/*
Copyright (c) 1998-2006 The Regents of the University of California
All rights reserved.
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license or royalty fees, to use, copy, modify, and distribute this
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*
*/
package diva.canvas.event;
import java.awt.event.InputEvent;
import java.awt.event.MouseEvent;
/** A class that accepts mouse events. Instances of this class
* are used by event-handling code to decide whether they are
* interested in a particular event.
*
* @version $Id$
* @author John Reekie
*/
public class MouseFilter {
/** The default mouse filter -- accepts button 1 with no
* modifiers.
*/
public static final MouseFilter defaultFilter = new MouseFilter(1);
/** The default selection filter -- accepts button 1 with <i>no</i>
* modifiers.
*/
public static final MouseFilter selectionFilter = new MouseFilter(1);
/** The alternate selection filter -- accepts button 1 with shift.
*/
public static final MouseFilter alternateSelectionFilter = new MouseFilter(
1, InputEvent.SHIFT_MASK);
/** The mouse button mask
*/
private int _buttonMask = InputEvent.BUTTON1_MASK | InputEvent.BUTTON2_MASK
| InputEvent.BUTTON3_MASK;
/** The modifier mask. The Macintosh requires META_MASK for selecting
* relations and right clicking.
*/
private int _modifierMask = InputEvent.SHIFT_MASK | InputEvent.CTRL_MASK
| InputEvent.META_MASK;
// Do not or these masks in, they will conflict with right mousing
// on transitions in modal models
//| InputEvent.ALT_MASK
//| InputEvent.ALT_GRAPH_MASK
//| InputEvent.META_MASK;
/** The modifier flags, after masking
*/
private int _modifierFlags = 0;
/** The button press to trap, or -1 if the button press number is not
* important, in which events will not be filtered based on press number.
*/
private int _pressNumber = -1;
///////////////////////////////////////////////////////////////////
//// constructors and public methods
/**
* Construct a mouse filter that responds to the given mouse buttons
* and modifier keys. The arguments must be constructed using the
* button masks defined by java.awt.event.MouseEvent. More than one
* button can be specified, in which case the filter will accept
* events from any of them. In any case, modifier keys are ignored.
*/
public MouseFilter(int button) {
// Why don't we be clever and figure out if the button number
// instead of mask is given? We know this works because we looked
// at the AWT source.
if (button <= 3) {
switch (button) {
case 1:
button = InputEvent.BUTTON1_MASK;
break;
case 2:
button = InputEvent.BUTTON2_MASK;
break;
case 3:
button = InputEvent.BUTTON3_MASK;
break;
}
}
// OK, so just set it.
// FIXME: check range.
_buttonMask = button;
}
/** Construct a mouse filter that responds to the given mouse
* buttons and modifier keys. The two arguments must be constructed
* using the button and modifier masks defined by
* java.awt.event.MouseEvent. More than one button can be specified,
* in which case the filter will accept events from any of them. The
* filter will accept modifier sets that exactly match modifiers.
*/
public MouseFilter(int button, int modifiers) {
this(button);
_modifierFlags = modifiers;
}
/**
* Construct a mouse filter that responds to the given mouse buttons
* and modifier keys. The three arguments must be constructed using
* the button and modifier masks defined by
* java.awt.event.MouseEvent. More than one button can be specified,
* in which case the filter will accept events triggered by any of
* them. The mask argument filters out modifiers that will be
* ignored; the filter will accept modifier sets that, after
* masking, exactly match modifiers.
*/
public MouseFilter(int button, int modifiers, int mask) {
this(button);
_modifierFlags = modifiers;
_modifierMask = mask;
}
/**
* Construct a mouse filter that responds to the given mouse buttons
* and modifier keys. The three arguments must be constructed using
* the button and modifier masks defined by
* java.awt.event.MouseEvent. More than one button can be specified,
* in which case the filter will accept events triggered by any of
* them. The mask argument filters out modifiers that will be
* ignored; the filter will accept modifier sets that, after
* masking, exactly match modifiers. The MouseFilter will only react to
* the press number given in the last argument. This will usually be one
* or two. Notice that if you want to react to drag events, they always
* have a press number of zero.
*/
public MouseFilter(int button, int modifiers, int mask, int pressNumber) {
this(button, modifiers, mask);
_pressNumber = pressNumber;
}
/**
* Test whether the given MouseEvent passes the filter.
*/
public boolean accept(MouseEvent event) {
if ((_pressNumber != -1) && (event.getClickCount() != _pressNumber)) {
return false;
}
int m = event.getModifiers();
// FIXME: Java people have broken the mask mechanism!
// When you right click, this gets called with m=4,
// indicating that the right mouse button was used.
// Unfortunately, the _modifierMask includes the bit
// corresponding to m=4 (for Shift?). Since no
// modifiers are required, _modifierFlags = 0, and
// this test is never satisfied by a right click.
// The result is that when you right click on a
// connection between actors, the interactor for
// connector does not accept the event, and the
// event gets passed to the background graph,
// which accepts it and produces the wrong
// context menu.
boolean val = ((m & _buttonMask) != 0)
&& (_modifierFlags == (m & _modifierMask));
// System.out.println("event = " + event);
// System.out.println("FILTER = " + this);
// System.out.println("ACCEPT? = " + val);
return val;
}
/** Print a useful description of the mouse filter.
*/
public String toString() {
StringBuffer result = new StringBuffer();
result.append(super.toString() + "; Button "
+ MouseEvent.getMouseModifiersText(_buttonMask)
+ "; Modifiers "
+ MouseEvent.getMouseModifiersText(_modifierFlags)
+ "; Modifier mask "
+ MouseEvent.getMouseModifiersText(_modifierMask)
+ "; Press Number " + _pressNumber);
return result.toString();
}
}