Esempio n. 1
0
class ZUserPreferencesBase(IZUserPreferences):

    def __init__(self):
        self.listeners = ZListenerSet()
    # end __init__()

    def addListener(self, listener):
        self.listeners.addListener(listener)
    # end addListener()

    def removeListener(self, listener):
        self.listeners.removeListener(listener)
    # end removeListener()

    def getUserPreference(self, key, dflt = None):
        rval = self._getUserPreference(key)
        if rval is None:
            rval = dflt
        return rval
    # end getUserPreference()

    def getUserPreferenceBool(self, key, dflt = None):
        value = self.getUserPreference(key, None)
        if value is None:
            return dflt
        return value == u"True" or value == u"true" #$NON-NLS-2$ #$NON-NLS-1$
    # end getUserPreferenceBool()

    def getUserPreferenceInt(self, key, dflt = None):
        value = self.getUserPreference(key, None)
        if value is None:
            return dflt
        try:
            return string.atoi(value)
        except:
            return dflt
    # end getUserPreferenceInt

    def setUserPreference(self, key, value):
        self.listeners.doCallback(u"onUserPreferenceChange", [key, value]) #$NON-NLS-1$
        if value is not None:
            value = unicode(value)
        self._setUserPreference(key, value)
    # end setUserPreference()

    def removeUserPreference(self, key):
        self._removeUserPreference(key)
    # end removeUserPreference()

    def _getUserPreference(self, key):
        u"Internal method to get the value of the user preference.  If it does not exist, this should return None." #$NON-NLS-1$
        raise ZAbstractMethodCalledException(unicode(self.__class__), u"_getUserPreference") #$NON-NLS-1$
    # end _getUserPreference()

    def _setUserPreference(self, key, value):
        u"Internal method to set the value of the user preference." #$NON-NLS-1$
        raise ZAbstractMethodCalledException(unicode(self.__class__), u"_setUserPreference") #$NON-NLS-1$
    # end _setUserPreference()

    def _removeUserPreference(self, key):
        u"Internal method to remove the value of the user preference." #$NON-NLS-1$
        raise ZAbstractMethodCalledException(unicode(self.__class__), u"_removeUserPreference") #$NON-NLS-1$
Esempio n. 2
0
class ZBackgroundTaskService(IZBackgroundTaskService,
                             IZBackgroundTaskListener):
    def __init__(self):
        self.logger = None
        self.tasksDirectory = None
        self.tasks = []
        self.listeners = ZListenerSet()

    # end __init__()

    def _getTasksDirectory(self, applicationModel):
        return applicationModel.getUserProfile().getDirectory(
            u"bgtasks")  #$NON-NLS-1$

    # end _getTasksDirectory()

    def addListener(self, listener):
        self.listeners.append(listener)

    # end addListener()

    def removeListener(self, listener):
        self.listeners.remove(listener)

    # end removeListener()

    def start(self, applicationModel):
        self.logger = applicationModel.getEngine().getService(
            IZAppServiceIDs.LOGGER_SERVICE_ID)
        self.tasksDirectory = self._getTasksDirectory(applicationModel)
        self.tasks = self._loadTasks()
        self.logger.debug(
            u"Background Task Service started [%d tasks loaded]." %
            len(self.tasks))  #$NON-NLS-1$

    # end start()

    def stop(self):
        # First, stop all tasks.
        for task in self.tasks:
            if task.isRunning():
                task.stop()

        self.tasks = []

    # end stop()

    def getTasks(self):
        return self.tasks

    # end getTasks()

    def getTask(self, taskId):
        for task in self.tasks:
            if task.getId() == taskId:
                return task
        return None

    # end getTask()

    def addTask(self, task):
        task.setId(generate())
        taskLogFilename = os.path.join(self.tasksDirectory,
                                       task.getId() +
                                       u".task.log")  #$NON-NLS-1$
        task.setLogLocation(taskLogFilename)
        self.tasks.append(task)

        self.listeners.doCallback(u"onTaskAdded", [task])  #$NON-NLS-1$
        self._resumeTask(task)

        # Wait until the num work units has been set by the task (but only
        # wait for up to 30 seconds).
        numWaits = 0
        while task.getNumWorkUnits() <= 0 and numWaits < 60:
            time.sleep(0.5)
            numWaits = numWaits + 1
        if task.getNumWorkUnits() <= 0:
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.TaskFailedToStartError") %
                task.getName())  #$NON-NLS-1$

