com.gurock.smartinspect.scheduler

Class Scheduler

java.lang.Object

com.gurock.smartinspect.scheduler.Scheduler

public class Scheduler
extends Object

Responsible for scheduling protocol operations and executing them asynchronously in a different thread of control.

This class is used by the asynchronous protocol mode to asynchronously execute protocol operations. New commands can be scheduled for execution with the schedule method. The scheduler can be started and stopped with the start and stop methods. The scheduler uses a size limited queue to buffer scheduler commands. The maximum size of this queue can be set with the setThreshold method. To influence the behavior of the scheduler if new commands are enqueued and the queue is currently considered full, you can specify the throttle mode.

This class is guaranteed to be threadsafe.

Field Summary

Fields

Modifier and Type	Field and Description
static Logger	logger

Constructor Summary

Constructors

Constructor and Description
Scheduler(Protocol protocol) Creates and initializes a new Scheduler instance.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all scheduler commands from this scheduler.
long	getThreshold() Returns the maximum size of the scheduler command queue.
boolean	getThrottle() Indicates if the scheduler should automatically throttle threads that enqueue new scheduler commands.
boolean	schedule(SchedulerCommand command, SchedulerQueue.QueueEnd insertTo) Schedules a new command for asynchronous execution.
void	setThreshold(long threshold) Sets the maximum size of the scheduler command queue.
void	setThrottle(boolean throttle) Specifies if the scheduler should automatically throttle threads that enqueue new scheduler commands.
void	start() Starts this scheduler and the internal scheduler thread.
void	stop() Stops this scheduler and the internal scheduler thread.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

public static final Logger logger

Constructor Detail

Scheduler

public Scheduler(Protocol protocol)

Creates and initializes a new Scheduler instance.

Parameters:

protocol - The protocol on which to execute the actual operations like connect, disconnect, write or dispatch

Method Detail

start

public void start()

Starts this scheduler and the internal scheduler thread.

This method must be called before scheduling new commands with the schedule method. Call stop to stop the internal thread when the scheduler is no longer needed. Note that this method starts the internal scheduler thread only once. This means that subsequent calls to this method have no effect.

stop

public void stop()

Stops this scheduler and the internal scheduler thread.

This is the matching method for start. After calling this method, new commands will no longer be accepted by schedule and are ignored. This method blocks until the internal thread has processed the current content of the queue. Call clear before calling stop to exit the internal thread as soon as possible.

getThreshold

public long getThreshold()

Returns the maximum size of the scheduler command queue.

To influence the behavior of the scheduler if new commands are enqueued and the queue is currently considered full, you can specify the throttle mode.

Returns:

The maximum size of the scheduler command queue

setThreshold

public void setThreshold(long threshold)

Sets the maximum size of the scheduler command queue.

To influence the behavior of the scheduler if new commands are enqueued and the queue is currently considered full, you can specify the throttle mode.

Parameters:

threshold - The new maximum size of the scheduler command queue

getThrottle

public boolean getThrottle()

Indicates if the scheduler should automatically throttle threads that enqueue new scheduler commands.

If this method returns true and the queue is considered full when enqueuing new commands, the enqueuing thread is automatically throttled until there is room in the queue for the new command. In non-throttle mode, the thread is not blocked but older commands are removed from the queue.

Returns:

True if the scheduler should automatically throttle threads that enqueue new scheduler commands and false otherwise

setThrottle

public void setThrottle(boolean throttle)

Specifies if the scheduler should automatically throttle threads that enqueue new scheduler commands.

If this method is passed true and the queue is considered full when enqueuing new commands, the enqueuing thread is automatically throttled until there is room in the queue for the new command. In non-throttle mode, the thread is not blocked but older commands are removed from the queue.

Parameters:

throttle - Pass true if the scheduler should automatically throttle threads that enqueue new scheduler commands and false otherwise

schedule

public boolean schedule(SchedulerCommand command,
                        SchedulerQueue.QueueEnd insertTo)

Schedules a new command for asynchronous execution. This method adds the passed command to the internal queue of scheduler commands. The command is eventually executed by the internal scheduler thread. This method can block the caller if the scheduler operates in throttle mode and the internal queue is currently considered full (see setThreshold(long)).

Parameters:

command - The command to schedule

insertTo - End of a queue to insert a command to

Returns:

True if the command could be scheduled for asynchronous execution and false otherwise

clear

public void clear()

Removes all scheduler commands from this scheduler. This method clears the current queue of scheduler commands. If the stop method is called after calling clear and no new commands are stored between these two calls, the internal scheduler thread will exit as soon as possible (after the current command, if any, has been processed).