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.aci;
022
023
024 import java.io.StringReader;
025 import java.text.ParseException;
026
027 import org.apache.directory.shared.i18n.I18n;
028
029 import antlr.RecognitionException;
030 import antlr.TokenStreamException;
031
032
033 /**
034 * A reusable wrapper around the antlr generated parser for an ACIItem as
035 * defined by X.501. This class enables the reuse of the antlr parser/lexer pair
036 * without having to recreate them every time.
037 *
038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
039 * @version $Rev: 437007 $
040 */
041 public class ACIItemChecker
042 {
043 /** the antlr generated parser being wrapped */
044 private ReusableAntlrACIItemParser checker;
045
046 /** the antlr generated lexer being wrapped */
047 private ReusableAntlrACIItemLexer lexer;
048
049 private final boolean isNormalizing;
050
051
052 /**
053 * Creates a ACIItem parser.
054 */
055 public ACIItemChecker()
056 {
057 this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
058 this.checker = new ReusableAntlrACIItemParser( lexer );
059 this.isNormalizing = false;
060 }
061
062
063 /**
064 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
065 * pair with it. param spec the specification to be parsed
066 */
067 private synchronized void reset( String spec )
068 {
069 StringReader in = new StringReader( spec );
070 this.lexer.prepareNextInput( in );
071 this.checker.resetState();
072 }
073
074
075 /**
076 * Parses an ACIItem without exhausting the parser.
077 *
078 * @param spec
079 * the specification to be parsed
080 * @return the specification bean
081 * @throws ParseException
082 * if there are any recognition errors (bad syntax)
083 */
084 public synchronized void parse( String spec ) throws ParseException
085 {
086 if ( spec == null || spec.trim().equals( "" ) )
087 {
088 return;
089 }
090
091 reset( spec ); // reset and initialize the parser / lexer pair
092
093 try
094 {
095 this.checker.wrapperEntryPoint();
096 }
097 catch ( TokenStreamException e )
098 {
099 throw new ParseException( I18n.err( I18n.ERR_00004, spec, e.getLocalizedMessage() ), 0 );
100 }
101 catch ( RecognitionException e )
102 {
103 throw new ParseException( I18n.err( I18n.ERR_00004, spec, e.getLocalizedMessage() ), e.getColumn() );
104 }
105
106 return;
107 }
108
109
110 /**
111 * Tests to see if this parser is normalizing.
112 *
113 * @return true if it normalizes false otherwise
114 */
115 public boolean isNormizing()
116 {
117 return this.isNormalizing;
118 }
119 }