    # end addTask()

    def cancelTask(self, taskId, removeFlag=False):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToCancelDoesNotExist") %
                taskId)  #$NON-NLS-1$
        task.cancel()
        task.detachListener(self)
        self.listeners.doCallback(u"onTaskCancelled", [task])  #$NON-NLS-1$
        if removeFlag:
            self.removeTask(taskId)

    # end cancelTask()

    def removeTask(self, taskId):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToRemoveDoesNotExist") %
                taskId)  #$NON-NLS-1$
        if task.isRunning():
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToRemoveStillRunning") %
                taskId)  #$NON-NLS-1$
        self.tasks.remove(task)

        self._removeTask(task)

        self.listeners.doCallback(u"onTaskRemoved", [task])  #$NON-NLS-1$

    # end removeTask()

    def resumeTask(self, taskId, listener=None):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToResumeTaskNotFound") %
                taskId)  #$NON-NLS-1$
        if task.isRunning():
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToResumeTaskAlreadyRunning")
                % taskId)  #$NON-NLS-1$
        if task.isComplete():
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToResumeTaskComplete") %
                taskId)  #$NON-NLS-1$
        if not task.isResumable():
            raise ZAppFrameworkException(
                _extstr(u"backgroundtaskimpl.FailedToResumeTaskNotResumable") %
                taskId)  #$NON-NLS-1$
        if listener is not None:
            task.attachListener(listener)
        self._resumeTask(task)

        self.listeners.doCallback(u"onTaskResumed", [task])  #$NON-NLS-1$

        return task

    # end resumeTask()

    def _loadTasks(self):
        tasks = []

        taskFiles = getDirectoryListing(self.tasksDirectory, TASK_FILE_FILTER)
        for taskFile in taskFiles:
            try:
                task = self._loadTask(taskFile)
                # Restart any resumable (but not cancelled) tasks.
                if task.isResumable() and not task.isCancelled(
                ) and not task.isComplete() and not task.hasError():
                    self._resumeTask(task)
                tasks.append(task)
            except Exception, e:
                self.logger.exception(e)

        return tasks
Esempio n. 3
0
class ZBackgroundTask(IZBackgroundTask):

    def __init__(self):
        self.id = None
        self.name = None
        self.startTime = ZSchemaDateTime()
        self.endTime = None
        self.error = None
        self.numWorkUnits = 0
        self.numCompletedWorkUnits = 0
        self.logLocation = None
        self.logFile = None
        self.running = False
        self.stopped = True
        self.cancelled = False
        self.lastMessage = None
        self.listeners = ZListenerSet()
        self.logger = getLoggerService()
    # end __init__()

    def getId(self):
        return self.id
    # end getId()

    def setId(self, id):
        self.id = id
    # end setId()

    def getName(self):
        return self.name
    # end getName()

    def setName(self, name):
        self.name = name
    # end setName()

    def getStartTime(self):
        return self.startTime
    # end getStartTime()

    def setStartTime(self, startTime):
        self.startTime = startTime
    # end setStartTime()

    def getEndTime(self):
        return self.endTime
    # end getEndTime()

    def setEndTime(self, endTime):
        self.endTime = endTime
    # end setEndTime()

    def getNumWorkUnits(self):
        return self.numWorkUnits
    # end getNumWorkUnits()

    def setNumWorkUnits(self, numWorkUnits):
        self.numWorkUnits = numWorkUnits
    # end setNumWorkUnits()

    def getNumCompletedWorkUnits(self):
        return self.numCompletedWorkUnits
    # end getNumCompletedWorkUnits()

    def setNumCompletedWorkUnits(self, numCompletedWorkUnits):
        self.numCompletedWorkUnits = numCompletedWorkUnits
    # end setNumCompletedWorkUnits()

    def getLogLocation(self):
        return self.logLocation
    # end getLog()

    def setLogLocation(self, logLocation):
        self.logLocation = logLocation
    # end setLog()

    def getLogFile(self):
        if self.logFile is None and self.logLocation is not None:
            self.logFile = codecs.open(self.logLocation, u"aa", u"utf-8") #$NON-NLS-2$ #$NON-NLS-1$
        return self.logFile
    # end getLogFile()

