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;
030
031import antlr.RecognitionException;
032import antlr.TokenStreamException;
033
034
035/**
036 * A reusable wrapper around the antlr generated parser for an ACIItem as
037 * defined by X.501. This class enables the reuse of the antlr parser/lexer pair
038 * without having to recreate them every time.
039 * 
040 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
041 */
042public class ACIItemParser
043{
044    /** the antlr generated parser being wrapped */
045    private ReusableAntlrACIItemParser parser;
046
047    /** the antlr generated lexer being wrapped */
048    private ReusableAntlrACIItemLexer lexer;
049
050    /** The is normalizing flag. */
051    private final boolean isNormalizing;
052
053
054    /**
055     * Creates a ACIItem parser.
056     *
057     * @param schemaManager the schema manager
058     */
059    public ACIItemParser( SchemaManager schemaManager )
060    {
061        this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
062        this.parser = new ReusableAntlrACIItemParser( lexer );
063
064        // this method MUST be called while we cannot do
065        // constructor overloading for antlr generated parser
066        this.parser.init( schemaManager );
067
068        this.isNormalizing = false;
069    }
070
071
072    /**
073     * Creates a normalizing ACIItem parser.
074     *
075     * @param normalizer the normalizer
076     * @param schemaManager the schema manager
077     */
078    public ACIItemParser( NameComponentNormalizer normalizer, SchemaManager schemaManager )
079    {
080        this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
081        this.parser = new ReusableAntlrACIItemParser( lexer );
082
083        this.parser.setNormalizer( normalizer );
084        this.isNormalizing = true;
085
086        // this method MUST be called while we cannot do
087        // constructor overloading for antlr generated parser
088        this.parser.init( schemaManager );
089    }
090
091
092    /**
093     * Initializes the plumbing by creating a pipe and coupling the parser/lexer
094     * pair with it. param spec the specification to be parsed
095     */
096    private synchronized void reset( String spec )
097    {
098        StringReader in = new StringReader( spec );
099        this.lexer.prepareNextInput( in );
100        this.parser.resetState();
101    }
102
103
104    /**
105     * Parses an ACIItem without exhausting the parser.
106     * 
107     * @param spec
108     *            the specification to be parsed
109     * @return the specification bean
110     * @throws ParseException
111     *             if there are any recognition errors (bad syntax)
112     */
113    public synchronized ACIItem parse( String spec ) throws ParseException
114    {
115        ACIItem aCIItem = null;
116
117        if ( spec == null || spec.trim().equals( "" ) )
118        {
119            return null;
120        }
121
122        reset( spec ); // reset and initialize the parser / lexer pair
123
124        try
125        {
126            aCIItem = this.parser.wrapperEntryPoint();
127        }
128        catch ( TokenStreamException e )
129        {
130            throw new ParseException( I18n
131                .err( I18n.ERR_04004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage() ), 0 );
132        }
133        catch ( RecognitionException e )
134        {
135            throw new ParseException(
136                I18n
137                    .err( I18n.ERR_04004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage(), e.getLine(),
138                        e.getColumn() ), e.getColumn() );
139        }
140
141        return aCIItem;
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}