Interactor.java

/*
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 *
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package diva.canvas.interactor;

import diva.canvas.event.LayerEvent;
import diva.canvas.event.LayerListener;
import diva.canvas.event.LayerMotionListener;
import diva.canvas.event.MouseFilter;

/**
 * An object that encapsulate the interaction that a figure plays in
 * an interactive application. Typically, all objects of a certain
 * type (nodes in a graph viewer, for example) all have the same
 * interactor given to them, so that they behave the same. Each
 * interactor is thus attached to one or more figures in a canvas.
 *
 * When a mouse event occurs on the figure canvas, the event dispatch
 * code in the figure canvas searches for the top-most figure
 * underneath the mouse, and then searches up the tree of figures
 * looking for an interactor that can handle that event.
 *
 * @version $Id$
 * @author John Reekie
 */
public interface Interactor extends LayerListener, LayerMotionListener {
    /** Test is the interactor is prepared to accept this event.  If
     * so, the event is passed to the interactor for handling.  This
     * method is called only for the mouse-pressed and mouse-entered
     * events. If that event is accepted, other events of the same
     * series (dragged and released, or moved and exited,
     * respectively) are passed to the interactor without calling
     * this method to check. The mouse-entered event is called only
     * if isMotionEnabled() returns true.
     */
    public boolean accept(LayerEvent event);

    /** Get the mouse filter used by this interactor to
     * decide whether to accept an event. The result may
     * be null.
     */
    public MouseFilter getMouseFilter();

    /** Test the consuming flag of this interactor. If this flag is
     * set, the interactor expects is indicating that all events
     * that it will accept should be consumed.
     */
    public boolean isConsuming();

    /** Test the enabled flag of this interactor. If true, the
     * interactor is prepared to handle layer events of all kinds.
     */
    public boolean isEnabled();

    /** Test the motion enabled flag of this interactor. If true, the
     * interactor is prepared to handle layer motion events.
     */
    public boolean isMotionEnabled();

    /** Set the enabled flag of this interactor.  If true, the
     * interactor is prepared to handle layer events. The default
     * setting of this flag should be <b>true</b>.
     */
    public void setEnabled(boolean flag);

    /** Set the mouse filter of this interactor. If a filter is
     * set with this method, the interactor is expected to use the
     * filter within its accept() method.
     */
    public void setMouseFilter(MouseFilter filter);
}