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 public SubtreeSpecificationParser( SchemaManager schemaManager )
59 {
60 StringReader in = new StringReader( "" ); // place holder for the
61 // first input
62 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
63 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
64 this.parser.init( schemaManager ); // this method MUST be called while we cannot do
65 // constructor overloading for antlr generated parser
66 this.isNormalizing = false;
67 }
68
69
70 /**
71 * Creates a normalizing subtree specification parser.
72 */
73 public SubtreeSpecificationParser( @SuppressWarnings("rawtypes") NormalizerMappingResolver resolver,
74 SchemaManager schemaManager )
75 {
76 StringReader in = new StringReader( "" ); // place holder for the
77 // first input
78 this.lexer = new ReusableAntlrSubtreeSpecificationLexer( in );
79 this.parser = new ReusableAntlrSubtreeSpecificationParser( lexer );
80 this.parser.setNormalizerMappingResolver( resolver );
81 this.parser.init( schemaManager ); // this method MUST be called while we cannot do
82 // constructor overloading for antlr generated parser
83 this.isNormalizing = true;
84 }
85
86
87 /**
88 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
89 * pair with it. param spec the specification to be parsed
90 */
91 private synchronized void reset( String spec )
92 {
93 StringReader in = new StringReader( spec + "end" ); // append end of
94 // input token
95 this.lexer.prepareNextInput( in );
96 this.parser.resetState();
97 }
98
99
100 /**
101 * Parses a subtree specification without exhausting the parser.
102 *
103 * @param spec
104 * the specification to be parsed
105 * @return the specification bean
106 * @throws ParseException
107 * if there are any recognition errors (bad syntax)
108 */
109 public synchronized SubtreeSpecification parse( String spec ) throws ParseException
110 {
111 SubtreeSpecification ss = null;
112
113 if ( spec == null || spec.trim().equals( "" ) )
114 {
115 return null;
116 }
117
118 reset( spec ); // reset and initialize the parser / lexer pair
119
120 try
121 {
122 ss = this.parser.wrapperEntryPoint();
123 }
124 catch ( TokenStreamException e )
125 {
126 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
127 throw new ParseException( msg, 0 );
128 }
129 catch ( RecognitionException e )
130 {
131 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
132 throw new ParseException( msg, e.getColumn() );
133 }
134 catch ( Exception e )
135 {
136 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
137 throw new ParseException( msg, 0 );
138 }
139
140 return ss;
141 }
142
143
144 /**
145 * Tests to see if this parser is normalizing.
146 *
147 * @return true if it normalizes false otherwise
148 */
149 public boolean isNormizing()
150 {
151 return this.isNormalizing;
152 }
153 }