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.trigger;
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.Normalizer;
29 import org.apache.directory.api.ldap.model.schema.NormalizerMappingResolver;
30
31 import antlr.RecognitionException;
32 import antlr.TokenStreamException;
33
34
35 /**
36 * A reusable wrapper around the ANTLR generated parser for a
37 * TriggerSpecification. This class enables the reuse of the antlr parser/lexer
38 * pair without having to recreate them every time.
39 *
40 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
41 */
42 public class TriggerSpecificationParser
43 {
44 /** the antlr generated parser being wrapped */
45 private ReusableAntlrTriggerSpecificationParser parser;
46
47 /** the antlr generated lexer being wrapped */
48 private ReusableAntlrTriggerSpecificationLexer lexer;
49
50 private final boolean isNormalizing;
51
52
53 /**
54 * Creates a TriggerSpecification parser.
55 */
56 public TriggerSpecificationParser()
57 {
58 this.lexer = new ReusableAntlrTriggerSpecificationLexer( new StringReader( "" ) );
59 this.parser = new ReusableAntlrTriggerSpecificationParser( lexer );
60
61 this.parser.init(); // this method MUST be called while we cannot do
62 // constructor overloading for antlr generated parser
63 this.isNormalizing = false;
64 }
65
66
67 /**
68 * Creates a normalizing TriggerSpecification parser.
69 *
70 * @param resolver the resolver
71 */
72 public TriggerSpecificationParser( NormalizerMappingResolver<Normalizer> resolver )
73 {
74 this.lexer = new ReusableAntlrTriggerSpecificationLexer( new StringReader( "" ) );
75 this.parser = new ReusableAntlrTriggerSpecificationParser( lexer );
76
77 this.parser.setNormalizerMappingResolver( resolver );
78 this.parser.init(); // this method MUST be called while we cannot do
79 // constructor overloading for ANTLR generated parser
80 this.isNormalizing = true;
81 }
82
83
84 /**
85 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
86 * pair with it.
87 *
88 * @param
89 * spec the specification to be parsed
90 */
91 private synchronized void reset( String spec )
92 {
93 StringReader in = new StringReader( spec );
94 this.lexer.prepareNextInput( in );
95 this.parser.resetState();
96 }
97
98
99 /**
100 * Parses an TriggerSpecification without exhausting the parser.
101 *
102 * @param spec
103 * the specification to be parsed
104 * @return the specification bean
105 * @throws ParseException
106 * if there are any recognition errors (bad syntax)
107 */
108 public synchronized TriggerSpecification parse( String spec ) throws ParseException
109 {
110 TriggerSpecification triggerSpecification = null;
111
112 if ( spec == null || spec.trim().equals( "" ) )
113 {
114 return null;
115 }
116
117 reset( spec ); // reset and initialize the parser / lexer pair
118
119 try
120 {
121 triggerSpecification = this.parser.wrapperEntryPoint();
122 }
123 catch ( TokenStreamException e )
124 {
125 String msg = I18n.err( I18n.ERR_04333, spec, e.getLocalizedMessage() );
126 throw new ParseException( msg, 0 );
127 }
128 catch ( RecognitionException e )
129 {
130 String msg = I18n.err( I18n.ERR_04333, spec, e.getLocalizedMessage() );
131 throw new ParseException( msg, e.getColumn() );
132 }
133
134 return triggerSpecification;
135
136 }
137
138
139 /**
140 * Tests to see if this parser is normalizing.
141 *
142 * @return true if it normalizes false otherwise
143 */
144 public boolean isNormizing()
145 {
146 return this.isNormalizing;
147 }
148 }