1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package jdk.nashorn.internal.ir;
  26 
  27 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
  28 
  29 
  30 /**
  31  * Interface for nodes that can be part of the lexical context.
  32  * @see LexicalContext
  33  */
  34 public interface LexicalContextNode {
  35     /**
  36      * Accept function for the node given a lexical context. It must be prepared
  37      * to replace itself if present in the lexical context
  38      *
  39      * @param lc      lexical context
  40      * @param visitor node visitor
  41      *
  42      * @return new node or same node depending on state change
  43      */
  44     Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor);
  45 
  46     // Would be a default method on Java 8
  47     /**
  48      * Helper class for accept for items of this lexical context, delegates to the
  49      * subclass accept and makes sure that the node is on the context before accepting
  50      * and gets popped after accepting (and that the stack is consistent in that the
  51      * node has been replaced with the possible new node resulting in visitation)
  52      */
  53     static class Acceptor {
  54         static Node accept(final LexicalContextNode node, final NodeVisitor<? extends LexicalContext> visitor) {
  55             final LexicalContext lc = visitor.getLexicalContext();
  56             lc.push(node);
  57             final Node newNode = node.accept(lc, visitor);
  58             return lc.pop(newNode);
  59         }
  60     }
  61 }