001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 021 package org.apache.directory.shared.ldap.trigger; 022 023 024 import java.io.StringReader; 025 import java.text.ParseException; 026 027 import org.apache.directory.shared.i18n.I18n; 028 import org.apache.directory.shared.ldap.schema.NormalizerMappingResolver; 029 030 import antlr.RecognitionException; 031 import antlr.TokenStreamException; 032 033 034 /** 035 * A reusable wrapper around the ANTLR generated parser for a 036 * TriggerSpecification. This class enables the reuse of the antlr parser/lexer 037 * pair without having to recreate them every time. 038 * 039 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 040 * @version $Rev:$, $Date:$ 041 */ 042 public class TriggerSpecificationParser 043 { 044 /** the antlr generated parser being wrapped */ 045 private ReusableAntlrTriggerSpecificationParser parser; 046 047 /** the antlr generated lexer being wrapped */ 048 private ReusableAntlrTriggerSpecificationLexer lexer; 049 050 private final boolean isNormalizing; 051 052 053 /** 054 * Creates a TriggerSpecification parser. 055 */ 056 public TriggerSpecificationParser() 057 { 058 this.lexer = new ReusableAntlrTriggerSpecificationLexer( new StringReader( "" ) ); 059 this.parser = new ReusableAntlrTriggerSpecificationParser( lexer ); 060 061 this.parser.init(); // this method MUST be called while we cannot do 062 // constructor overloading for antlr generated parser 063 this.isNormalizing = false; 064 } 065 066 067 /** 068 * Creates a normalizing TriggerSpecification parser. 069 */ 070 public TriggerSpecificationParser( NormalizerMappingResolver resolver ) 071 { 072 this.lexer = new ReusableAntlrTriggerSpecificationLexer( new StringReader( "" ) ); 073 this.parser = new ReusableAntlrTriggerSpecificationParser( lexer ); 074 075 this.parser.setNormalizerMappingResolver( resolver ); 076 this.parser.init(); // this method MUST be called while we cannot do 077 // constructor overloading for ANTLR generated parser 078 this.isNormalizing = true; 079 } 080 081 082 /** 083 * Initializes the plumbing by creating a pipe and coupling the parser/lexer 084 * pair with it. 085 * 086 * @param 087 * spec the specification to be parsed 088 */ 089 private synchronized void reset( String spec ) 090 { 091 StringReader in = new StringReader( spec ); 092 this.lexer.prepareNextInput( in ); 093 this.parser.resetState(); 094 } 095 096 097 /** 098 * Parses an TriggerSpecification without exhausting the parser. 099 * 100 * @param spec 101 * the specification to be parsed 102 * @return the specification bean 103 * @throws ParseException 104 * if there are any recognition errors (bad syntax) 105 */ 106 public synchronized TriggerSpecification parse( String spec ) throws ParseException 107 { 108 TriggerSpecification triggerSpecification = null; 109 110 if ( spec == null || spec.trim().equals( "" ) ) 111 { 112 return null; 113 } 114 115 reset( spec ); // reset and initialize the parser / lexer pair 116 117 try 118 { 119 triggerSpecification = this.parser.wrapperEntryPoint(); 120 } 121 catch ( TokenStreamException e ) 122 { 123 String msg = I18n.err( I18n.ERR_04333, spec, e.getLocalizedMessage() ); 124 throw new ParseException( msg, 0 ); 125 } 126 catch ( RecognitionException e ) 127 { 128 String msg = I18n.err( I18n.ERR_04333, spec, e.getLocalizedMessage() ); 129 throw new ParseException( msg, e.getColumn() ); 130 } 131 132 return triggerSpecification; 133 134 } 135 136 137 /** 138 * Tests to see if this parser is normalizing. 139 * 140 * @return true if it normalizes false otherwise 141 */ 142 public boolean isNormizing() 143 { 144 return this.isNormalizing; 145 } 146 }