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.subtree;
022
023
024 import java.io.StringReader;
025 import java.text.ParseException;
026 import java.util.Map;
027
028 import org.apache.directory.shared.i18n.I18n;
029 import org.apache.directory.shared.ldap.schema.NormalizerMappingResolver;
030 import org.apache.directory.shared.ldap.schema.normalizers.OidNormalizer;
031
032 import antlr.RecognitionException;
033 import antlr.TokenStreamException;
034
035
036 /**
037 * A reusable wrapper around the antlr generated parser for an LDAP subtree
038 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html">
039 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair
040 * without having to recreate the pair every time.
041 *
042 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
043 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
044 * @version $Rev: 919765 $
045 */
046 public class SubtreeSpecificationParser
047 {
048 /** the antlr generated parser being wrapped */
049 private ReusableAntlrSubtreeSpecificationParser parser;
050
051 /** the antlr generated lexer being wrapped */
052 private ReusableAntlrSubtreeSpecificationLexer lexer;
053
054 private final boolean isNormalizing;
055
056
057 /**
058 * Creates a subtree specification parser.
059 */
060 public SubtreeSpecificationParser( Map<String, OidNormalizer> oidsMap )
061 {
062 StringReader in = new StringReader( "" ); // place holder for the
063 // first input
064 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
065 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
066 this.parser.init( oidsMap ); // this method MUST be called while we cannot do
067 // constructor overloading for antlr generated parser
068 this.isNormalizing = false;
069 }
070
071
072 /**
073 * Creates a normalizing subtree specification parser.
074 */
075 public SubtreeSpecificationParser( NormalizerMappingResolver resolver, Map<String, OidNormalizer> oidsMap )
076 {
077 StringReader in = new StringReader( "" ); // place holder for the
078 // first input
079 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
080 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
081 this.parser.setNormalizerMappingResolver( resolver );
082 this.parser.init( oidsMap ); // this method MUST be called while we cannot do
083 // constructor overloading for antlr generated parser
084 this.isNormalizing = true;
085 }
086
087
088 /**
089 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
090 * pair with it. param spec the specification to be parsed
091 */
092 private synchronized void reset( String spec )
093 {
094 StringReader in = new StringReader( spec + "end" ); // append end of
095 // input token
096 this.lexer.prepareNextInput( in );
097 this.parser.resetState();
098 }
099
100
101 /**
102 * Parses a subtree specification without exhausting the parser.
103 *
104 * @param spec
105 * the specification to be parsed
106 * @return the specification bean
107 * @throws ParseException
108 * if there are any recognition errors (bad syntax)
109 */
110 public synchronized SubtreeSpecification parse( String spec ) throws ParseException
111 {
112 SubtreeSpecification ss = null;
113
114 if ( spec == null || spec.trim().equals( "" ) )
115 {
116 return null;
117 }
118
119 reset( spec ); // reset and initialize the parser / lexer pair
120
121 try
122 {
123 ss = this.parser.wrapperEntryPoint();
124 }
125 catch ( TokenStreamException e )
126 {
127 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
128 throw new ParseException( msg, 0 );
129 }
130 catch ( RecognitionException e )
131 {
132 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
133 throw new ParseException( msg, e.getColumn() );
134 }
135 catch ( Exception e )
136 {
137 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
138 throw new ParseException( msg, 0 );
139 }
140
141 return ss;
142 }
143
144
145 /**
146 * Tests to see if this parser is normalizing.
147 *
148 * @return true if it normalizes false otherwise
149 */
150 public boolean isNormizing()
151 {
152 return this.isNormalizing;
153 }
154 }