CtScannerListener.java

/**
 * Copyright (C) 2006-2017 INRIA and contributors
 * Spoon - http://spoon.gforge.inria.fr/
 *
 * This software is governed by the CeCILL-C License under French law and
 * abiding by the rules of distribution of free software. You can use, modify
 * and/or redistribute the software under the terms of the CeCILL-C license as
 * circulated by CEA, CNRS and INRIA at http://www.cecill.info.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the CeCILL-C License for more details.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL-C license and that you accept its terms.
 */
package spoon.reflect.visitor.chain;

import spoon.reflect.declaration.CtElement;

/**
 * Responsible for performing an action when a scanner enters/exits a node while scanning the AST.
 */
public interface CtScannerListener {
	/**
	 * Called before the scanner enters an element
	 *
	 * @param element the element about to be scanned.
	 * @return a {@link ScanningMode} that drives how the scanner processes this element and its children.
	 * For instance, returning {@link ScanningMode#SKIP_ALL} causes that element and all children to be skipped and {@link #exit(CtElement)} are be NOT called for that element.
	 */
	ScanningMode enter(CtElement element);

	/**
	 * This method is called after the element and all its children have been visited.
	 * This method is NOT called if an exception is thrown in {@link #enter(CtElement)} or during the scanning of the element or any of its children element.
	 * This method is NOT called for an element for which {@link #enter(CtElement)} returned {@link ScanningMode#SKIP_ALL}.
	 *
	 * @param element the element that has just been scanned.
	 */
	void exit(CtElement element);
}