Handle

All Superinterfaces:

java.util.EventListener, java.awt.event.KeyListener

All Known Implementing Classes:

AbstractConnectionHandle, AbstractHandle, AbstractRotateHandle, BezierControlPointHandle, BezierNodeHandle, BezierOutlineHandle, BezierScaleHandle, BoundsOutlineHandle, CloseHandle, ConnectionEndHandle, ConnectionStartHandle, ConnectorHandle, ConvexHullOutlineHandle, DragHandle, FontSizeHandle, LinkHandle, LocatorHandle, MoveHandle, NullHandle, ODGPathOutlineHandle, ODGRectRadiusHandle, OrientationHandle, RotateHandle, RoundRectangleRadiusHandle, SVGPathOutlineHandle, SVGRectRadiusHandle, TextOverflowHandle
```
public interface Handle
extends java.awt.event.KeyListener
```
A handle is used to change one aspect of a Figure by direct manipulation.
A handle is owned by a figure and associated to a DrawingView. Handle knows its owning figure and its associated drawing view.
Handles are drawn using the view coordinates of the associated DrawingView. Handle uses methods of the drawing view to translate the view coordinates into drawing coordinates, which is the coordinate system used by the owning figure.
Mouse and keyboard events of the user occur on a drawing view, and are preprocessed by the DragTracker of a SelectionTool. DragTracker invokes "track" methods on the handle, such as trackStart, trackStep and trackEnd.
Handle forwards UndoableEdit events to the drawing object onto which it is performing changes.
Design Patterns
Framework
The following interfaces define the contracts of a framework for structured drawing editors:
Contract: Drawing, Figure, DrawingView, DrawingEditor, Handle and Tool.
Observer
State changes of handles can be observed by other objects. Specifically DrawingView observes area invalidations and remove requests of handles.
Subject: Handle; Observer: HandleListener; Event: HandleEvent; Concrete Observer: DrawingView.
Chain of responsibility
Mouse and keyboard events of the user occur on the drawing view, and are preprocessed by the DragTracker of a SelectionTool. In turn DragTracker invokes "track" methods on a Handle which in turn changes an aspect of a figure.
Client: SelectionTool; Handler: DragTracker, Handle.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`addHandleListener(HandleListener l)` Adds a listener for this handle.
`boolean`	`contains(java.awt.Point p)` Tests if a point is contained in the handle.
`java.util.Collection<Handle>`	`createSecondaryHandles()` Creates secondary handles.
`void`	`dispose()` Disposes the resources aquired by the handler.
`void`	`draw(java.awt.Graphics2D g)` Draws this handle.
`java.awt.Rectangle`	`getBounds()` Returns the bounding box of the handle.
`java.awt.Cursor`	`getCursor()` Returns a cursor for the handle.
`java.awt.Rectangle`	`getDrawingArea()` Returns the drawing area of the handle.
`Figure`	`getOwner()` Returns the owner of this handle.
`java.lang.String`	`getToolTipText(java.awt.Point p)` Returns a tooltip for the specified location.
`void`	`invalidate()` Invalidates the handle.
`boolean`	`isCombinableWith(Handle handle)` Returns true, if this handle is combinable with the specified handle.
`void`	`removeHandleListener(HandleListener l)` Removes a listener for this handle.
`void`	`setView(DrawingView view)` Sets the view of the handle.
`void`	`trackDoubleClick(java.awt.Point p, int modifiersEx)` Tracks a double click.
`void`	`trackEnd(java.awt.Point anchor, java.awt.Point lead, int modifiersEx)` Tracks the end of the interaction.
`void`	`trackStart(java.awt.Point anchor, int modifiersEx)` Tracks the start of the interaction.
`void`	`trackStep(java.awt.Point anchor, java.awt.Point lead, int modifiersEx)` Tracks a step of the interaction.
`void`	`viewTransformChanged()` This method is invoked by the drawing view, when its transform has changed.

Methods inherited from interface java.awt.event.KeyListener
keyPressed, keyReleased, keyTyped

- Method Detail
  - getOwner
```
Figure getOwner()
```
    Returns the owner of this handle.
  - setView
```
void setView(DrawingView view)
```
    Sets the view of the handle.
  - addHandleListener
```
void addHandleListener(HandleListener l)
```
    Adds a listener for this handle.
  - removeHandleListener
```
void removeHandleListener(HandleListener l)
```
    Removes a listener for this handle.
  - getBounds
```
java.awt.Rectangle getBounds()
```
    Returns the bounding box of the handle. Note: The bounding box must be returned in the coordinate system of the DrawingView.
  - getDrawingArea
```
java.awt.Rectangle getDrawingArea()
```
    Returns the drawing area of the handle. Note: The drawing area must be returned in the coordinate system of the DrawingView.
  - contains
```
boolean contains(java.awt.Point p)
```
    Tests if a point is contained in the handle.
  - draw
```
void draw(java.awt.Graphics2D g)
```
    Draws this handle. Note: The handle is drawn with the coordinate system of the DrawingView.
  - invalidate
```
void invalidate()
```
    Invalidates the handle. This method informs its listeners that its current display box is invalid and should be refreshed.
  - dispose
```
void dispose()
```
    Disposes the resources aquired by the handler.
  - getCursor
```
java.awt.Cursor getCursor()
```
    Returns a cursor for the handle.
  - isCombinableWith
```
boolean isCombinableWith(Handle handle)
```
    Returns true, if this handle is combinable with the specified handle. This method is used to determine, if multiple handles need to be tracked, when more than one figure is selected.
  - trackStart
```
void trackStart(java.awt.Point anchor,
                int modifiersEx)
```
    Tracks the start of the interaction. The default implementation does nothing.
    
    Parameters:
    
    anchor - the position where the interaction started
  - trackStep
```
void trackStep(java.awt.Point anchor,
               java.awt.Point lead,
               int modifiersEx)
```
    Tracks a step of the interaction.
    
    Parameters:
    
    anchor - the position where the interaction started
    
    lead - the current position
  - trackEnd
```
void trackEnd(java.awt.Point anchor,
              java.awt.Point lead,
              int modifiersEx)
```
    Tracks the end of the interaction.
    
    Parameters:
    
    anchor - the position where the interaction started
    
    lead - the current position
  - trackDoubleClick
```
void trackDoubleClick(java.awt.Point p,
                      int modifiersEx)
```
    Tracks a double click.
  - viewTransformChanged
```
void viewTransformChanged()
```
    This method is invoked by the drawing view, when its transform has changed. This means, that DrawingView.viewToDrawing and DrawingView.drawingToView will return different values than they did before.
  - createSecondaryHandles
```
java.util.Collection<Handle> createSecondaryHandles()
```
    Creates secondary handles.
  - getToolTipText
```
java.lang.String getToolTipText(java.awt.Point p)
```
    Returns a tooltip for the specified location.

Interface Handle

Method Summary

Methods inherited from interface java.awt.event.KeyListener

Method Detail

getOwner

setView

addHandleListener

removeHandleListener

getBounds

getDrawingArea

contains

draw

invalidate

dispose

getCursor

isCombinableWith

trackStart

trackStep

trackEnd

trackDoubleClick

viewTransformChanged

createSecondaryHandles

getToolTipText