1/* 2 [The "BSD license"] 3 Copyright (c) 2005-2009 Terence Parr 4 All rights reserved. 5 6 Redistribution and use in source and binary forms, with or without 7 modification, are permitted provided that the following conditions 8 are met: 9 1. Redistributions of source code must retain the above copyright 10 notice, this list of conditions and the following disclaimer. 11 2. Redistributions in binary form must reproduce the above copyright 12 notice, this list of conditions and the following disclaimer in the 13 documentation and/or other materials provided with the distribution. 14 3. The name of the author may not be used to endorse or promote products 15 derived from this software without specific prior written permission. 16 17 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28package org.antlr.runtime.tree; 29 30import java.util.List; 31 32public class RewriteRuleSubtreeStream extends RewriteRuleElementStream { 33 34 public RewriteRuleSubtreeStream(TreeAdaptor adaptor, String elementDescription) { 35 super(adaptor, elementDescription); 36 } 37 38 /** Create a stream with one element */ 39 public RewriteRuleSubtreeStream(TreeAdaptor adaptor, 40 String elementDescription, 41 Object oneElement) 42 { 43 super(adaptor, elementDescription, oneElement); 44 } 45 46 /** Create a stream, but feed off an existing list */ 47 public RewriteRuleSubtreeStream(TreeAdaptor adaptor, 48 String elementDescription, 49 List elements) 50 { 51 super(adaptor, elementDescription, elements); 52 } 53 54 /** Treat next element as a single node even if it's a subtree. 55 * This is used instead of next() when the result has to be a 56 * tree root node. Also prevents us from duplicating recently-added 57 * children; e.g., ^(type ID)+ adds ID to type and then 2nd iteration 58 * must dup the type node, but ID has been added. 59 * 60 * Referencing a rule result twice is ok; dup entire tree as 61 * we can't be adding trees as root; e.g., expr expr. 62 * 63 * Hideous code duplication here with super.next(). Can't think of 64 * a proper way to refactor. This needs to always call dup node 65 * and super.next() doesn't know which to call: dup node or dup tree. 66 */ 67 public Object nextNode() { 68 //System.out.println("nextNode: elements="+elements+", singleElement="+((Tree)singleElement).toStringTree()); 69 int n = size(); 70 if ( dirty || (cursor>=n && n==1) ) { 71 // if out of elements and size is 1, dup (at most a single node 72 // since this is for making root nodes). 73 Object el = _next(); 74 return adaptor.dupNode(el); 75 } 76 // test size above then fetch 77 Object tree = _next(); 78 while (adaptor.isNil(tree) && adaptor.getChildCount(tree) == 1) 79 tree = adaptor.getChild(tree, 0); 80 //System.out.println("_next="+((Tree)tree).toStringTree()); 81 Object el = adaptor.dupNode(tree); // dup just the root (want node here) 82 return el; 83 } 84 85 protected Object dup(Object el) { 86 return adaptor.dupTree(el); 87 } 88}