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.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; 029import org.apache.directory.api.util.Strings; 030 031import antlr.RecognitionException; 032import antlr.TokenStreamException; 033 034 035/** 036 * A reusable wrapper around the antlr generated parser for an LDAP subtree 037 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html"> 038 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair 039 * without having to recreate the pair every time. 040 * 041 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a> 042 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 043 */ 044public class SubtreeSpecificationChecker 045{ 046 /** the antlr generated parser being wrapped */ 047 private ReusableAntlrSubtreeSpecificationChecker parser; 048 049 /** the antlr generated lexer being wrapped */ 050 private ReusableAntlrSubtreeSpecificationCheckerLexer lexer; 051 052 053 /** 054 * Creates a normalizing subtree specification parser. 055 * 056 * @param schemaManager The SchemaManager 057 */ 058 public SubtreeSpecificationChecker( SchemaManager schemaManager ) 059 { 060 // place holder for the first input 061 StringReader in = new StringReader( "" ); 062 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in ); 063 this.parser = new ReusableAntlrSubtreeSpecificationChecker( 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 } 069 070 071 /** 072 * Initializes the plumbing by creating a pipe and coupling the parser/lexer 073 * pair with it. param spec the specification to be parsed 074 * 075 * @param spec The specification to parse 076 */ 077 private synchronized void reset( String spec ) 078 { 079 // append end of input token 080 StringReader in = new StringReader( spec + "end" ); 081 this.lexer.prepareNextInput( in ); 082 this.parser.resetState(); 083 } 084 085 086 /** 087 * Parses a subtree specification without exhausting the parser. 088 * 089 * @param spec the specification to be parsed 090 * @throws ParseException if there are any recognition errors (bad syntax) 091 */ 092 public synchronized void parse( String spec ) throws ParseException 093 { 094 if ( spec == null || Strings.isEmpty( spec.trim() ) ) 095 { 096 return; 097 } 098 099 // reset and initialize the parser / lexer pair 100 reset( spec ); 101 102 try 103 { 104 this.parser.wrapperEntryPoint(); 105 } 106 catch ( TokenStreamException | RecognitionException e ) 107 { 108 String msg = I18n.err( I18n.ERR_13028_SUBTREE_SPEC_PARSER_FAILURE, spec, e.getLocalizedMessage() ); 109 throw new ParseException( msg, 0 ); 110 } 111 } 112}