APPSCHEDULED.equals(fileName))
 				saveSchedules(data);
 			storageManager.lookup(fileName, true);
 			storageManager.update(new String[] {fileName}, new String[] {data.getName()});
 		} catch (IOException e) {
 			Activator.log(new FrameworkLogEntry(Activator.PI_APP, FrameworkLogEntry.ERROR, 0, NLS.bind(Messages.persistence_error_saving, fileName), 0, e, null));
 		}
 	}

 	// must call this while holding the locks lock
 	private static void saveLocks(File locksData) throws IOException {
 		ObjectOutputStream out = null;
 		try {
 			out = new ObjectOutputStream(new FileOutputStream(locksData));
 			out.writeInt(DATA_VERSION);
 			out.writeInt(locks.size());
 			for (Iterator iterLocks = locks.iterator(); iterLocks.hasNext();)
 				out.writeUTF((String) iterLocks.next());
 		} finally {
 			if (out != null)
 				out.close();
 		}
 	}

 	// must call this while holding the scheduledApps lock
 	private static void saveSchedules(File schedulesData) throws IOException {
 		ObjectOutputStream out = null;
 		try {
 			out = new ObjectOutputStream(new FileOutputStream(schedulesData));
 			out.writeInt(DATA_VERSION);
 			out.writeInt(scheduledApps.size());
 			for (Iterator apps = scheduledApps.values().iterator(); apps.hasNext();) {
 				EclipseScheduledApplication app = (EclipseScheduledApplication) apps.next();
 				writeStringOrNull(out, app.getScheduleId());
 				writeStringOrNull(out, app.getAppPid());
 				writeStringOrNull(out, app.getTopic());
 				writeStringOrNull(out, app.getEventFilter());
 				out.writeBoolean(app.isRecurring());
 				out.writeObject(app.getArguments());
 			}
 		} finally {
 			if (out != null)
 				out.close();
 		}
 	}

 	private static void startTimer() {
 		timerThread = new Thread(new AppTimer(), "app schedule timer"); //$NON-NLS-1$
 		timerThread.start();
 	}

 	private static void stopTimer() {
 		if (timerThread != null)
 			timerThread.interrupt();
 		timerThread = null;
 	}

 	static class AppTimer implements Runnable {
 		public void run() {
 			int lastMin = -1;
 			while (!shutdown) {
 				try {
 					Thread.sleep(30000); // sleeping 30 secs instead of 60 to try to avoid skipping minutes
 					Calendar cal = Calendar.getInstance();
 					int minute = cal.get(Calendar.MINUTE);
 					if (minute == lastMin)
 						continue;
 					lastMin = minute;
 					Hashtable props = new Hashtable();
 					props.put(ScheduledApplication.YEAR, new Integer(cal.get(Calendar.YEAR)));
 					props.put(ScheduledApplication.MONTH, new Integer(cal.get(Calendar.MONTH)));
 					props.put(ScheduledApplication.DAY_OF_MONTH, new Integer(cal.get(Calendar.DAY_OF_MONTH)));
 					props.put(ScheduledApplication.DAY_OF_WEEK, new Integer(cal.get(Calendar.DAY_OF_WEEK)));
 					props.put(ScheduledApplication.HOUR_OF_DAY, new Integer(cal.get(Calendar.HOUR_OF_DAY)));
 					props.put(ScheduledApplication.MINUTE, new Integer(minute));
 					Event timerEvent = new Event(ScheduledApplication.TIMER_TOPIC, (Dictionary) props);
 					EclipseScheduledApplication[] apps = null;
 					// poor mans implementation of dispatching events; the spec will not allow us to use event admin to dispatch the virtual timer events; boo!!
 					synchronized (timerApps) {
 						if (timerApps.size() == 0)
 							continue;
 						apps = (EclipseScheduledApplication[]) timerApps.toArray(new EclipseScheduledApplication[timerApps.size()]);
 					}
 					for (int i = 0; i < apps.length; i++) {
 						try {
 							String filterString = apps[i].getEventFilter();
 							Filter filter = filterString == null ? null : FrameworkUtil.createFilter(filterString);
 							if (filter == null || filter.match(props))
 								apps[i].handleEvent(timerEvent);
 						} catch (Throwable t) {
 							String message = NLS.bind(Messages.scheduled_app_launch_error, apps[i].getAppPid());
 							Activator.log(new FrameworkLogEntry(Activator.PI_APP, FrameworkLogEntry.WARNING, 0, message, 0, t, null));
 						}
 					}
 				} catch (InterruptedException e) {
 					// do nothing;
 				}
 			}
 		}
 	}

