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.SchemaManager;
29
30 import antlr.RecognitionException;
31 import antlr.TokenStreamException;
32
33
34 /**
35 * A reusable wrapper around the antlr generated parser for an LDAP subtree
36 * specification as defined by <a href="http://www.faqs.org/rfcs/rfc3672.html">
37 * RFC 3672</a>. This class enables the reuse of the antlr parser/lexer pair
38 * without having to recreate the pair every time.
39 *
40 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
41 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
42 */
43 public class SubtreeSpecificationChecker
44 {
45 /** the antlr generated parser being wrapped */
46 private ReusableAntlrSubtreeSpecificationChecker parser;
47
48 /** the antlr generated lexer being wrapped */
49 private ReusableAntlrSubtreeSpecificationCheckerLexer lexer;
50
51
52 /**
53 * Creates a normalizing subtree specification parser.
54 */
55 public SubtreeSpecificationChecker( SchemaManager schemaManager )
56 {
57 StringReader in = new StringReader( "" ); // place holder for the
58 // first input
59 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in );
60 this.parser = new ReusableAntlrSubtreeSpecificationChecker( lexer );
61 this.parser.init( schemaManager ); // this method MUST be called while we cannot do
62 // constructor overloading for antlr generated parser
63 }
64
65
66 /**
67 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
68 * pair with it. param spec the specification to be parsed
69 */
70 private synchronized void reset( String spec )
71 {
72 StringReader in = new StringReader( spec + "end" ); // append end of
73 // input token
74 this.lexer.prepareNextInput( in );
75 this.parser.resetState();
76 }
77
78
79 /**
80 * Parses a subtree specification without exhausting the parser.
81 *
82 * @param spec
83 * the specification to be parsed
84 * @throws ParseException
85 * if there are any recognition errors (bad syntax)
86 */
87 public synchronized void parse( String spec ) throws ParseException
88 {
89 if ( spec == null || spec.trim().equals( "" ) )
90 {
91 return;
92 }
93
94 reset( spec ); // reset and initialize the parser / lexer pair
95
96 try
97 {
98 this.parser.wrapperEntryPoint();
99 }
100 catch ( TokenStreamException e )
101 {
102 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
103 throw new ParseException( msg, 0 );
104 }
105 catch ( RecognitionException e )
106 {
107 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
108 throw new ParseException( msg, e.getColumn() );
109 }
110 catch ( Exception e )
111 {
112 String msg = I18n.err( I18n.ERR_04329, spec, e.getLocalizedMessage() );
113 throw new ParseException( msg, 0 );
114 }
115 }
116
117 }