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
021package org.apache.directory.api.ldap.aci;
022
023
024import java.io.StringReader;
025import java.text.ParseException;
026
027import org.apache.directory.api.i18n.I18n;
028import org.apache.directory.api.ldap.model.schema.SchemaManager;
029import org.apache.directory.api.ldap.model.schema.normalizers.NameComponentNormalizer;
030import org.apache.directory.api.util.StringConstants;
031
032import antlr.RecognitionException;
033import 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 */
043public class ACIItemParser
044{
045    /** the antlr generated parser being wrapped */
046    private ReusableAntlrACIItemParser parser;
047
048    /** the antlr generated lexer being wrapped */
049    private ReusableAntlrACIItemLexer lexer;
050
051    /** The is normalizing flag. */
052    private final boolean isNormalizing;
053
054
055    /**
056     * Creates a ACIItem parser.
057     *
058     * @param schemaManager the schema manager
059     */
060    public ACIItemParser( SchemaManager schemaManager )
061    {
062        this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
063        this.parser = new ReusableAntlrACIItemParser( lexer );
064
065        // this method MUST be called while we cannot do
066        // constructor overloading for antlr generated parser
067        this.parser.init( schemaManager );
068
069        this.isNormalizing = false;
070    }
071
072
073    /**
074     * Creates a normalizing ACIItem parser.
075     *
076     * @param normalizer the normalizer
077     * @param schemaManager the schema manager
078     */
079    public ACIItemParser( NameComponentNormalizer normalizer, SchemaManager schemaManager )
080    {
081        this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
082        this.parser = new ReusableAntlrACIItemParser( lexer );
083
084        this.parser.setNormalizer( normalizer );
085        this.isNormalizing = true;
086
087        // this method MUST be called while we cannot do
088        // constructor overloading for antlr generated parser
089        this.parser.init( schemaManager );
090    }
091
092
093    /**
094     * Initializes the plumbing by creating a pipe and coupling the parser/lexer
095     * pair with it. param spec the specification to be parsed
096     */
097    private synchronized void reset( String spec )
098    {
099        StringReader in = new StringReader( spec );
100        this.lexer.prepareNextInput( in );
101        this.parser.resetState();
102    }
103
104
105    /**
106     * Parses an ACIItem without exhausting the parser.
107     * 
108     * @param spec
109     *            the specification to be parsed
110     * @return the specification bean
111     * @throws ParseException
112     *             if there are any recognition errors (bad syntax)
113     */
114    public synchronized ACIItem parse( String spec ) throws ParseException
115    {
116        ACIItem aCIItem;
117
118        if ( spec == null || StringConstants.EMPTY .equals( spec.trim() ) )
119        {
120            return null;
121        }
122
123        // reset and initialize the parser / lexer pair
124        reset( spec );
125
126        try
127        {
128            aCIItem = this.parser.wrapperEntryPoint();
129        }
130        catch ( TokenStreamException e )
131        {
132            throw new ParseException( I18n
133                .err( I18n.ERR_04004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage() ), 0 );
134        }
135        catch ( RecognitionException e )
136        {
137            throw new ParseException(
138                I18n
139                    .err( I18n.ERR_04004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage(), e.getLine(),
140                        e.getColumn() ), e.getColumn() );
141        }
142
143        return aCIItem;
144    }
145
146
147    /**
148     * Tests to see if this parser is normalizing.
149     * 
150     * @return true if it normalizes false otherwise
151     */
152    public boolean isNormizing()
153    {
154        return this.isNormalizing;
155    }
156}