 	private static String readString(ObjectInputStream in, boolean intern) throws IOException {
 		byte type = in.readByte();
 		if (type == NULL)
 			return null;
 		return intern ? in.readUTF().intern() : in.readUTF();
 	}

 	private static void writeStringOrNull(ObjectOutputStream out, String string) throws IOException {
 		if (string == null)
 			out.writeByte(NULL);
 		else {
 			out.writeByte(OBJECT);
 			out.writeUTF(string);
 		}
 	}

 	public Object addingService(ServiceReference reference) {
 		if (configLocation != null)
 			return null; // only care about one configuration
 		configLocation = (Location) context.getService(reference);
 		loadData(FILE_APPLOCKS);
 		loadData(FILE_APPSCHEDULED);
 		return configLocation;
 	}

 	public void modifiedService(ServiceReference reference, Object service) {
 		// don't care
 	}

 	public void removedService(ServiceReference reference, Object service) {
 		if (service == configLocation)
 			configLocation = null;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005, 2009 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.equinox.internal.app;

	import java.io.*;
	import java.util.*;
	import org.eclipse.osgi.framework.log.FrameworkLogEntry;
	import org.eclipse.osgi.service.datalocation.Location;
	import org.eclipse.osgi.storagemanager.StorageManager;
	import org.eclipse.osgi.util.NLS;
	import org.osgi.framework.*;
	import org.osgi.service.application.*;
	import org.osgi.service.event.Event;
	import org.osgi.service.event.EventConstants;
	import org.osgi.util.tracker.ServiceTracker;
	import org.osgi.util.tracker.ServiceTrackerCustomizer;

	/**
	* Manages all persistent data for ApplicationDescriptors (lock status,
	* scheduled applications etc.)
	*/
	public class AppPersistence implements ServiceTrackerCustomizer {
	private static final String PROP_CONFIG_AREA = "osgi.configuration.area"; //$NON-NLS-1$

	private static final String FILTER_PREFIX = "(&(objectClass=org.eclipse.osgi.service.datalocation.Location)(type="; //$NON-NLS-1$
	private static final String FILE_APPLOCKS = ".locks"; //$NON-NLS-1$
	private static final String FILE_APPSCHEDULED = ".scheduled"; //$NON-NLS-1$
	private static final String EVENT_HANDLER = "org.osgi.service.event.EventHandler"; //$NON-NLS-1$

	private static final int DATA_VERSION = 2;
	private static final byte NULL = 0;
	private static final int OBJECT = 1;

	private static BundleContext context;
	private static ServiceTracker configTracker;
	private static Location configLocation;
	private static Collection locks = new ArrayList();
	private static Map scheduledApps = new HashMap();
	static ArrayList timerApps = new ArrayList();
	private static StorageManager storageManager;
	private static boolean scheduling = false;
	static boolean shutdown = false;
	private static int nextScheduledID = 1;
	private static Thread timerThread;

	static void start(BundleContext bc) {
	context = bc;
	shutdown = false;
	initConfiguration();
	}

	static void stop() {
	shutdown = true;
	stopTimer();
	if (storageManager != null) {
	storageManager.close();
	storageManager = null;
	}
	closeConfiguration();
	context = null;
	}

	private static void initConfiguration() {
	closeConfiguration(); // just incase
	Filter filter = null;
	try {
	filter = context.createFilter(FILTER_PREFIX + PROP_CONFIG_AREA + "))"); //$NON-NLS-1$
	} catch (InvalidSyntaxException e) {
	// ignore this. It should never happen as we have tested the above format.
	}
	configTracker = new ServiceTracker(context, filter, new AppPersistence());
	configTracker.open();
	}

	private static void closeConfiguration() {
	if (configTracker != null)
	configTracker.close();
	configTracker = null;
	}

	/**
	* Used by {@link ApplicationDescriptor} to determine if an application is locked.
	* @param desc the application descriptor
	* @return true if the application is persistently locked.
	*/
	public static boolean isLocked(ApplicationDescriptor desc) {
	synchronized (locks) {
	return locks.contains(desc.getApplicationId());
	}
	}

