| /* |
| * Copyright (C) 2007-2010 JĂșlio Vilmar Gesser. |
| * Copyright (C) 2011, 2013-2016 The JavaParser Team. |
| * |
| * This file is part of JavaParser. |
| * |
| * JavaParser can be used either under the terms of |
| * a) the GNU Lesser General Public License as published by |
| * the Free Software Foundation, either version 3 of the License, or |
| * (at your option) any later version. |
| * b) the terms of the Apache License |
| * |
| * You should have received a copy of both licenses in LICENCE.LGPL and |
| * LICENCE.APACHE. Please refer to those files for details. |
| * |
| * JavaParser 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 |
| * GNU Lesser General Public License for more details. |
| */ |
| |
| package com.github.javaparser.ast.visitor; |
| |
| import com.github.javaparser.ast.Node; |
| |
| import java.util.ArrayList; |
| import java.util.LinkedList; |
| import java.util.Queue; |
| |
| /** |
| * Iterate over all the nodes in (a part of) the AST. In contrast to the visit methods in Node, these methods are |
| * implemented in a simple recursive way which should be more efficient. A disadvantage is that they cannot be quit in |
| * the middle of their traversal. |
| */ |
| public abstract class TreeVisitor { |
| |
| public void visitLeavesFirst(Node node) { |
| for (Node child : node.getChildNodes()) { |
| visitLeavesFirst(child); |
| } |
| process(node); |
| } |
| |
| /** |
| * Performs a pre-order node traversal starting with a given node. When each node is visited, {@link #process(Node)} |
| * is called for further processing. |
| * |
| * @param node The node at which the traversal begins. |
| * @see <a href="https://en.wikipedia.org/wiki/Pre-order">Pre-order traversal</a> |
| */ |
| public void visitPreOrder(Node node) { |
| process(node); |
| new ArrayList<>(node.getChildNodes()).forEach(this::visitPreOrder); |
| } |
| |
| /** |
| * Performs a post-order node traversal starting with a given node. When each node is visited, {@link |
| * #process(Node)} is called for further processing. |
| * |
| * @param node The node at which the traversal begins. |
| * @see <a href="https://en.wikipedia.org/wiki/Post-order">Post-order traversal</a> |
| */ |
| public void visitPostOrder(Node node) { |
| new ArrayList<>(node.getChildNodes()).forEach(this::visitPostOrder); |
| process(node); |
| } |
| |
| /** |
| * Performs a pre-order node traversal starting with a given node. When each node is visited, {@link #process(Node)} |
| * is called for further processing. |
| * |
| * @param node The node at which the traversal begins. |
| * @see <a href="https://en.wikipedia.org/wiki/Pre-order">Pre-order traversal</a> |
| * @deprecated As of release 3.1.0, replaced by {@link #visitPreOrder(Node)} |
| */ |
| @Deprecated |
| public void visitDepthFirst(Node node) { |
| visitPreOrder(node); |
| } |
| |
| /** |
| * https://en.wikipedia.org/wiki/Breadth-first_search |
| * |
| * @param node the start node, and the first one that is passed to process(node). |
| */ |
| public void visitBreadthFirst(Node node) { |
| final Queue<Node> queue = new LinkedList<>(); |
| queue.offer(node); |
| while (queue.size() > 0) { |
| final Node head = queue.peek(); |
| for (Node child : head.getChildNodes()) { |
| queue.offer(child); |
| } |
| process(queue.poll()); |
| } |
| } |
| |
| /** |
| * Process the given node. |
| * |
| * @param node The current node to process. |
| */ |
| public abstract void process(Node node); |
| |
| /** |
| * Performs a simple traversal over all nodes that have the passed node as their parent. |
| */ |
| public void visitDirectChildren(Node node) { |
| new ArrayList<>(node.getChildNodes()).forEach(this::process); |
| } |
| } |