InputEventHandler.java
/**
* Copyright (c) 2004-2025 Carnegie Mellon University and others. (see Contributors file).
* All Rights Reserved.
*
* NO WARRANTY. ALL MATERIAL IS FURNISHED ON AN "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY
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* MAKE ANY WARRANTY OF ANY KIND WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT.
*
* This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0
* which is available at https://www.eclipse.org/legal/epl-2.0/
* SPDX-License-Identifier: EPL-2.0
*
* Created, in part, with funding and support from the United States Government. (see Acknowledgments file).
*
* This program includes and/or can make use of certain third party source code, object code, documentation and other
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package org.osate.ge.gef.ui.editor;
import javafx.scene.Cursor;
import javafx.scene.input.InputEvent;
import javafx.scene.input.MouseEvent;
/**
* Interface for objects which handle input events. Such handlers may optionally start an interaction. Once an interaction is started,
* events are passed to the interaction rather than the input event handlers until the interaction is complete.
*/
public interface InputEventHandler {
/**
* The result of handling an event
*/
static class HandledEvent {
private static final HandledEvent CONSUMED = new HandledEvent(null);
/**
* If an interaction is started, then this contains the new interaction.
*/
final Interaction newInteraction;
private HandledEvent(final Interaction newInteraction) {
this.newInteraction = newInteraction;
}
/**
* Returns an instance used in cases where the event has been handled, an interaction was not started, and
* the event should not be passed to subsequent event handlers.
* @return the instance.
*/
public static HandledEvent consumed() {
return CONSUMED;
}
/**
* Returns an instance that indicates that the event has been handled and a new interaction has started.
* @param interaction the new interaction
* @return the instance
*/
public static HandledEvent newInteraction(final Interaction interaction) {
return new HandledEvent(interaction);
}
}
/**
* Returns the mouse cursor based that should override the default cursor.
* @param mouseMoveEvent is the mouse move event containing the location of the cursor.
* @return the cursor that should be used or null if the cursor shouldn't be overridden.
*/
Cursor getCursor(final MouseEvent mouseMoveEvent);
/**
* Handles the event.
* @param e the new input event
* @return the result of handling the event. If the event was not consumed by the handler, then null is returned.
*/
HandledEvent handleEvent(InputEvent e);
}