	/**
	* Used by {@link ApplicationDescriptor} to determine lock and unlock and application.
	* @param desc the application descriptor
	* @param locked the locked flag
	*/
	public static void saveLock(ApplicationDescriptor desc, boolean locked) {
	synchronized (locks) {
	if (locked) {
	if (!locks.contains(desc.getApplicationId())) {
	locks.add(desc.getApplicationId());
	saveData(FILE_APPLOCKS);
	}
	} else if (locks.remove(desc.getApplicationId())) {
	saveData(FILE_APPLOCKS);
	}
	}
	}

	static void removeScheduledApp(EclipseScheduledApplication scheduledApp) {
	boolean removed;
	synchronized (scheduledApps) {
	removed = scheduledApps.remove(scheduledApp.getScheduleId()) != null;
	if (removed) {
	saveData(FILE_APPSCHEDULED);
	}
	}
	if (removed)
	synchronized (timerApps) {
	timerApps.remove(scheduledApp);
	}
	}

	/**
	* Used by {@link ScheduledApplication} to persistently schedule an application launch
	* @param descriptor
	* @param arguments
	* @param topic
	* @param eventFilter
	* @param recurring
	* @return the scheduled application
	* @throws InvalidSyntaxException
	* @throws ApplicationException
	*/
	public static ScheduledApplication addScheduledApp(ApplicationDescriptor descriptor, String scheduleId, Map arguments, String topic, String eventFilter, boolean recurring) throws InvalidSyntaxException, ApplicationException {
	if (!scheduling && !checkSchedulingSupport())
	throw new ApplicationException(ApplicationException.APPLICATION_SCHEDULING_FAILED, "Cannot support scheduling without org.osgi.service.event package"); //$NON-NLS-1$
	// check the event filter for correct syntax
	context.createFilter(eventFilter);
	EclipseScheduledApplication result;
	synchronized (scheduledApps) {
	result = new EclipseScheduledApplication(context, getNextScheduledID(scheduleId), descriptor.getApplicationId(), arguments, topic, eventFilter, recurring);
	addScheduledApp(result);
	saveData(FILE_APPSCHEDULED);
	}
	return result;
	}

	// must call this method while holding the scheduledApps lock
	private static void addScheduledApp(EclipseScheduledApplication scheduledApp) {
	if (ScheduledApplication.TIMER_TOPIC.equals(scheduledApp.getTopic())) {
	synchronized (timerApps) {
	timerApps.add(scheduledApp);
	if (timerThread == null)
	startTimer();
	}
	}
	scheduledApps.put(scheduledApp.getScheduleId(), scheduledApp);
	Hashtable serviceProps = new Hashtable();
	if (scheduledApp.getTopic() != null)
	serviceProps.put(EventConstants.EVENT_TOPIC, new String[] {scheduledApp.getTopic()});
	if (scheduledApp.getEventFilter() != null)
	serviceProps.put(EventConstants.EVENT_FILTER, scheduledApp.getEventFilter());
	serviceProps.put(ScheduledApplication.SCHEDULE_ID, scheduledApp.getScheduleId());
	serviceProps.put(ScheduledApplication.APPLICATION_PID, scheduledApp.getAppPid());
	ServiceRegistration sr = context.registerService(new String[] {ScheduledApplication.class.getName(), EVENT_HANDLER}, scheduledApp, serviceProps);
	scheduledApp.setServiceRegistration(sr);
	}

	private static String getNextScheduledID(String scheduledId) throws ApplicationException {
	if (scheduledId != null) {
	if (scheduledApps.get(scheduledId) != null)
	throw new ApplicationException(ApplicationException.APPLICATION_DUPLICATE_SCHEDULE_ID, "Duplicate scheduled ID: " + scheduledId); //$NON-NLS-1$
	return scheduledId;
	}
	if (nextScheduledID == Integer.MAX_VALUE)
	nextScheduledID = 0;
	String result = new Integer(nextScheduledID++).toString();
	while (scheduledApps.get(result) != null && nextScheduledID < Integer.MAX_VALUE)
	result = new Integer(nextScheduledID++).toString();
	if (nextScheduledID == Integer.MAX_VALUE)
	throw new ApplicationException(ApplicationException.APPLICATION_DUPLICATE_SCHEDULE_ID, "Maximum number of scheduled applications reached"); //$NON-NLS-1$
	return result;
	}

