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Class quicktime.app.actions.PeriodicAction

java.lang.Object
   |
   +----quicktime.app.actions.PeriodicAction

public abstract class PeriodicAction
extends Object
implements Ticklish

This class is the base class for all periodically recurring time based actions. The Actionable object (if defined) will be an object that has its trigger method called when the PeriodicAction sub-class action is executed or when a constraining condition of the action is reached. The action is tickled periodically and whether it will do its action is dependant upon the time interval as specified by the scale and period and the time and effective rate of the tickle call.

scale == 10, period = 1 => action executed 10 times a second at er == 1
scale == 2, period = 1 => action is executed 2 times a second at er == 1
scale == 1, scale = 2 => action is executed once every 2 seconds at er == 1

Every time the action is executed the time is kept and consequent calls to tickle result in a comparison between the new time, the rate and the last time the action was executed. Whether the action is executed is calculated by:
if (currentTime <= period / scale * 1000 / effectiveRate + lastTime) at rate > 0.
The tickle method is not called with an effectiveRate of 0. Whether the doAction method is called can also be affected by a flag that controls whether an action is triggered depending on rate settings.

actor: The actionable actor object that can be invoked by an action if a constraining condition is reached
reschedule: If true then the tickle method returns true and the action is considered to be still active by its owner and will be invoked on consequent tickles.

PeriodicAction(int, int): Create a PeriodicAction.

constraintReached(): If after the doAction method has exeucted this method returns true then if the Action has an Actionable object this actionable is triggered.
doAction(float, int): This method is called by the tickle method when an action becomes active.
equals(Object): Returns true if the objects are equal or false otherwise.
getActionable(): This method retreives the current actor that is attached to the action
getPeriod(): Returns the current period of the action
getScale(): Return the current scale of the action.
getTriggerCondition(): Returns the trigger condition of the action - an action can trigger either when rate is positive, rate is negative or either.
setActionable(Actionable): This method sets the actionable object of the action.
setPeriod(int): Sets the current period of the action - how many scale ticks will elapse before the action is executed.
setScale(int): Sets the scale of the action - this is the resolution of a second at rate == 1, thus a scale of 10 is 100msecs at rate == 1, 50msecs at rate == 2 etc.
setTriggerCondition(int): Sets the trigger condition of the action - an action can trigger either when rate is positive, rate is negative or either.
tickle(float, int): This method can be called as often as you like, though effective rate cannot be zero.
timeChanged(int): This method should be called by the actions owner whenver a time condition of the owner's time line has changed, as this can effect the trigger conditions of the action.
toString(): Return a String representation of this object.

actor

 protected Actionable actor

The actionable actor object that can be invoked by an action if a constraining condition is reached

reschedule

 protected boolean reschedule

If true then the tickle method returns true and the action is considered to be still active by its owner and will be invoked on consequent tickles.

PeriodicAction

 protected PeriodicAction(int scale,
                          int period)

Create a PeriodicAction. Subclasses are responsible for defining the action that occurs whenever the action is invoked.

Parameters:: scale - the amount with which a second is divided into at a rate of one; period - the number of scale ticks that elapse between invocations of the action.

timeChanged

 public void timeChanged(int newTime) throws QTException

This method should be called by the actions owner whenver a time condition of the owner's time line has changed, as this can effect the trigger conditions of the action.

Parameters:: the - new time expressed in Ticklish.kScale ticks
See Also:: Ticklish

tickle

 public boolean tickle(float effectiveRate,
                       int currentTime) throws QTException

This method can be called as often as you like, though effective rate cannot be zero. The provided time and rate values are used to calculate whether an action should be executed. If an action should be executed this method calls the doAction method which should perform the action.

Parameters:: er - the actual rate at which the action has been triggered; t - the time in Ticklish.kScale that the action has been triggered
Returns:: true if the action is still interested in being tickled.

doAction

 protected abstract void doAction(float er,
                                  int t) throws QTException

This method is called by the tickle method when an action becomes active. Subclasses should do their desired actions when this method is called.

Parameters:: er - the actual rate at which the action has been triggered; t - the time in Ticklish.kScale that the action has been triggered

constraintReached

 protected abstract boolean constraintReached()

If after the doAction method has exeucted this method returns true then if the Action has an Actionable object this actionable is triggered. If constraintReached returns false no further action is taken.

Returns:: true if the actionable object (if set) should be triggered

setActionable

 public void setActionable(Actionable actor)

This method sets the actionable object of the action.

getActionable

 public Actionable getActionable()

This method retreives the current actor that is attached to the action

setPeriod

 public void setPeriod(int period)

Sets the current period of the action - how many scale ticks will elapse before the action is executed. If the period is zero the doAction method is called whenever the PeriodicAction is tickled.

Parameters:: period - the new period

getPeriod

 public int getPeriod()

Returns the current period of the action

Returns:: the period

setScale

 public void setScale(int s)

Sets the scale of the action - this is the resolution of a second at rate == 1, thus a scale of 10 is 100msecs at rate == 1, 50msecs at rate == 2 etc. This value must be greater than zero.

Parameters:: s - the new scale or resolution of the action

getScale

 public int getScale()

Return the current scale of the action.

Returns:: the current scale

getTriggerCondition

 public int getTriggerCondition()

Returns the trigger condition of the action - an action can trigger either when rate is positive, rate is negative or either.

Returns:: the current trigger condition
See Also:: triggerTimeFwd, triggerTimeBwd, triggerTimeEither

setTriggerCondition

 public void setTriggerCondition(int cond)

Sets the trigger condition of the action - an action can trigger either when rate is positive, rate is negative or either.

Parameters:: cond - the current trigger condition
See Also:: triggerTimeFwd, triggerTimeBwd, triggerTimeEither

toString

 public String toString()

Return a String representation of this object.

Returns:: a String
Overrides:: toString in class Object

equals

 public boolean equals(Object obj)

Returns true if the objects are equal or false otherwise.

Parameters:: obj - the object to test
Returns:: a boolean
Overrides:: equals in class Object

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