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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  
21  package org.apache.directory.api.ldap.aci;
22  
23  
24  import java.io.StringReader;
25  import java.text.ParseException;
26  
27  import org.apache.directory.api.i18n.I18n;
28  import org.apache.directory.api.ldap.model.schema.SchemaManager;
29  import org.apache.directory.api.ldap.model.schema.normalizers.NameComponentNormalizer;
30  import org.apache.directory.api.util.StringConstants;
31  
32  import antlr.RecognitionException;
33  import antlr.TokenStreamException;
34  
35  
36  /**
37   * A reusable wrapper around the antlr generated parser for an ACIItem as
38   * defined by X.501. This class enables the reuse of the antlr parser/lexer pair
39   * without having to recreate them every time.
40   * 
41   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
42   */
43  public class ACIItemParser
44  {
45      /** the antlr generated parser being wrapped */
46      private ReusableAntlrACIItemParser parser;
47  
48      /** the antlr generated lexer being wrapped */
49      private ReusableAntlrACIItemLexer lexer;
50  
51      /** The is normalizing flag. */
52      private final boolean isNormalizing;
53  
54  
55      /**
56       * Creates a ACIItem parser.
57       *
58       * @param schemaManager the schema manager
59       */
60      public ACIItemParser( SchemaManager schemaManager )
61      {
62          this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
63          this.parser = new ReusableAntlrACIItemParser( lexer );
64  
65          // this method MUST be called while we cannot do
66          // constructor overloading for antlr generated parser
67          this.parser.init( schemaManager );
68  
69          this.isNormalizing = false;
70      }
71  
72  
73      /**
74       * Creates a normalizing ACIItem parser.
75       *
76       * @param normalizer the normalizer
77       * @param schemaManager the schema manager
78       */
79      public ACIItemParser( NameComponentNormalizer normalizer, SchemaManager schemaManager )
80      {
81          this.lexer = new ReusableAntlrACIItemLexer( new StringReader( "" ) );
82          this.parser = new ReusableAntlrACIItemParser( lexer );
83  
84          this.parser.setNormalizer( normalizer );
85          this.isNormalizing = true;
86  
87          // this method MUST be called while we cannot do
88          // constructor overloading for antlr generated parser
89          this.parser.init( schemaManager );
90      }
91  
92  
93      /**
94       * Initializes the plumbing by creating a pipe and coupling the parser/lexer
95       * pair with it. param spec the specification to be parsed
96       */
97      private synchronized void reset( String spec )
98      {
99          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 }