org.eclipse.osbp.xtext.action/src/org/eclipse/osbp/xtext/action/common/E4Helper.java

/**
 *                                                                            
 *  Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany) 
 *                                                                            
 *  All rights reserved. This program and the accompanying materials           
 *  are made available under the terms of the Eclipse Public License 2.0        
 *  which accompanies this distribution, and is available at                  
 *  https://www.eclipse.org/legal/epl-2.0/                                 
 *                                 
 *  SPDX-License-Identifier: EPL-2.0                                 
 *                                                                            
 *  Contributors:                                                      
 * 	   Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation
 * 
 */
package org.eclipse.osbp.xtext.action.common;

import org.eclipse.e4.ui.model.application.ui.MElementContainer;
import org.eclipse.e4.ui.model.application.ui.MUIElement;
import org.eclipse.e4.ui.model.application.ui.basic.MPart;

public class E4Helper {
	private E4Helper() {
	}

	public static final MUIElement getPart(boolean next, MUIElement element, boolean wasActive) {
		int direction = +1;
		if(!next) {
			direction = -1;
		}
		MElementContainer<MUIElement> parent = element.getParent();
		MUIElement child = null;
		if (wasActive) {
			int index = parent.getChildren().size() - 1;
			if(!next) {
				index = 0;
			}
			if (parent.getChildren().indexOf(element) == index) {
				return getPart(next, parent, wasActive);
			} else {
				child = parent.getChildren().get(parent.getChildren().indexOf(element) + direction);
			}
		} else {
			child = parent.getChildren().get(parent.getChildren().indexOf(element));
		}
		if (child instanceof MPart) {
			return child;
		}
		if (child instanceof MElementContainer<?> && !((MElementContainer<?>) child).getChildren().isEmpty()) {
			int index = 0;
			if(!next) {
				index = ((MElementContainer<?>) child).getChildren().size() - 1;
			}
			return getPart(next, (MUIElement) ((MElementContainer<?>) child).getChildren().get(index), false);
		}
		if (parent instanceof MElementContainer<?> && !parent.getChildren().isEmpty()) {
			int index = 0;
			if(!next) {
				index = parent.getChildren().size() - 1;
			}
			return getPart(next, (MUIElement) parent.getChildren().get(index), false);
		}
		return null;
	}
}