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 * https://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 import org.apache.directory.api.util.Strings;
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 SubtreeSpecificationChecker
45 {
46 /** the antlr generated parser being wrapped */
47 private ReusableAntlrSubtreeSpecificationChecker parser;
48
49 /** the antlr generated lexer being wrapped */
50 private ReusableAntlrSubtreeSpecificationCheckerLexer lexer;
51
52
53 /**
54 * Creates a normalizing subtree specification parser.
55 *
56 * @param schemaManager The SchemaManager
57 */
58 public SubtreeSpecificationChecker( SchemaManager schemaManager )
59 {
60 // place holder for the first input
61 StringReader in = new StringReader( "" );
62 this.lexer = new ReusableAntlrSubtreeSpecificationCheckerLexer( in );
63 this.parser = new ReusableAntlrSubtreeSpecificationChecker( 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
70
71 /**
72 * Initializes the plumbing by creating a pipe and coupling the parser/lexer
73 * pair with it. param spec the specification to be parsed
74 *
75 * @param spec The specification to parse
76 */
77 private synchronized void reset( String spec )
78 {
79 // append end of input token
80 StringReader in = new StringReader( spec + "end" );
81 this.lexer.prepareNextInput( in );
82 this.parser.resetState();
83 }
84
85
86 /**
87 * Parses a subtree specification without exhausting the parser.
88 *
89 * @param spec the specification to be parsed
90 * @throws ParseException if there are any recognition errors (bad syntax)
91 */
92 public synchronized void parse( String spec ) throws ParseException
93 {
94 if ( spec == null || Strings.isEmpty( spec.trim() ) )
95 {
96 return;
97 }
98
99 // reset and initialize the parser / lexer pair
100 reset( spec );
101
102 try
103 {
104 this.parser.wrapperEntryPoint();
105 }
106 catch ( TokenStreamException | RecognitionException e )
107 {
108 String msg = I18n.err( I18n.ERR_13028_SUBTREE_SPEC_PARSER_FAILURE, spec, e.getLocalizedMessage() );
109 throw new ParseException( msg, 0 );
110 }
111 }
112 }