/*

 * Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.source.util;

import com.sun.source.tree.*;

/**

 * A TreeVisitor that visits all the child tree nodes, and provides

 * support for maintaining a path for the parent nodes.

 * To visit nodes of a particular type, just override the

 * corresponding visitorXYZ method.

 * Inside your method, call super.visitXYZ to visit descendant

 * nodes.

 *

 * @author Jonathan Gibbons

 * @since 1.6

 */

@jdk.Supported

public class TreePathScanner<R, P> extends TreeScanner<R, P> {

    /**

     * Scan a tree from a position identified by a TreePath.

     */

    public R scan(TreePath path, P p) {

        this.path = path;

        try {

            return path.getLeaf().accept(this, p);

        } finally {

            this.path = null;

        }

    }

    /**

     * Scan a single node.

     * The current path is updated for the duration of the scan.

     */

    @Override

    public R scan(Tree tree, P p) {

        if (tree == null)

            return null;

        TreePath prev = path;

        path = new TreePath(path, tree);

        try {

            return tree.accept(this, p);

        } finally {

            path = prev;

        }

    }

    /**

     * Get the current path for the node, as built up by the currently

     * active set of scan calls.

     */

    public TreePath getCurrentPath() {

        return path;

    }

    private TreePath path;

}