content: /*
   * Copyright (c) 2006, 2020, 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 openjdk.source.util;
  
  import openjdk.source.doctree.DocTree;
  
  /**
   * A DocTreeVisitor 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.
   *
   * @since 1.8
   */
  public class DocTreePathScanner<R, P> extends DocTreeScanner<R, P> {
      /**
       * Constructs a {@code DocTreePathScanner}.
       */
      public DocTreePathScanner() {}
  
      /**
       * Scans a tree from a position identified by a tree path.
       * @param path the path
       * @param p a value to be passed to visitor methods
       * @return the result returned from the main visitor method
       */
      public R scan(DocTreePath path, P p) {
          this.path = path;
          try {
              return path.getLeaf().accept(this, p);
          } finally {
              this.path = null;
          }
      }
  
      /**
       * Scans a single node.
       * The current path is updated for the duration of the scan.
       * @param tree the tree to be scanned
       * @param p a value to be passed to visitor methods
       * @return the result returned from the main visitor method
       */
      @Override
      public R scan(DocTree tree, P p) {
          if (tree == null)
              return null;
  
          DocTreePath prev = path;
          path = new DocTreePath(path, tree);
          try {
              return tree.accept(this, p);
          } finally {
              path = prev;
          }
      }
  
      /**
       * Returns the current path for the node, as built up by the currently
       * active set of scan calls.
       * @return the current path
       */
      public DocTreePath getCurrentPath() {
          return path;
      }
  
      private DocTreePath path;
  }
  