org.dishevelled.piccolo.sprite.statemachine

Class AbstractStateMachineSprite

java.lang.Object

org.piccolo2d.PNode

org.dishevelled.piccolo.sprite.statemachine.AbstractStateMachineSprite

All Implemented Interfaces:

Printable, Serializable, Cloneable

public abstract class AbstractStateMachineSprite
extends org.piccolo2d.PNode

Abstract Piccolo2D state machine sprite node.

This abstract sprite node utilizes a state machine to manage all its state transitions. Consider the following simple state machine in State Chart XML (SCXML) format:

 <scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0" initialstate="normal">
   <state id="normal">
     <transition event="walk" target="walking"/>
   </state>
   <state id="walking">
     <transition event="stop" target="normal"/>
   </state>
 </scxml>
 

Subclasses may provide state transition methods that fire an event to the underlying state machine.

 public void walk() {
   fireStateMachineEvent("walk");
 }
 public void stop() {
   fireStateMachineEvent("stop");
 }
 

Subclasses may associate visual properties and behavior with states by providing private no-arg state methods which will be called via reflection on entry by the state machine engine.

 private void normal() {
   walkingActivity.stop();
 }
 private void walking() {
   walkingActivity.start();
 }
 

Animations can be associated with states by implementing the protected createAnimation method. Create and return an animation for the specified state id, or return null if no such animation exists.

   protected Animation createAnimation(final String id) {
     Image image = loadImage(getClass(), id + ".png");
     return Animations.createAnimation(image);
   }
 

Altogether, the typical implementation pattern for a subclass of this abstract sprite node looks like

 class MySprite extends AbstractStateMachineSprite {
   // walking activity
   private final WalkingActivity walkingActivity = ...;
   // load the state machine backing all instances of this MySprite
   private static final SCXML STATE_MACHINE = loadStateMachine(MySprite.class, "stateMachine.xml");

   MySprite() {
     super();
     // initialize the state machine
     initializeStateMachine(STATE_MACHINE);
     // sprites have no bounds by default
     setWidth(14.0d);
     setHeight(24.0d);
   }

   protected Animation createAnimation(final String id) {
     // load a single PNG image for each state id
     Image image = loadImage(getClass(), id + ".png");
     return Animations.createAnimation(image);
   }

   // methods to fire state transition events
   public void walk() {
     fireStateMachineEvent("walk");
   }
   public void stop() {
     fireStateMachineEvent("stop");
   }

   // methods that receive notification of state transitions
   private void normal() {
     walkingActivity.stop();
   }
   private void walking() {
     walkingActivity.start();
   }
 }
 

Version:

$Revision$ $Date$

Author:

Michael Heuer

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.piccolo2d.PNode

org.piccolo2d.PNode.PSceneGraphDelegate

Field Summary

Fields inherited from class org.piccolo2d.PNode

FILL_STRATEGY_ASPECT_COVER, FILL_STRATEGY_ASPECT_FIT, FILL_STRATEGY_EXACT_FIT, PROPERTY_BOUNDS, PROPERTY_CHILDREN, PROPERTY_CHILDREN_PICKABLE, PROPERTY_CLIENT_PROPERTIES, PROPERTY_CODE_BOUNDS, PROPERTY_CODE_CHILDREN, PROPERTY_CODE_CHILDREN_PICKABLE, PROPERTY_CODE_CLIENT_PROPERTIES, PROPERTY_CODE_FULL_BOUNDS, PROPERTY_CODE_PAINT, PROPERTY_CODE_PARENT, PROPERTY_CODE_PICKABLE, PROPERTY_CODE_TRANSFORM, PROPERTY_CODE_TRANSPARENCY, PROPERTY_CODE_VISIBLE, PROPERTY_FULL_BOUNDS, PROPERTY_PAINT, PROPERTY_PARENT, PROPERTY_PICKABLE, PROPERTY_TRANSFORM, PROPERTY_TRANSPARENCY, PROPERTY_VISIBLE, SCENE_GRAPH_DELEGATE

Fields inherited from interface java.awt.print.Printable

NO_SUCH_PAGE, PAGE_EXISTS

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractStateMachineSprite() Create a new abstract state machine sprite node.

Method Summary

Methods

Modifier and Type	Method and Description
void	advance() Advance this state machine sprite node one frame.
protected abstract Animation	createAnimation(String id) Create and return an animation for the specified state id, if any.
protected void	fireStateMachineEvent(String eventName) Fire a state machine event with the specified event name.
protected Animation	getCurrentAnimation() Return the current animation for this state machine sprite.
protected int	getFrameSkip() Return the number of frames to skip.
protected void	initializeStateMachine(SCXML stateMachine) Initialize the specified state machine.
protected static <T> BufferedImage	loadImage(Class<T> cls, String name) Load the image resource with the specified name, if any.
protected static <T> SCXML	loadStateMachine(Class<T> cls, String name) Load the state machine resource with the specified name, if any.
void	paint(org.piccolo2d.util.PPaintContext paintContext)
protected void	resetStateMachine() Reset the state machine to its "initial" configuration.
protected void	setFrameSkip(int frameSkip) Set the number of frames to skip to frameSkip.

