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.model.subtree;
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.NormalizerMappingResolver;
29 import org.apache.directory.api.ldap.model.schema.SchemaManager;
30
31 import antlr.RecognitionException;
32 import antlr.TokenStreamException;
33
34
35 /**
36 * A reusable wrapper around the antlr generated parser for an LDAP subtree
37 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html">
38 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair
39 * without having to recreate the pair every time.
40 *
41 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
42 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
43 */
44 public class SubtreeSpecificationParser
45 {
46 /** the antlr generated parser being wrapped */
47 private ReusableAntlrSubtreeSpecificationParser parser;
48
49 /** the antlr generated lexer being wrapped */
50 private ReusableAntlrSubtreeSpecificationLexer lexer;
51
52 private final boolean isNormalizing;
53
54
55 /**
56 * Creates a subtree specification parser.
57 *
58 * @param schemaManager The SchemaManager
59 */
60 public SubtreeSpecificationParser( SchemaManager schemaManager )
61 {
62 // place holder for the first input
63 StringReader in = new StringReader( "" );
64 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
65 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
66 // this method MUST be called while we cannot do
67 // constructor overloading for antlr generated parser
68 this.parser.init( schemaManager );
69 this.isNormalizing = false;
70 }
71
72
73 /**
74 * Creates a normalizing subtree specification parser.
75 *
76 * @param resolver The resolver to use
77 * @param schemaManager The SchemaManager
78 */
79 public SubtreeSpecificationParser( @SuppressWarnings("rawtypes") NormalizerMappingResolver resolver,
80 SchemaManager schemaManager )
81 {
82 // place holder for the first input
83 StringReader in = new StringReader( "" );
84 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
85 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
86 this.parser.setNormalizerMappingResolver( resolver );
87 // this method MUST be called while we cannot do
88 // constructor overloading for antlr generated parser
89 this.parser.init( schemaManager );
90 this.isNormalizing = true;
91 }
92
93
94 /**
95 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
96 * pair with it. param spec the specification to be parsed
97 */
98 private synchronized void reset( String spec )
99 {
100 // append end of input token
101 StringReader in = new StringReader( spec + "end" );
102 this.lexer.prepareNextInput( in );
103 this.parser.resetState();
104 }
105
106
107 /**
108 * Parses a subtree specification without exhausting the parser.
109 *
110 * @param spec
111 * the specification to be parsed
112 * @return the specification bean
113 * @throws ParseException
114 * if there are any recognition errors (bad syntax)
115 */
116 public synchronized SubtreeSpecification parse( String spec ) throws ParseException
117 {
118 SubtreeSpecification ss;
119
120 if ( ( spec == null ) || ( spec.trim().length() == 0 ) )
121 {
122 return null;
123 }
124
125 // reset and initialize the parser / lexer pair
126 reset( spec );
127
128 try
129 {
130 ss = this.parser.wrapperEntryPoint();
131 }
132 catch ( TokenStreamException | RecognitionException e )
133 {
134 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
135 throw new ParseException( msg, 0 );
136 }
137
138 return ss;
139 }
140
141
142 /**
143 * Tests to see if this parser is normalizing.
144 *
145 * @return true if it normalizes false otherwise
146 */
147 public boolean isNormizing()
148 {
149 return this.isNormalizing;
150 }
151 }