DragSourceDragEvent is
* delivered from the DragSourceContextPeer,
* via the DragSourceContext, to the DragSourceListener
* registered with that DragSourceContext and with its associated
* DragSource.
*
* The DragSourceDragEvent reports the target drop action
* and the user drop action that reflect the current state of
* the drag operation.
*
* Target drop action is one of DnDConstants that represents
* the drop action selected by the current drop target if this drop action is
* supported by the drag source or DnDConstants.ACTION_NONE if this
* drop action is not supported by the drag source.
*
* User drop action depends on the drop actions supported by the drag * source and the drop action selected by the user. The user can select a drop * action by pressing modifier keys during the drag operation: *
* Ctrl + Shift -> ACTION_LINK * Ctrl -> ACTION_COPY * Shift -> ACTION_MOVE ** If the user selects a drop action, the user drop action is one of *
DnDConstants that represents the selected drop action if this
* drop action is supported by the drag source or
* DnDConstants.ACTION_NONE if this drop action is not supported
* by the drag source.
*
* If the user doesn't select a drop action, the set of
* DnDConstants that represents the set of drop actions supported
* by the drag source is searched for DnDConstants.ACTION_MOVE,
* then for DnDConstants.ACTION_COPY, then for
* DnDConstants.ACTION_LINK and the user drop action is the
* first constant found. If no constant is found the user drop action
* is DnDConstants.ACTION_NONE.
*
* @version 1.29, 12/19/03
* @since 1.2
*
*/
public class DragSourceDragEvent extends DragSourceEvent {
private static final long serialVersionUID = 481346297933902471L;
/**
* Constructs a DragSourceDragEvent.
* This class is typically
* instantiated by the DragSourceContextPeer
* rather than directly
* by client code.
* The coordinates for this DragSourceDragEvent
* are not specified, so getLocation will return
* null for this event.
*
* The arguments dropAction and action should
* be one of DnDConstants that represents a single action.
* The argument modifiers should be either a bitwise mask
* of old java.awt.event.InputEvent.*_MASK constants or a
* bitwise mask of extended java.awt.event.InputEvent.*_DOWN_MASK
* constants.
* This constructor does not throw any exception for invalid dropAction,
* action and modifiers.
*
* @param dsc the DragSourceContext that is to manage
* notifications for this event.
* @param dropAction the user drop action.
* @param action the target drop action.
* @param modifiers the modifier keys down during event (shift, ctrl,
* alt, meta)
* Either extended _DOWN_MASK or old _MASK modifiers
* should be used, but both models should not be mixed
* in one event. Use of the extended modifiers is
* preferred.
*
* @throws IllegalArgumentException if dsc is null.
*
* @see java.awt.event.InputEvent
* @see DragSourceEvent#getLocation
*/
public DragSourceDragEvent(DragSourceContext dsc, int dropAction,
int action, int modifiers) {
super(dsc);
targetActions = action;
gestureModifiers = modifiers;
this.dropAction = dropAction;
if ((modifiers & ~(JDK_1_3_MODIFIERS | JDK_1_4_MODIFIERS)) != 0) {
invalidModifiers = true;
} else if ((getGestureModifiers() != 0) && (getGestureModifiersEx() == 0)) {
setNewModifiers();
} else if ((getGestureModifiers() == 0) && (getGestureModifiersEx() != 0)) {
setOldModifiers();
} else {
invalidModifiers = true;
}
}
/**
* Constructs a DragSourceDragEvent given the specified
* DragSourceContext, user drop action, target drop action,
* modifiers and coordinates.
*
* The arguments dropAction and action should
* be one of DnDConstants that represents a single action.
* The argument modifiers should be either a bitwise mask
* of old java.awt.event.InputEvent.*_MASK constants or a
* bitwise mask of extended java.awt.event.InputEvent.*_DOWN_MASK
* constants.
* This constructor does not throw any exception for invalid dropAction,
* action and modifiers.
*
* @param dsc the DragSourceContext associated with this
* event.
* @param dropAction the user drop action.
* @param action the target drop action.
* @param modifiers the modifier keys down during event (shift, ctrl,
* alt, meta)
* Either extended _DOWN_MASK or old _MASK modifiers
* should be used, but both models should not be mixed
* in one event. Use of the extended modifiers is
* preferred.
* @param x the horizontal coordinate for the cursor location
* @param y the vertical coordinate for the cursor location
*
* @throws IllegalArgumentException if dsc is null.
