diva.sketch

Class MultiStateInterpreter

java.lang.Object

diva.canvas.interactor.AbstractInteractor

diva.sketch.BasicInterpreter

diva.sketch.MultiStateInterpreter

All Implemented Interfaces:

LayerListener, LayerMotionListener, Interactor, EventListener

Direct Known Subclasses:

CommandInterpreter, WhiteboardView.SketchInterpreter

public class MultiStateInterpreter
extends BasicInterpreter

A MultiStateInterpreter inherits from BasicInterpreter. It implements a FSM (finite state machine) in order to keep track of mouse states, for example, whether or not the mouse has been hold down in place for a while (hold listeners), how many clicks have been registered so far (click listeners), or it's simply a drawing event (stroke listeners). Different listeners can be added to receive different notification from the interpreter. For instance, a click listener will be notified only when mouse clicks happen whereas a hold listener will be notified only when the mouse has been hold for a while.

Version:

$Revision: 1.3 $

Author:

Michael Shilman (michaels@eecs.berkeley.edu), Heloise (hwawen@eecs.berkeley.edu)

Field Summary

Fields

Modifier and Type	Field and Description
static int	CLICK_TIMEOUT The timeout for single/double/triple/..
static int	HOLD_TIMEOUT The timeout for the popup hold, in milliseconds.
static int	MIN_DRAG_DISTANCE The distance beyond which a click becomes a drag.

Fields inherited from class diva.sketch.BasicInterpreter

_controller, _curStroke, _curSymbol, _strokeBuffer

Constructor Summary

Constructors

Constructor and Description
MultiStateInterpreter(SketchController c) Create a BasicInterpreter which is used by the specified controller to interpret sketch input.

Method Summary

Modifier and Type	Method and Description
void	addClickListener(Interactor l) Add a listener of clicks.
void	addHoldListener(Interactor l) Add a listener of hold invokations.
void	addStrokeListener(Interactor l) Add a stroke listener that gets mouse-down, mouse-moved, and mouse-released events for drawing strokes.
int	getClickCount()
void	mouseDragged(LayerEvent e) Consume the event so it doesn't get passed down to the layer below.
void	mousePressed(LayerEvent e) Consume the event so it doesn't get passed down to the * layer below.
void	mouseReleased(LayerEvent e) Consume the event.
void	removeClickListener(Interactor l) Removes a click listener that was added with addClickListener().
void	removeHoldListener(Interactor l) Removes a hold listener that was added with addHoldListener().
void	removeStrokeListener(Interactor l) Removes a stroke listener that was added with addStrokeListener().
void	timeout() Respond to the mouse released event.

Methods inherited from class diva.sketch.BasicInterpreter

appendStroke, finishStroke, getController, getCurrentStroke, getCurrentSymbol, isMotionEnabled, mouseEntered, mouseExited, mouseMoved, removeCurrentSymbol, startStroke

Methods inherited from class diva.canvas.interactor.AbstractInteractor

accept, getMouseFilter, isConsuming, isEnabled, mouseClicked, setConsuming, setEnabled, setMotionEnabled, setMouseFilter

Methods inherited from class java.lang.Object

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

Field Detail

MIN_DRAG_DISTANCE

public static final int MIN_DRAG_DISTANCE

The distance beyond which a click becomes a drag.

See Also:

Constant Field Values

HOLD_TIMEOUT

public static final int HOLD_TIMEOUT

The timeout for the popup hold, in milliseconds.

See Also:

Constant Field Values

CLICK_TIMEOUT

public static final int CLICK_TIMEOUT

The timeout for single/double/triple/.. clicks, in milliseconds.

See Also:

Constant Field Values

Constructor Detail

MultiStateInterpreter

public MultiStateInterpreter(SketchController c)

Create a BasicInterpreter which is used by the specified controller to interpret sketch input.

Method Detail

addClickListener

public void addClickListener(Interactor l)

Add a listener of clicks. This listener will get MOUSE_CLICKED events when the mouse is clicked one or more times. It will only get the largest number of clicks in a sequence. So, for example, if the user triple-clicks, the listener will only get a triple- click event and won't get a double-click event.

addHoldListener

public void addHoldListener(Interactor l)

Add a listener of hold invokations. This listener will get an action event when the user presses the mouse button and holds for the duration of HOLD_TIMEOUT.

addStrokeListener

public void addStrokeListener(Interactor l)

Add a stroke listener that gets mouse-down, mouse-moved, and mouse-released events for drawing strokes. The click-count of the mouse events allows the client to do multiple modes based on a single/double/etc. click before the stroke was drawn.

getClickCount

public int getClickCount()

mouseDragged

public void mouseDragged(LayerEvent e)

Consume the event so it doesn't get passed down to the layer below. If the previous event was a mouse press, check to see how far the cursor has moved. If the distance is >= MIN_DRAG_DISTANCE, send each stroke listener both a pressed event(_pressedEvent) and a dragged event (e). If the previous event was a mouse drag, send the event (e) to the stroke listeners.

Specified by:

mouseDragged in interface LayerListener

Overrides:

mouseDragged in class BasicInterpreter

mousePressed

public void mousePressed(LayerEvent e)

Consume the event so it doesn't get passed down to the * layer below. Start a Timer for HOLD_TIMEOUT amount of time.

Specified by:

mousePressed in interface LayerListener

Overrides:

mousePressed in class BasicInterpreter

mouseReleased

public void mouseReleased(LayerEvent e)

Consume the event. If the previous event was a mouse press, start a Timer for CLICK_TIMEOUT amount of time. If the previous event was a mouse drag, notify stroke listeners of this mouse released event (e).

Specified by:

mouseReleased in interface LayerListener

Overrides:

mouseReleased in class BasicInterpreter

timeout

public void timeout()

Respond to the mouse released event. This adjusts the state based on the current state and outputs an event if the mouse has been pressed and we are now dragging.

removeClickListener

public void removeClickListener(Interactor l)

Removes a click listener that was added with addClickListener().

See Also:

#addClickListener(MouseListener)

removeHoldListener

public void removeHoldListener(Interactor l)

Removes a hold listener that was added with addHoldListener().

See Also:

#addHoldListener(ActionListener)

removeStrokeListener

public void removeStrokeListener(Interactor l)

Removes a stroke listener that was added with addStrokeListener().

See Also:

#addStrokeListener(MouseInputListener)