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 */ 28 package org.antlr.runtime; 29 30 import org.antlr.runtime.tree.*; 31 32 /** The root of the ANTLR exception hierarchy. 33 * 34 * To avoid English-only error messages and to generally make things 35 * as flexible as possible, these exceptions are not created with strings, 36 * but rather the information necessary to generate an error. Then 37 * the various reporting methods in Parser and Lexer can be overridden 38 * to generate a localized error message. For example, MismatchedToken 39 * exceptions are built with the expected token type. 40 * So, don't expect getMessage() to return anything. 41 * 42 * Note that as of Java 1.4, you can access the stack trace, which means 43 * that you can compute the complete trace of rules from the start symbol. 44 * This gives you considerable context information with which to generate 45 * useful error messages. 46 * 47 * ANTLR generates code that throws exceptions upon recognition error and 48 * also generates code to catch these exceptions in each rule. If you 49 * want to quit upon first error, you can turn off the automatic error 50 * handling mechanism using rulecatch action, but you still need to 51 * override methods mismatch and recoverFromMismatchSet. 52 * 53 * In general, the recognition exceptions can track where in a grammar a 54 * problem occurred and/or what was the expected input. While the parser 55 * knows its state (such as current input symbol and line info) that 56 * state can change before the exception is reported so current token index 57 * is computed and stored at exception time. From this info, you can 58 * perhaps print an entire line of input not just a single token, for example. 59 * Better to just say the recognizer had a problem and then let the parser 60 * figure out a fancy report. 61 */ 62 public class RecognitionException extends Exception { 63 /** What input stream did the error occur in? */ 64 public transient IntStream input; 65 66 /** What is index of token/char were we looking at when the error occurred? */ 67 public int index; 68 69 /** The current Token when an error occurred. Since not all streams 70 * can retrieve the ith Token, we have to track the Token object. 71 * For parsers. Even when it's a tree parser, token might be set. 72 */ 73 public Token token; 74 75 /** If this is a tree parser exception, node is set to the node with 76 * the problem. 77 */ 78 public Object node; 79 80 /** The current char when an error occurred. For lexers. */ 81 public int c; 82 83 /** Track the line at which the error occurred in case this is 84 * generated from a lexer. We need to track this since the 85 * unexpected char doesn't carry the line info. 86 */ 87 public int line; 88 89 public int charPositionInLine; 90 91 /** If you are parsing a tree node stream, you will encounter som 92 * imaginary nodes w/o line/col info. We now search backwards looking 93 * for most recent token with line/col info, but notify getErrorHeader() 94 * that info is approximate. 95 */ 96 public boolean approximateLineInfo; 97 98 /** Used for remote debugger deserialization */ 99 public RecognitionException() { 100 } 101 102 public RecognitionException(IntStream input) { 103 this.input = input; 104 this.index = input.index(); 105 if ( input instanceof TokenStream ) { 106 this.token = ((TokenStream)input).LT(1); 107 this.line = token.getLine(); 108 this.charPositionInLine = token.getCharPositionInLine(); 109 } 110 if ( input instanceof TreeNodeStream ) { 111 extractInformationFromTreeNodeStream(input); 112 } 113 else if ( input instanceof CharStream ) { 114 this.c = input.LA(1); 115 this.line = ((CharStream)input).getLine(); 116 this.charPositionInLine = ((CharStream)input).getCharPositionInLine(); 117 } 118 else { 119 this.c = input.LA(1); 120 } 121 } 122 123 protected void extractInformationFromTreeNodeStream(IntStream input) { 124 TreeNodeStream nodes = (TreeNodeStream)input; 125 this.node = nodes.LT(1); 126 TreeAdaptor adaptor = nodes.getTreeAdaptor(); 127 Token payload = adaptor.getToken(node); 128 if ( payload!=null ) { 129 this.token = payload; 130 if ( payload.getLine()<= 0 ) { 131 // imaginary node; no line/pos info; scan backwards 132 int i = -1; 133 Object priorNode = nodes.LT(i); 134 while ( priorNode!=null ) { 135 Token priorPayload = adaptor.getToken(priorNode); 136 if ( priorPayload!=null && priorPayload.getLine()>0 ) { 137 // we found the most recent real line / pos info 138 this.line = priorPayload.getLine(); 139 this.charPositionInLine = priorPayload.getCharPositionInLine(); 140 this.approximateLineInfo = true; 141 break; 142 } 143 --i; 144 priorNode = nodes.LT(i); 145 } 146 } 147 else { // node created from real token 148 this.line = payload.getLine(); 149 this.charPositionInLine = payload.getCharPositionInLine(); 150 } 151 } 152 else if ( this.node instanceof Tree) { 153 this.line = ((Tree)this.node).getLine(); 154 this.charPositionInLine = ((Tree)this.node).getCharPositionInLine(); 155 if ( this.node instanceof CommonTree) { 156 this.token = ((CommonTree)this.node).token; 157 } 158 } 159 else { 160 int type = adaptor.getType(this.node); 161 String text = adaptor.getText(this.node); 162 this.token = new CommonToken(type, text); 163 } 164 } 165 166 /** Return the token type or char of the unexpected input element */ 167 public int getUnexpectedType() { 168 if ( input instanceof TokenStream ) { 169 return token.getType(); 170 } 171 else if ( input instanceof TreeNodeStream ) { 172 TreeNodeStream nodes = (TreeNodeStream)input; 173 TreeAdaptor adaptor = nodes.getTreeAdaptor(); 174 return adaptor.getType(node); 175 } 176 else { 177 return c; 178 } 179 } 180 } 181
