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
030 import antlr.RecognitionException;
031 import antlr.TokenStreamException;
032
033
034 /**
035 * A reusable wrapper around the antlr generated parser for an LDAP subtree
036 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html">
037 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair
038 * without having to recreate the pair every time.
039 *
040 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
041 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
042 * @version $Rev: 437007 $
043 */
044 public class SubtreeSpecificationChecker
045 {
046 /** the antlr generated parser being wrapped */
047 private ReusableAntlrSubtreeSpecificationChecker parser;
048
049 /** the antlr generated lexer being wrapped */
050 private ReusableAntlrSubtreeSpecificationCheckerLexer lexer;
051
052
053 /**
054 * Creates a subtree specification parser.
055 */
056 public SubtreeSpecificationChecker( Map oidsMap )
057 {
058 StringReader in = new StringReader( "" ); // place holder for the
059 // first input
060 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in );
061 this.parser = new ReusableAntlrSubtreeSpecificationChecker( lexer );
062 this.parser.init(); // this method MUST be called while we cannot do
063 // constructor overloading for antlr generated parser
064 }
065
066
067 /**
068 * Creates a normalizing subtree specification parser.
069 */
070 public SubtreeSpecificationChecker()
071 {
072 StringReader in = new StringReader( "" ); // place holder for the
073 // first input
074 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in );
075 this.parser = new ReusableAntlrSubtreeSpecificationChecker( lexer );
076 this.parser.init(); // this method MUST be called while we cannot do
077 // constructor overloading for antlr generated parser
078 }
079
080
081 /**
082 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
083 * pair with it. param spec the specification to be parsed
084 */
085 private synchronized void reset( String spec )
086 {
087 StringReader in = new StringReader( spec + "end" ); // append end of
088 // input token
089 this.lexer.prepareNextInput( in );
090 this.parser.resetState();
091 }
092
093
094 /**
095 * Parses a subtree specification without exhausting the parser.
096 *
097 * @param spec
098 * the specification to be parsed
099 * @throws ParseException
100 * if there are any recognition errors (bad syntax)
101 */
102 public synchronized void parse( String spec ) throws ParseException
103 {
104 if ( spec == null || spec.trim().equals( "" ) )
105 {
106 return;
107 }
108
109 reset( spec ); // reset and initialize the parser / lexer pair
110
111 try
112 {
113 this.parser.wrapperEntryPoint();
114 }
115 catch ( TokenStreamException e )
116 {
117 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
118 throw new ParseException( msg, 0 );
119 }
120 catch ( RecognitionException e )
121 {
122 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
123 throw new ParseException( msg, e.getColumn() );
124 }
125 catch ( Exception e )
126 {
127 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
128 throw new ParseException( msg, 0 );
129 }
130 }
131
132 }