    def getLastLogMessage(self):
        return self.lastMessage
    # end getLastLogMessage()

    def getCustomAttributes(self):
        raise ZAppFrameworkException(u"Subclass should implement this!") #$NON-NLS-1$
    # end getCustomAttributes()

    def setCustomAttributes(self, attributeMap):
        raise ZAppFrameworkException(u"Subclass should implement this!") #$NON-NLS-1$
    # end setCustomAttributes()

    def isRunning(self):
        return self.running
    # end isRunning()

    def isCancelled(self):
        return self.cancelled
    # end isCancelled()

    def setCancelled(self, cancelled = True):
        self.cancelled = cancelled
    # end setCancelled()

    def isComplete(self):
        return self.numCompletedWorkUnits == self.numWorkUnits
    # end isComplete()

    def isResumable(self):
        raise ZAppFrameworkException(u"Subclass should implement this!") #$NON-NLS-1$
    # end isResumable()

    def getError(self):
        return self.error
    # end getError()

    def setError(self, errorMessage, errorDetails):
        self.error = (errorMessage, errorDetails)
    # end setError()

    def hasError(self):
        return self.error is not None
    # end hasError()

    def stop(self):
        self.logger.debug(u"[bgtask.%s] Stopping task." % (self.getName())) #$NON-NLS-1$
        self.stopped = True

        # This should really be a wait/notify
        while self.running:
            time.sleep(0.25)
    # end stop()

    def _doCancel(self):
        u"Subclasses can override in order to provide additional cancel logic." #$NON-NLS-1$
    # end _doCancel()

    def cancel(self):
        self.logger.debug(u"[bgtask.%s] Cancelling task." % (self.getName())) #$NON-NLS-1$
        self.stopped = True
        self.cancelled = True

        self._doCancel()

        # This should really be a wait/notify
        while self.running:
            time.sleep(0.25)

        # Notify the listeners.
        self.listeners.doCallback(u"onCancel", [self]) #$NON-NLS-1$
    # end cancel()

    def cancelAsync(self):
        thread = ZThread(ZMethodRunnable(self.cancel), u"CancelTask", True) #$NON-NLS-1$
        thread.start()
    # end cancelAsync()

    def attachListener(self, listener):
        self.listeners._acquireMutex()
        try:
            self.listeners.append(listener)
            listener.onAttached(self, self.numCompletedWorkUnits)
        finally:
            self.listeners._releaseMutex()
    # end attachListener()

    def detachListener(self, listener):
        self.listeners.remove(listener)
    # end detachListener()

    # Convenience method to indicate that work has been done.
    #
    # message: the message to send to the listeners (and optionally log)
    # amount: amount of work that was done
    # logMessage: flag indicating whether this message should be logged (useful for tasks that do a LOT
    #             of work but only want to log certain vital messages)
    def _incrementWork(self, message, amount = 1, logMessage = True):
        if self.isCancelled():
            return
        self.lastMessage = message
        self.numCompletedWorkUnits = self.numCompletedWorkUnits + amount
        self.listeners.doCallback(u"onWorkDone", [self, amount, message]) #$NON-NLS-1$
        if logMessage:
            self._writeToLog(message)

        if self.numCompletedWorkUnits == self.numWorkUnits:
            self.stopped = True
            self.endTime = ZSchemaDateTime()
            self.listeners.doCallback(u"onComplete", [self]) #$NON-NLS-1$
    # end _incrementWork()

    # Convenience method to raise an error message.  This will notify the listeners of the
    # error, cancel the task, and log the error message.
    def _raiseError(self, errorMessage, errorDetails):
        self.logger.error(errorMessage)
        self.error = (errorMessage, errorDetails)
        self.listeners.doCallback(u"onError", [self, errorMessage, errorDetails]) #$NON-NLS-1$
        self._writeToLog(_extstr(u"backgroundtaskimpl.ErrorInTask") % errorMessage) #$NON-NLS-1$
        self._writeToLog(errorDetails)
        self.endTime = ZSchemaDateTime()
        self.stopped = True
        self.cancelled = True
    # end _raiseError()

