Interaction.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
 * KIND, EITHER EXPRESSED OR IMPLIED, AS TO ANY MATTER INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR PURPOSE
 * OR MERCHANTABILITY, EXCLUSIVITY, OR RESULTS OBTAINED FROM USE OF THE MATERIAL. CARNEGIE MELLON UNIVERSITY DOES NOT
 * 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
 * files ("Third Party Software"). The Third Party Software that is used by this program is dependent upon your system
 * configuration. By using this program, You agree to comply with any and all relevant Third Party Software terms and
 * conditions contained in any such Third Party Software or separate license file distributed with such Third Party
 * Software. The parties who own the Third Party Software ("Third Party Licensors") are intended third party benefici-
 * aries to this license with respect to the terms applicable to their Third Party Software. Third Party Software li-
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 */
package org.osate.ge.gef.ui.editor;

import javafx.scene.Cursor;
import javafx.scene.input.InputEvent;

/**
 * An interaction handles a series of events. {@link InputEventHandler} instances create interactions in response to events.
 */
public interface Interaction extends AutoCloseable {
	/**
	 * The state of the interaction.
	 */
	enum InteractionState {
		/**
		 * An interaction is still in progress and should receive input events.
		 */
		IN_PROGRESS,
		/**
		 * The interaction has been completed
		 */
		COMPLETE
	}

	/**
	 * Completes the interaction. Makes any pending actions, cleans up the interaction and restores the scene graph to the
	 * original state if needed.
	 */
	@Override
	void close();

	/**
	* Returns the mouse cursor based that should override the default cursor.
	* @return the cursor that should be used or null if the cursor shouldn't be overridden.
	*/
	Cursor getCursor();

	/**
	 * Handles an input event.
	 * @param e the input event to handle.
	 * @return the new state of the interaction. Should return {@link InteractionState#COMPLETE} when the final event for the interaction has been handled.
	 */
	InteractionState handleEvent(InputEvent e);
}