com.artemis.systems

Class DelayedIteratingSystem

java.lang.Object

com.artemis.BaseSystem

com.artemis.BaseEntitySystem

com.artemis.systems.DelayedIteratingSystem

All Implemented Interfaces:

EntitySubscription.SubscriptionListener

public abstract class DelayedIteratingSystem
extends BaseEntitySystem

Tracks cooldown per entity, processing entity when its timer runs out.

An example system would be an ExpirationSystem, that deletes entities after a certain lifetime. Instead of running a system that decrements a timeLeft value for each entity, you can simply use this system to execute in a future at a time of the shortest lived entity, and then reset the system to run at a time in a future at a time of the shortest lived entity, etc.

Another example system would be an AnimationSystem. You know when you have to animate a certain entity, e.g. in 300 milliseconds. So you can set the system to run in 300 ms to perform the animation.

This will save CPU cycles in some scenarios.

Implementation notes:
Within processExpired(Entity e) you must call offerDelay(float delay) if the entity's delay time is renewed. That method is also called by inserted(int entityId) for each newly matched entity.

Author:

Arni Arent

Field Summary

Fields inherited from class com.artemis.BaseEntitySystem

subscription

Fields inherited from class com.artemis.BaseSystem

world

Constructor Summary

Constructors

Constructor and Description
DelayedIteratingSystem()
DelayedIteratingSystem(Aspect.Builder aspect) Creates a new DelayedEntityProcessingSystem.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkProcessing() Does the system desire processing.
float	getInitialTimeDelay() Get the initial delay that the system was ordered to process entities after.
protected abstract float	getRemainingDelay(int entityId) Return the delay until this entity should be processed.
float	getRemainingTimeUntilProcessing() Get the time until the system is scheduled to run at.
protected float	getTimeDelta() Overridable method to provide custom time delta.
protected void	inserted(int entityId) Called if entity has come into scope for this system, e.g created or a component was added to it.
boolean	isRunning() Check if the system is counting down towards processing.
void	offerDelay(float offeredDelay) Restarts the system only if the delay offered is shorter than the time that the system is currently scheduled to execute at.
protected abstract void	processDelta(int entityId, float accumulatedDelta) Process an entity this system is interested in.
protected abstract void	processExpired(int entityId)
protected void	processSystem() Process the system.
void	stop() Stops the system from running, aborts current countdown.

Methods inherited from class com.artemis.BaseEntitySystem

getEntityIds, getSubscription, inserted, removed, removed, setWorld

Methods inherited from class com.artemis.BaseSystem

begin, dispose, end, getWorld, initialize, isEnabled, process, setEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

DelayedIteratingSystem

public DelayedIteratingSystem(Aspect.Builder aspect)

Creates a new DelayedEntityProcessingSystem.

Parameters:

aspect - the aspect to match against entities

DelayedIteratingSystem

public DelayedIteratingSystem()

Method Detail

processSystem

protected final void processSystem()

Description copied from class: BaseSystem

Process the system.

Specified by:

processSystem in class BaseSystem

inserted

protected void inserted(int entityId)

Description copied from class: BaseEntitySystem

Called if entity has come into scope for this system, e.g created or a component was added to it. Triggers right after any system finishes processing. Adding and immediately removing a component does not count as a permanently change and will prevent this method from being called. Not triggered for entities that have been destroyed immediately after being created (within a system).

Overrides:

inserted in class BaseEntitySystem

Parameters:

entityId - the entity that was added to this system

getRemainingDelay

protected abstract float getRemainingDelay(int entityId)

Return the delay until this entity should be processed.

Parameters:

entityId - entity

Returns:

delay

checkProcessing

protected final boolean checkProcessing()

Description copied from class: BaseSystem

Does the system desire processing. Useful when the system is enabled, but only occasionally needs to process. This only affects processing, and does not affect events or subscription lists.

Overrides:

checkProcessing in class BaseSystem

Returns:

true if the system should be processed, false if not.

See Also:

both must be true before the system will process.

getTimeDelta

protected float getTimeDelta()

Overridable method to provide custom time delta.

processDelta

protected abstract void processDelta(int entityId,
                                     float accumulatedDelta)

Process an entity this system is interested in.

Substract the accumulatedDelta from the entities defined delay.

Parameters:

entityId - the entity to process

accumulatedDelta - the delta time since this system was last executed

processExpired

protected abstract void processExpired(int entityId)

offerDelay

public void offerDelay(float offeredDelay)

Restarts the system only if the delay offered is shorter than the time that the system is currently scheduled to execute at.

If the system is already stopped (not running) then the offered delay will be used to restart the system with no matter its value.

If the system is already counting down, and the offered delay is larger than the time remaining, the system will ignore it. If the offered delay is shorter than the time remaining, the system will restart itself to run at the offered delay.

Parameters:

offeredDelay - delay to offer

getInitialTimeDelay

public float getInitialTimeDelay()

Get the initial delay that the system was ordered to process entities after.

Returns:

the originally set delay

getRemainingTimeUntilProcessing

public float getRemainingTimeUntilProcessing()

Get the time until the system is scheduled to run at.

Returns zero (0) if the system is not running. Use isRunning() before checking this value.

Returns:

time when system will run at

isRunning

public boolean isRunning()

Check if the system is counting down towards processing.

Returns:

true if it's counting down, false if it's not running

stop

public void stop()

Stops the system from running, aborts current countdown.

Call offerDelay or restart to run it again.