    # Reports an exception (when the _run() method throws).
    def _reportException(self, exception):
        if not isinstance(exception, ZException):
            exception = ZException(_extstr(u"backgroundtaskimpl.UnexpectedBGTaskError") % self.getName(), exception) #$NON-NLS-1$
        self.logger.exception(exception)

        self._raiseError(exception.getMessage(), exception.getStackTrace())
    # end _reportException()

    def _writeToLog(self, message):
        self.logger.debug(u"[bgtask.%s] %s" % (self.getName(), message)) #$NON-NLS-1$
        if message is not None and self.getLogFile() is not None:
            self.getLogFile().write(message)
            self.getLogFile().write(u"\n") #$NON-NLS-1$
            self.getLogFile().flush()
    # end _writeToLog()

    def run(self):
        self._writeToLog(u"[bgtask.%s] Task started: %s" % (self.getName(), unicode(ZSchemaDateTime()))) #$NON-NLS-1$
        # Send the 'onStarted' event.
        self._fireStartEvent()

        # Run the actual task logic here.
        try:
            self._run()
        except ZException, ze:
            self._reportException(ze)
        except Exception, e:
            self._reportException(ZException(_extstr(u"backgroundtaskimpl.ErrorExecingTask") % self.getName(), e)) #$NON-NLS-1$
Esempio n. 4
0
class ZBackgroundTask(IZBackgroundTask):
    def __init__(self):
        self.id = None
        self.name = None
        self.startTime = ZSchemaDateTime()
        self.endTime = None
        self.error = None
        self.numWorkUnits = 0
        self.numCompletedWorkUnits = 0
        self.logLocation = None
        self.logFile = None
        self.running = False
        self.stopped = True
        self.cancelled = False
        self.lastMessage = None
        self.listeners = ZListenerSet()
        self.logger = getLoggerService()

    # end __init__()

    def getId(self):
        return self.id

    # end getId()

    def setId(self, id):
        self.id = id

    # end setId()

    def getName(self):
        return self.name

    # end getName()

    def setName(self, name):
        self.name = name

    # end setName()

    def getStartTime(self):
        return self.startTime

    # end getStartTime()

    def setStartTime(self, startTime):
        self.startTime = startTime

    # end setStartTime()

    def getEndTime(self):
        return self.endTime

    # end getEndTime()

    def setEndTime(self, endTime):
        self.endTime = endTime

    # end setEndTime()

    def getNumWorkUnits(self):
        return self.numWorkUnits

    # end getNumWorkUnits()

    def setNumWorkUnits(self, numWorkUnits):
        self.numWorkUnits = numWorkUnits

    # end setNumWorkUnits()

    def getNumCompletedWorkUnits(self):
        return self.numCompletedWorkUnits

    # end getNumCompletedWorkUnits()

    def setNumCompletedWorkUnits(self, numCompletedWorkUnits):
        self.numCompletedWorkUnits = numCompletedWorkUnits

    # end setNumCompletedWorkUnits()

    def getLogLocation(self):
        return self.logLocation

    # end getLog()

    def setLogLocation(self, logLocation):
        self.logLocation = logLocation

    # end setLog()

    def getLogFile(self):
        if self.logFile is None and self.logLocation is not None:
            self.logFile = codecs.open(self.logLocation, u"aa",
                                       u"utf-8")  #$NON-NLS-2$ #$NON-NLS-1$
        return self.logFile

    # end getLogFile()

    def getLastLogMessage(self):
        return self.lastMessage

    # end getLastLogMessage()

    def getCustomAttributes(self):
        raise ZAppFrameworkException(
            u"Subclass should implement this!")  #$NON-NLS-1$

    # end getCustomAttributes()

    def setCustomAttributes(self, attributeMap):
        raise ZAppFrameworkException(
            u"Subclass should implement this!")  #$NON-NLS-1$

    # end setCustomAttributes()

    def isRunning(self):
        return self.running

    # end isRunning()

    def isCancelled(self):
        return self.cancelled

    # end isCancelled()

    def setCancelled(self, cancelled=True):
        self.cancelled = cancelled

    # end setCancelled()

    def isComplete(self):
        return self.numCompletedWorkUnits == self.numWorkUnits

    # end isComplete()

    def isResumable(self):
        raise ZAppFrameworkException(
            u"Subclass should implement this!")  #$NON-NLS-1$

    # end isResumable()

    def getError(self):
        return self.error

    # end getError()

    def setError(self, errorMessage, errorDetails):
        self.error = (errorMessage, errorDetails)

