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    import java.util.Map;
027    
028    import org.apache.directory.shared.i18n.I18n;
029    import org.apache.directory.shared.ldap.name.NameComponentNormalizer;
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 ACIItem as
038     * defined by X.501. This class enables the reuse of the antlr parser/lexer pair
039     * without having to recreate them every time.
040     * 
041     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
042     * @version $Rev: 928938 $
043     */
044    public class ACIItemParser
045    {
046        /** the antlr generated parser being wrapped */
047        private ReusableAntlrACIItemParser parser;
048    
049        /** the antlr generated lexer being wrapped */
050        private ReusableAntlrACIItemLexer lexer;
051    
052        private final boolean isNormalizing;
053    
054    
055        /**
056         * Creates a ACIItem parser.
057         */
058        public ACIItemParser( Map<String, OidNormalizer> oidsMap )
059        {
060            this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
061            this.parser = new ReusableAntlrACIItemParser( lexer );
062    
063            this.parser.init( oidsMap ); // this method MUST be called while we cannot do
064            // constructor overloading for antlr generated parser
065            this.isNormalizing = false;
066        }
067    
068    
069        /**
070         * Creates a normalizing ACIItem parser.
071         */
072        public ACIItemParser( NameComponentNormalizer normalizer, Map<String, OidNormalizer> oidsMap )
073        {
074            this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
075            this.parser = new ReusableAntlrACIItemParser( lexer );
076    
077            this.parser.setNormalizer( normalizer );
078            this.parser.init( oidsMap ); // this method MUST be called while we cannot do
079            // constructor overloading for antlr generated parser
080            this.isNormalizing = true;
081        }
082    
083    
084        /**
085         * Initializes the plumbing by creating a pipe and coupling the parser/lexer
086         * pair with it. param spec the specification to be parsed
087         */
088        private synchronized void reset( String spec )
089        {
090            StringReader in = new StringReader( spec );
091            this.lexer.prepareNextInput( in );
092            this.parser.resetState();
093        }
094    
095    
096        /**
097         * Parses an ACIItem without exhausting the parser.
098         * 
099         * @param spec
100         *            the specification to be parsed
101         * @return the specification bean
102         * @throws ParseException
103         *             if there are any recognition errors (bad syntax)
104         */
105        public synchronized ACIItem parse( String spec ) throws ParseException
106        {
107            ACIItem aCIItem = null;
108    
109            if ( spec == null || spec.trim().equals( "" ) )
110            {
111                return null;
112            }
113    
114            reset( spec ); // reset and initialize the parser / lexer pair
115    
116            try
117            {
118                aCIItem = this.parser.wrapperEntryPoint();
119            }
120            catch ( TokenStreamException e )
121            {
122                throw new ParseException( I18n.err( I18n.ERR_00004, spec, e.getLocalizedMessage() ), 0 );
123            }
124            catch ( RecognitionException e )
125            {
126                throw new ParseException( I18n.err( I18n.ERR_00004, spec, e.getLocalizedMessage() ), e.getColumn() );
127            }
128    
129            return aCIItem;
130        }
131    
132    
133        /**
134         * Tests to see if this parser is normalizing.
135         * 
136         * @return true if it normalizes false otherwise
137         */
138        public boolean isNormizing()
139        {
140            return this.isNormalizing;
141        }
142    }