	private static boolean checkSchedulingSupport() {
	// cannot support scheduling without the event admin package
	try {
	Class.forName(EVENT_HANDLER);
	scheduling = true;
	return true;
	} catch (ClassNotFoundException e) {
	scheduling = false;
	return false;
	}
	}

	private synchronized static boolean loadData(String fileName) {
	try {
	Location location = configLocation;
	if (location == null)
	return false;
	File theStorageDir = new File(location.getURL().getPath() + '/' + Activator.PI_APP);
	if (storageManager == null) {
	boolean readOnly = location.isReadOnly();
	storageManager = new StorageManager(theStorageDir, readOnly ? "none" : null, readOnly); //$NON-NLS-1$
	storageManager.open(!readOnly);
	}
	File dataFile = storageManager.lookup(fileName, false);
	if (dataFile == null \|\| !dataFile.isFile()) {
	Location parent = location.getParentLocation();
	if (parent != null) {
	theStorageDir = new File(parent.getURL().getPath() + '/' + Activator.PI_APP);
	StorageManager tmp = new StorageManager(theStorageDir, "none", true); //$NON-NLS-1$
	tmp.open(false);
	dataFile = tmp.lookup(fileName, false);
	tmp.close();
	}
	}
	if (dataFile == null \|\| !dataFile.isFile())
	return true;
	if (FILE_APPLOCKS.equals(fileName))
	loadLocks(dataFile);
	else if (FILE_APPSCHEDULED.equals(fileName))
	loadSchedules(dataFile);
	} catch (IOException e) {
	return false;
	}
	return true;
	}

	private static void loadLocks(File locksData) throws IOException {
	ObjectInputStream in = null;
	try {
	in = new ObjectInputStream(new FileInputStream(locksData));
	int dataVersion = in.readInt();
	if (dataVersion != DATA_VERSION)
	return;
	int numLocks = in.readInt();
	synchronized (locks) {
	for (int i = 0; i < numLocks; i++)
	locks.add(in.readUTF());
	}
	} finally {
	if (in != null)
	in.close();
	}
	}

	private static void loadSchedules(File schedulesData) throws IOException {
	ObjectInputStream in = null;
	try {
	in = new ObjectInputStream(new FileInputStream(schedulesData));
	int dataVersion = in.readInt();
	if (dataVersion != DATA_VERSION)
	return;
	int numScheds = in.readInt();
	for (int i = 0; i < numScheds; i++) {
	String id = readString(in, false);
	String appPid = readString(in, false);
	String topic = readString(in, false);
	String eventFilter = readString(in, false);
	boolean recurring = in.readBoolean();
	Map args = (Map) in.readObject();
	EclipseScheduledApplication schedApp = new EclipseScheduledApplication(context, id, appPid, args, topic, eventFilter, recurring);
	addScheduledApp(schedApp);
	}
	} catch (InvalidSyntaxException e) {
	throw new IOException(e.getMessage());
	} catch (NoClassDefFoundError e) {
	throw new IOException(e.getMessage());
	} catch (ClassNotFoundException e) {
	throw new IOException(e.getMessage());
	} finally {
	if (in != null)
	in.close();
	}
	}

	private synchronized static void saveData(String fileName) {
	if (storageManager == null \|\| storageManager.isReadOnly())
	return;
	try {
	File data = storageManager.createTempFile(fileName);
	if (FILE_APPLOCKS.equals(fileName))
	saveLocks(data);
	else if (FILE_APPSCHEDULED.equals(fileName))
	saveSchedules(data);
	storageManager.lookup(fileName, true);
	storageManager.update(new String[] {fileName}, new String[] {data.getName()});
	} catch (IOException e) {
	Activator.log(new FrameworkLogEntry(Activator.PI_APP, FrameworkLogEntry.ERROR, 0, NLS.bind(Messages.persistence_error_saving, fileName), 0, e, null));
	}
	}

	// must call this while holding the locks lock
	private static void saveLocks(File locksData) throws IOException {
	ObjectOutputStream out = null;
	try {
	out = new ObjectOutputStream(new FileOutputStream(locksData));
	out.writeInt(DATA_VERSION);
	out.writeInt(locks.size());
	for (Iterator iterLocks = locks.iterator(); iterLocks.hasNext();)
	out.writeUTF((String) iterLocks.next());
	} finally {
	if (out != null)
	out.close();
	}
	}