Methods inherited from class org.piccolo2d.PNode

addActivity, addAttribute, addChild, addChild, addChildren, addInputEventListener, addPropertyChangeListener, addPropertyChangeListener, animateToBounds, animateToColor, animateToPositionScaleRotation, animateToRelativePosition, animateToTransform, animateToTransparency, animateTransformToBounds, centerBoundsOnPoint, centerFullBoundsOnPoint, clone, computeFullBounds, endResizeBounds, findIntersectingNodes, fireChildPropertyChange, firePropertyChange, fullIntersects, fullPaint, fullPick, getAllNodes, getAllNodes, getAttribute, getAttribute, getBooleanAttribute, getBounds, getBoundsChanged, getBoundsReference, getBoundsVolatile, getChild, getChildBoundsInvalid, getChildBoundsVolatile, getChildPaintInvalid, getChildrenCount, getChildrenIterator, getChildrenPickable, getChildrenReference, getClientProperties, getClientPropertyKeysEnumeration, getDoubleAttribute, getFullBounds, getFullBoundsInvalid, getFullBoundsReference, getGlobalBounds, getGlobalFullBounds, getGlobalRotation, getGlobalScale, getGlobalToLocalTransform, getGlobalTranslation, getHeight, getInputEventListeners, getIntegerAttribute, getInverseTransform, getListenerList, getLocalToGlobalTransform, getName, getOccluded, getOffset, getPaint, getPaintInvalid, getParent, getPickable, getPropertyChangeParentMask, getRoot, getRotation, getScale, getTransform, getTransformReference, getTransparency, getUnionOfChildrenBounds, getVisible, getWidth, getX, getXOffset, getY, getYOffset, globalToLocal, globalToLocal, globalToLocal, indexOfChild, internalUpdateBounds, intersects, invalidateFullBounds, invalidateLayout, invalidatePaint, isAncestorOf, isDescendentOf, isDescendentOfRoot, isOpaque, layoutChildren, lerp, localToGlobal, localToGlobal, localToGlobal, localToParent, localToParent, localToParent, lower, lower, lowerBelow, lowerToBottom, lowerToBottom, offset, paintAfterChildren, parentBoundsChanged, parentToLocal, parentToLocal, parentToLocal, pick, pickAfterChildren, print, print, raise, raise, raiseAbove, raiseToTop, raiseToTop, removeAllChildren, removeChild, removeChild, removeChildren, removeFromParent, removeInputEventListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaintFrom, reparent, replaceWith, resetBounds, rotate, rotateAboutPoint, rotateAboutPoint, rotateInPlace, scale, scaleAboutPoint, scaleAboutPoint, setBounds, setBounds, setBoundsChanged, setChildBoundsInvalid, setChildBoundsVolatile, setChildPaintInvalid, setChildrenPickable, setFullBoundsInvalid, setGlobalRotation, setGlobalScale, setGlobalTranslation, setHeight, setName, setOccluded, setOffset, setOffset, setPaint, setPaintInvalid, setParent, setPickable, setPropertyChangeParentMask, setRotation, setScale, setTransform, setTransparency, setVisible, setWidth, setX, setY, signalBoundsChanged, startResizeBounds, toImage, toImage, toImage, toImage, transformBy, translate, validateFullBounds, validateFullPaint

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractStateMachineSprite

protected AbstractStateMachineSprite()

Create a new abstract state machine sprite node.

Method Detail

createAnimation

protected abstract Animation createAnimation(String id)

Create and return an animation for the specified state id, if any.

Parameters:

id - state id

Returns:

an animation for the specified state id, or null if no such animation exists

initializeStateMachine

protected final void initializeStateMachine(SCXML stateMachine)

Initialize the specified state machine. Animations are loaded for all the state ids and the current animation is set to the initial target, if any.

Note: this method should be called from the constructor of a subclass after its state machine has been instantiated.

Parameters:

stateMachine - state machine to initialize, must not be null

resetStateMachine

protected final void resetStateMachine()

Reset the state machine to its "initial" configuration.

fireStateMachineEvent

protected final void fireStateMachineEvent(String eventName)

Fire a state machine event with the specified event name.

Parameters:

eventName - event name, must not be null

getFrameSkip

protected final int getFrameSkip()

Return the number of frames to skip. Defaults to 0.

Returns:

the number of frames to skip

setFrameSkip

protected final void setFrameSkip(int frameSkip)

Set the number of frames to skip to frameSkip.

Parameters:

frameSkip - number of frames to skip, must be >= 0

getCurrentAnimation

protected final Animation getCurrentAnimation()

Return the current animation for this state machine sprite.

Returns:

the current animation for this state machine sprite

advance

public final void advance()

Advance this state machine sprite node one frame.

paint

public final void paint(org.piccolo2d.util.PPaintContext paintContext)

Overrides:

paint in class org.piccolo2d.PNode

loadStateMachine

protected static final <T> SCXML loadStateMachine(Class<T> cls,
                         String name)

Load the state machine resource with the specified name, if any. Any exceptions thrown will be ignored.

Parameters:

cls - class

name - name

Returns:

the state machine resource with the specified name, or null if no such resource exists

loadImage

protected static final <T> BufferedImage loadImage(Class<T> cls,
                          String name)

Load the image resource with the specified name, if any. Any exceptions thrown will be ignored.

Parameters:

cls - class

name - name

Returns:

the image resource with the specified name, or null if no such resource exists