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 *    https://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.util.StringConstants;
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 ACIItemChecker
043{
044    /** the antlr generated parser being wrapped */
045    private ReusableAntlrACIItemParser checker;
046
047    /** the antlr generated lexer being wrapped */
048    private ReusableAntlrACIItemLexer lexer;
049
050
051    /**
052     * Creates a ACIItem parser.
053     *
054     * @param schemaManager the schema manager
055     */
056    public ACIItemChecker( SchemaManager schemaManager )
057    {
058        this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
059        this.checker = new ReusableAntlrACIItemParser( lexer );
060        this.checker.init( schemaManager );
061    }
062
063
064    /**
065     * Initializes the plumbing by creating a pipe and coupling the parser/lexer
066     * pair with it. param spec the specification to be parsed
067     * 
068     * @param spec The part to parse
069     */
070    private synchronized void reset( String spec )
071    {
072        StringReader in = new StringReader( spec );
073        this.lexer.prepareNextInput( in );
074        this.checker.resetState();
075    }
076
077
078    /**
079     * Parses an ACIItem without exhausting the parser.
080     * 
081     * @param spec
082     *            the specification to be parsed
083     * @throws ParseException
084     *             if there are any recognition errors (bad syntax)
085     */
086    public synchronized void parse( String spec ) throws ParseException
087    {
088        if ( spec == null || StringConstants.EMPTY.equals( spec.trim() ) )
089        {
090            return;
091        }
092
093        // reset and initialize the parser / lexer pair
094        reset( spec );
095
096        try
097        {
098            this.checker.wrapperEntryPoint();
099        }
100        catch ( TokenStreamException e )
101        {
102            throw new ParseException( I18n
103                .err( I18n.ERR_07004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage() ), 0 );
104        }
105        catch ( RecognitionException e )
106        {
107            throw new ParseException( I18n
108                .err( I18n.ERR_07004_PARSER_FAILURE_ACI_ITEM, spec, e.getLocalizedMessage() ), e.getColumn() );
109        }
110    }
111
112}