	// must call this while holding the scheduledApps lock
	private static void saveSchedules(File schedulesData) throws IOException {
	ObjectOutputStream out = null;
	try {
	out = new ObjectOutputStream(new FileOutputStream(schedulesData));
	out.writeInt(DATA_VERSION);
	out.writeInt(scheduledApps.size());
	for (Iterator apps = scheduledApps.values().iterator(); apps.hasNext();) {
	EclipseScheduledApplication app = (EclipseScheduledApplication) apps.next();
	writeStringOrNull(out, app.getScheduleId());
	writeStringOrNull(out, app.getAppPid());
	writeStringOrNull(out, app.getTopic());
	writeStringOrNull(out, app.getEventFilter());
	out.writeBoolean(app.isRecurring());
	out.writeObject(app.getArguments());
	}
	} finally {
	if (out != null)
	out.close();
	}
	}

	private static void startTimer() {
	timerThread = new Thread(new AppTimer(), "app schedule timer"); //$NON-NLS-1$
	timerThread.start();
	}

	private static void stopTimer() {
	if (timerThread != null)
	timerThread.interrupt();
	timerThread = null;
	}

	static class AppTimer implements Runnable {
	public void run() {
	int lastMin = -1;
	while (!shutdown) {
	try {
	Thread.sleep(30000); // sleeping 30 secs instead of 60 to try to avoid skipping minutes
	Calendar cal = Calendar.getInstance();
	int minute = cal.get(Calendar.MINUTE);
	if (minute == lastMin)
	continue;
	lastMin = minute;
	Hashtable props = new Hashtable();
	props.put(ScheduledApplication.YEAR, new Integer(cal.get(Calendar.YEAR)));
	props.put(ScheduledApplication.MONTH, new Integer(cal.get(Calendar.MONTH)));
	props.put(ScheduledApplication.DAY_OF_MONTH, new Integer(cal.get(Calendar.DAY_OF_MONTH)));
	props.put(ScheduledApplication.DAY_OF_WEEK, new Integer(cal.get(Calendar.DAY_OF_WEEK)));
	props.put(ScheduledApplication.HOUR_OF_DAY, new Integer(cal.get(Calendar.HOUR_OF_DAY)));
	props.put(ScheduledApplication.MINUTE, new Integer(minute));
	Event timerEvent = new Event(ScheduledApplication.TIMER_TOPIC, (Dictionary) props);
	EclipseScheduledApplication[] apps = null;
	// poor mans implementation of dispatching events; the spec will not allow us to use event admin to dispatch the virtual timer events; boo!!
	synchronized (timerApps) {
	if (timerApps.size() == 0)
	continue;
	apps = (EclipseScheduledApplication[]) timerApps.toArray(new EclipseScheduledApplication[timerApps.size()]);
	}
	for (int i = 0; i < apps.length; i++) {
	try {
	String filterString = apps[i].getEventFilter();
	Filter filter = filterString == null ? null : FrameworkUtil.createFilter(filterString);
	if (filter == null \|\| filter.match(props))
	apps[i].handleEvent(timerEvent);
	} catch (Throwable t) {
	String message = NLS.bind(Messages.scheduled_app_launch_error, apps[i].getAppPid());
	Activator.log(new FrameworkLogEntry(Activator.PI_APP, FrameworkLogEntry.WARNING, 0, message, 0, t, null));
	}
	}
	} catch (InterruptedException e) {
	// do nothing;
	}
	}
	}
	}

	private static String readString(ObjectInputStream in, boolean intern) throws IOException {
	byte type = in.readByte();
	if (type == NULL)
	return null;
	return intern ? in.readUTF().intern() : in.readUTF();
	}

	private static void writeStringOrNull(ObjectOutputStream out, String string) throws IOException {
	if (string == null)
	out.writeByte(NULL);
	else {
	out.writeByte(OBJECT);
	out.writeUTF(string);
	}
	}

	public Object addingService(ServiceReference reference) {
	if (configLocation != null)
	return null; // only care about one configuration
	configLocation = (Location) context.getService(reference);
	loadData(FILE_APPLOCKS);
	loadData(FILE_APPSCHEDULED);
	return configLocation;
	}

	public void modifiedService(ServiceReference reference, Object service) {
	// don't care
	}

	public void removedService(ServiceReference reference, Object service) {
	if (service == configLocation)
	configLocation = null;
	}
	}