    # end setError()

    def hasError(self):
        return self.error is not None

    # end hasError()

    def stop(self):
        self.logger.debug(u"[bgtask.%s] Stopping task." %
                          (self.getName()))  #$NON-NLS-1$
        self.stopped = True

        # This should really be a wait/notify
        while self.running:
            time.sleep(0.25)

    # end stop()

    def _doCancel(self):
        u"Subclasses can override in order to provide additional cancel logic."  #$NON-NLS-1$

    # end _doCancel()

    def cancel(self):
        self.logger.debug(u"[bgtask.%s] Cancelling task." %
                          (self.getName()))  #$NON-NLS-1$
        self.stopped = True
        self.cancelled = True

        self._doCancel()

        # This should really be a wait/notify
        while self.running:
            time.sleep(0.25)

        # Notify the listeners.
        self.listeners.doCallback(u"onCancel", [self])  #$NON-NLS-1$

    # end cancel()

    def cancelAsync(self):
        thread = ZThread(ZMethodRunnable(self.cancel), u"CancelTask",
                         True)  #$NON-NLS-1$
        thread.start()

    # end cancelAsync()

    def attachListener(self, listener):
        self.listeners._acquireMutex()
        try:
            self.listeners.append(listener)
            listener.onAttached(self, self.numCompletedWorkUnits)
        finally:
            self.listeners._releaseMutex()

    # end attachListener()

    def detachListener(self, listener):
        self.listeners.remove(listener)

    # end detachListener()

    # Convenience method to indicate that work has been done.
    #
    # message: the message to send to the listeners (and optionally log)
    # amount: amount of work that was done
    # logMessage: flag indicating whether this message should be logged (useful for tasks that do a LOT
    #             of work but only want to log certain vital messages)
    def _incrementWork(self, message, amount=1, logMessage=True):
        if self.isCancelled():
            return
        self.lastMessage = message
        self.numCompletedWorkUnits = self.numCompletedWorkUnits + amount
        self.listeners.doCallback(u"onWorkDone",
                                  [self, amount, message])  #$NON-NLS-1$
        if logMessage:
            self._writeToLog(message)

        if self.numCompletedWorkUnits == self.numWorkUnits:
            self.stopped = True
            self.endTime = ZSchemaDateTime()
            self.listeners.doCallback(u"onComplete", [self])  #$NON-NLS-1$

    # end _incrementWork()

    # Convenience method to raise an error message.  This will notify the listeners of the
    # error, cancel the task, and log the error message.
    def _raiseError(self, errorMessage, errorDetails):
        self.logger.error(errorMessage)
        self.error = (errorMessage, errorDetails)
        self.listeners.doCallback(
            u"onError", [self, errorMessage, errorDetails])  #$NON-NLS-1$
        self._writeToLog(
            _extstr(u"backgroundtaskimpl.ErrorInTask") %
            errorMessage)  #$NON-NLS-1$
        self._writeToLog(errorDetails)
        self.endTime = ZSchemaDateTime()
        self.stopped = True
        self.cancelled = True

    # end _raiseError()

    # Reports an exception (when the _run() method throws).
    def _reportException(self, exception):
        if not isinstance(exception, ZException):
            exception = ZException(
                _extstr(u"backgroundtaskimpl.UnexpectedBGTaskError") %
                self.getName(), exception)  #$NON-NLS-1$
        self.logger.exception(exception)

        self._raiseError(exception.getMessage(), exception.getStackTrace())

    # end _reportException()

    def _writeToLog(self, message):
        self.logger.debug(u"[bgtask.%s] %s" %
                          (self.getName(), message))  #$NON-NLS-1$
        if message is not None and self.getLogFile() is not None:
            self.getLogFile().write(message)
            self.getLogFile().write(u"\n")  #$NON-NLS-1$
            self.getLogFile().flush()

    # end _writeToLog()

    def run(self):
        self._writeToLog(
            u"[bgtask.%s] Task started: %s" %
            (self.getName(), unicode(ZSchemaDateTime())))  #$NON-NLS-1$
        # Send the 'onStarted' event.
        self._fireStartEvent()

