Package diva.canvas.interactor

Class DragInteractor

java.lang.Object

diva.canvas.interactor.AbstractInteractor

diva.canvas.interactor.DragInteractor

All Implemented Interfaces:

LayerListener, LayerMotionListener, Interactor, java.util.EventListener

Direct Known Subclasses:

BoundedDragInteractor, ConnectorInteractor, NodeDragInteractor, SelectionDragger

public class DragInteractor
extends AbstractInteractor

An interactor that responds to mouse drag events. It adds the notion of constraints, so that dragging can be limited to certain coordinates or "snapped" to suitable locations, and a "target" array, which contain the figure or figures that are dragged.

Version:

$Id$

Author:

John Reekie

Constructor Summary

Constructors

Constructor	Description
DragInteractor()

Method Summary

Modifier and Type	Method	Description
void	addLayerListener(LayerListener l)	Add the given layer listener to this interactor.
void	appendConstraint(PointConstraint constraint)	Append a constraint to the list of constraints on this interactor.
void	constrainPoint(java.awt.geom.Point2D p)	Constrain a point using the current constraints.
void	fireLayerEvent(LayerEvent event)	Fire a layer event.
boolean	getSelectiveEnabled()	Get the flag that says that the interactor responds only if the figure being moused on is selected.
java.lang.Object[]	getTargetArray()	Get the target array.
double	getX()	Get the current value of the X coordinate.
double	getY()	Get the current value of the Y coordinate.
void	mouseDragged(LayerEvent e)	Constrain the point and move the target if the mouse move.
void	mousePressed(LayerEvent e)	Handle a mouse press on a figure or layer.
void	mouseReleased(LayerEvent e)	Handle a mouse released event.
void	prependConstraint(PointConstraint constraint)	Prepend a constraint to the list of constraints on this interactor.
void	removeLayerListener(LayerListener l)	Remove the given layer listener from this interactor.
boolean	setSelectiveEnabled(boolean s)	Set the flag that says that the interactor responds only if the figure being moused on is selected.
void	setTargetArray(java.lang.Object[] arr)	Set the target that the interactor operates on.
void	setup(LayerEvent e)	Initialize the interactor before a mouse-pressed event is processed.
java.util.Iterator	targets()	Get an iterator over the target figures.
void	translate(LayerEvent e, double x, double y)	Translate the target by the given distance.

Methods inherited from class diva.canvas.interactor.AbstractInteractor

accept, getMouseFilter, isConsuming, isEnabled, isMotionEnabled, mouseClicked, mouseEntered, mouseExited, mouseMoved, setConsuming, setEnabled, setMotionEnabled, setMouseFilter

Methods inherited from class java.lang.Object

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

Constructor Detail

DragInteractor

public DragInteractor()

Method Detail

addLayerListener

public void addLayerListener(LayerListener l)

Add the given layer listener to this interactor. Any event that is received by this interactor will be passed on to the listener after it is handled by this interactor.

Parameters:

l - The listener

appendConstraint

public void appendConstraint(PointConstraint constraint)

Append a constraint to the list of constraints on this interactor.

Parameters:

constraint - The constraint.

constrainPoint

public void constrainPoint(java.awt.geom.Point2D p)

Constrain a point using the current constraints. The given point will be modified according to the current constraints. This method does not trigger constraint events. The caller must be careful to make a copy of the passed point if it is not guaranteed that changing the point will not affect other objects with a reference to it.

Parameters:

p - The point

fireLayerEvent

public void fireLayerEvent(LayerEvent event)

Fire a layer event.

Parameters:

event - The event

getSelectiveEnabled

public boolean getSelectiveEnabled()

Get the flag that says that the interactor responds only if the figure being moused on is selected. By default, this flag is false.

Returns:

True if selective is enabled.

See Also:

setSelectiveEnabled(boolean)

getTargetArray

public java.lang.Object[] getTargetArray()

Get the target array.

Returns:

the target array

See Also:

setTargetArray(Object[])

getX

public double getX()

Get the current value of the X coordinate.

Returns:

The x value

getY

public double getY()

Get the current value of the Y coordinate.

Returns:

the y value

mouseDragged

public void mouseDragged(LayerEvent e)

Constrain the point and move the target if the mouse move. The target movement is done by the translate() method, which can be overridden to change the behaviour. Nothing happens if the interactor is not enabled, or if it is "selective enabled" but not in the selection.

Specified by:

mouseDragged in interface LayerListener

Overrides:

mouseDragged in class AbstractInteractor

Parameters:

e - the event

mousePressed

public void mousePressed(LayerEvent e)

Handle a mouse press on a figure or layer. Set the target to be the figure contained in the event. Call the setup() method in case there is additional setup to do, then constrain the point and remember it. Nothing happens if the interactor is not enabled, or if it is "selective enabled" but not in the selection.

Specified by:

mousePressed in interface LayerListener

Overrides:

mousePressed in class AbstractInteractor

Parameters:

e - the event

mouseReleased

public void mouseReleased(LayerEvent e)

Handle a mouse released event. Nothing happens if the interactor is not enabled, if if it is "selective enabled" but not in the selection.

Specified by:

mouseReleased in interface LayerListener

Overrides:

mouseReleased in class AbstractInteractor

Parameters:

e - The event

prependConstraint

public void prependConstraint(PointConstraint constraint)

Prepend a constraint to the list of constraints on this interactor.

Parameters:

constraint - The constraint

removeLayerListener

public void removeLayerListener(LayerListener l)

Remove the given layer listener from this interactor.

Parameters:

l - the listener

setSelectiveEnabled

public boolean setSelectiveEnabled(boolean s)

Set the flag that says that the interactor responds only if the figure being moused on is selected. By default, this flag is false; if set true, then the mouse methods check that the figure is contained in the selection model of that figure's selection interactor (if it has one).

Parameters:

s - The value of selective enable

Returns:

The value of the selective enabled flag

See Also:

getSelectiveEnabled()

setTargetArray

public void setTargetArray(java.lang.Object[] arr)

Set the target that the interactor operates on. By default, this will be the figure obtained from the event, but this method can be used to set it to something else.

Parameters:

arr - The array

See Also:

getTargetArray()

setup

public void setup(LayerEvent e)

Initialize the interactor before a mouse-pressed event is processed. This default implementation does nothing, but clients can override to cause it to perform some action, such as setting up constraints.

Parameters:

e - The event

targets

public java.util.Iterator targets()

Get an iterator over the target figures.

Returns:

An iterator

translate

public void translate(LayerEvent e,
                      double x,
                      double y)

Translate the target by the given distance. The first argument is the figure that was moused one. Any overriding methods should be aware that the interactor may in general be operating on multiple figures, and use the targets() method to get them.

Parameters:

e - The event

x - the x distance

y - the y distance