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.model.subtree; 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; 029 030import antlr.RecognitionException; 031import antlr.TokenStreamException; 032 033 034/** 035 * A reusable wrapper around the antlr generated parser for an LDAP subtree 036 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html"> 037 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair 038 * without having to recreate the pair every time. 039 * 040 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a> 041 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 042 */ 043public class SubtreeSpecificationChecker 044{ 045 /** the antlr generated parser being wrapped */ 046 private ReusableAntlrSubtreeSpecificationChecker parser; 047 048 /** the antlr generated lexer being wrapped */ 049 private ReusableAntlrSubtreeSpecificationCheckerLexer lexer; 050 051 052 /** 053 * Creates a normalizing subtree specification parser. 054 * 055 * @param schemaManager The SchemaManager 056 */ 057 public SubtreeSpecificationChecker( SchemaManager schemaManager ) 058 { 059 // place holder for the first input 060 StringReader in = new StringReader( "" ); 061 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in ); 062 this.parser = new ReusableAntlrSubtreeSpecificationChecker( 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 } 068 069 070 /** 071 * Initializes the plumbing by creating a pipe and coupling the parser/lexer 072 * pair with it. param spec the specification to be parsed 073 * 074 * @param spec The specification to parse 075 */ 076 private synchronized void reset( String spec ) 077 { 078 // append end of input token 079 StringReader in = new StringReader( spec + "end" ); 080 this.lexer.prepareNextInput( in ); 081 this.parser.resetState(); 082 } 083 084 085 /** 086 * Parses a subtree specification without exhausting the parser. 087 * 088 * @param spec the specification to be parsed 089 * @throws ParseException if there are any recognition errors (bad syntax) 090 */ 091 public synchronized void parse( String spec ) throws ParseException 092 { 093 if ( ( spec == null ) || ( spec.trim().length() == 0 ) ) 094 { 095 return; 096 } 097 098 // reset and initialize the parser / lexer pair 099 reset( spec ); 100 101 try 102 { 103 this.parser.wrapperEntryPoint(); 104 } 105 catch ( TokenStreamException | RecognitionException e ) 106 { 107 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() ); 108 throw new ParseException( msg, 0 ); 109 } 110 } 111}