        # Run the actual task logic here.
        try:
            self._run()
        except ZException, ze:
            self._reportException(ze)
        except Exception, e:
            self._reportException(
                ZException(
                    _extstr(u"backgroundtaskimpl.ErrorExecingTask") %
                    self.getName(), e))  #$NON-NLS-1$
Esempio n. 5
0
class ZBackgroundTaskService(IZBackgroundTaskService, IZBackgroundTaskListener):

    def __init__(self):
        self.logger = None
        self.tasksDirectory = None
        self.tasks = []
        self.listeners = ZListenerSet()
    # end __init__()

    def _getTasksDirectory(self, applicationModel):
        return applicationModel.getUserProfile().getDirectory(u"bgtasks") #$NON-NLS-1$
    # end _getTasksDirectory()

    def addListener(self, listener):
        self.listeners.append(listener)
    # end addListener()

    def removeListener(self, listener):
        self.listeners.remove(listener)
    # end removeListener()

    def start(self, applicationModel):
        self.logger = applicationModel.getEngine().getService(IZAppServiceIDs.LOGGER_SERVICE_ID)
        self.tasksDirectory = self._getTasksDirectory(applicationModel)
        self.tasks = self._loadTasks()
        self.logger.debug(u"Background Task Service started [%d tasks loaded]." % len(self.tasks)) #$NON-NLS-1$
    # end start()

    def stop(self):
        # First, stop all tasks.
        for task in self.tasks:
            if task.isRunning():
                task.stop()

        self.tasks = []
    # end stop()

    def getTasks(self):
        return self.tasks
    # end getTasks()

    def getTask(self, taskId):
        for task in self.tasks:
            if task.getId() == taskId:
                return task
        return None
    # end getTask()

    def addTask(self, task):
        task.setId(generate())
        taskLogFilename = os.path.join(self.tasksDirectory, task.getId() + u".task.log") #$NON-NLS-1$
        task.setLogLocation(taskLogFilename)
        self.tasks.append(task)

        self.listeners.doCallback(u"onTaskAdded", [task]) #$NON-NLS-1$
        self._resumeTask(task)

        # Wait until the num work units has been set by the task (but only
        # wait for up to 30 seconds).
        numWaits = 0
        while task.getNumWorkUnits() <= 0 and numWaits < 60:
            time.sleep(0.5)
            numWaits = numWaits + 1
        if task.getNumWorkUnits() <= 0:
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.TaskFailedToStartError") % task.getName()) #$NON-NLS-1$
    # end addTask()

    def cancelTask(self, taskId, removeFlag = False):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToCancelDoesNotExist") % taskId) #$NON-NLS-1$
        task.cancel()
        task.detachListener(self)
        self.listeners.doCallback(u"onTaskCancelled", [task]) #$NON-NLS-1$
        if removeFlag:
            self.removeTask(taskId)
    # end cancelTask()

    def removeTask(self, taskId):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToRemoveDoesNotExist") % taskId) #$NON-NLS-1$
        if task.isRunning():
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToRemoveStillRunning") % taskId) #$NON-NLS-1$
        self.tasks.remove(task)

        self._removeTask(task)

        self.listeners.doCallback(u"onTaskRemoved", [task]) #$NON-NLS-1$
    # end removeTask()

    def resumeTask(self, taskId, listener = None):
        task = self.getTask(taskId)
        if task is None:
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToResumeTaskNotFound") % taskId) #$NON-NLS-1$
        if task.isRunning():
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToResumeTaskAlreadyRunning") % taskId) #$NON-NLS-1$
        if task.isComplete():
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToResumeTaskComplete") % taskId) #$NON-NLS-1$
        if not task.isResumable():
            raise ZAppFrameworkException(_extstr(u"backgroundtaskimpl.FailedToResumeTaskNotResumable") % taskId) #$NON-NLS-1$
        if listener is not None:
            task.attachListener(listener)
        self._resumeTask(task)

        self.listeners.doCallback(u"onTaskResumed", [task]) #$NON-NLS-1$

        return task
    # end resumeTask()

    def _loadTasks(self):
        tasks = []

        taskFiles = getDirectoryListing(self.tasksDirectory, TASK_FILE_FILTER)
        for taskFile in taskFiles:
            try:
                task = self._loadTask(taskFile)
                # Restart any resumable (but not cancelled) tasks.
                if task.isResumable() and not task.isCancelled() and not task.isComplete() and not task.hasError():
                    self._resumeTask(task)
                tasks.append(task)
            except Exception, e:
                self.logger.exception(e)

        return tasks