*
* @see java.awt.event.InputEvent
* @since 1.4
*/
public DragSourceDragEvent(DragSourceContext dsc, int dropAction,
int action, int modifiers, int x, int y) {
super(dsc, x, y);
targetActions = action;
gestureModifiers = modifiers;
this.dropAction = dropAction;
if ((modifiers & ~(JDK_1_3_MODIFIERS | JDK_1_4_MODIFIERS)) != 0) {
invalidModifiers = true;
} else if ((getGestureModifiers() != 0) && (getGestureModifiersEx() == 0)) {
setNewModifiers();
} else if ((getGestureModifiers() == 0) && (getGestureModifiersEx() != 0)) {
setOldModifiers();
} else {
invalidModifiers = true;
}
}
/**
* This method returns the target drop action.
*
* @return the target drop action.
*/
public int getTargetActions() {
return targetActions;
}
private static final int JDK_1_3_MODIFIERS = InputEvent.SHIFT_DOWN_MASK - 1;
private static final int JDK_1_4_MODIFIERS =
((InputEvent.ALT_GRAPH_DOWN_MASK << 1) - 1) & ~JDK_1_3_MODIFIERS;
/**
* This method returns an int representing
* the current state of the input device modifiers
* associated with the user's gesture. Typically these
* would be mouse buttons or keyboard modifiers.
*
* If the modifiers passed to the constructor
* are invalid, this method returns them unchanged.
*
* @return the current state of the input device modifiers
*/
public int getGestureModifiers() {
return invalidModifiers ? gestureModifiers : gestureModifiers & JDK_1_3_MODIFIERS;
}
/**
* This method returns an int representing
* the current state of the input device extended modifiers
* associated with the user's gesture.
* See {@link InputEvent#getModifiersEx}
*
* If the modifiers passed to the constructor
* are invalid, this method returns them unchanged.
*
* @return the current state of the input device extended modifiers
* @since 1.4
*/
public int getGestureModifiersEx() {
return invalidModifiers ? gestureModifiers : gestureModifiers & JDK_1_4_MODIFIERS;
}
/**
* This method returns the user drop action.
*
* @return the user drop action.
*/
public int getUserAction() { return dropAction; }
/**
* This method returns the logical intersection of the user drop action,
* the target drop action and the set of drop actions supported by
* the drag source.
*
* @return the logical intersection of the user drop action, the target drop
* action and the set of drop actions supported by the drag source.
*/
public int getDropAction() {
return dropAction & targetActions & getDragSourceContext().getSourceActions();
}
/*
* fields
*/
/**
* The target drop action.
*
* @serial
*/
private int targetActions = DnDConstants.ACTION_NONE;
/**
* The user drop action.
*
* @serial
*/
private int dropAction = DnDConstants.ACTION_NONE;
/**
* The state of the input device modifiers associated with the user
* gesture.
*
* @serial
*/
private int gestureModifiers = 0;
/**
* Indicates whether the gestureModifiers are invalid.
*
* @serial
*/
private boolean invalidModifiers;
/**
* Sets new modifiers by the old ones.
* The mouse modifiers have higher priority than overlaying key
* modifiers.
*/
private void setNewModifiers() {
if ((gestureModifiers & InputEvent.BUTTON1_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON1_DOWN_MASK;
}
if ((gestureModifiers & InputEvent.BUTTON2_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON2_DOWN_MASK;
}
if ((gestureModifiers & InputEvent.BUTTON3_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON3_DOWN_MASK;
}
if ((gestureModifiers & InputEvent.SHIFT_MASK) != 0) {
gestureModifiers |= InputEvent.SHIFT_DOWN_MASK;
}
if ((gestureModifiers & InputEvent.CTRL_MASK) != 0) {
gestureModifiers |= InputEvent.CTRL_DOWN_MASK;
}
if ((gestureModifiers & InputEvent.ALT_GRAPH_MASK) != 0) {
gestureModifiers |= InputEvent.ALT_GRAPH_DOWN_MASK;
}
}
/**
* Sets old modifiers by the new ones.
*/
private void setOldModifiers() {
if ((gestureModifiers & InputEvent.BUTTON1_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON1_MASK;
}
if ((gestureModifiers & InputEvent.BUTTON2_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON2_MASK;
}
if ((gestureModifiers & InputEvent.BUTTON3_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.BUTTON3_MASK;
}
if ((gestureModifiers & InputEvent.SHIFT_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.SHIFT_MASK;
}
if ((gestureModifiers & InputEvent.CTRL_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.CTRL_MASK;
}
if ((gestureModifiers & InputEvent.ALT_GRAPH_DOWN_MASK) != 0) {
gestureModifiers |= InputEvent.ALT_GRAPH_MASK;
}
}
}