1 package org.apache.torque.generator.configuration.source;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.io.ByteArrayInputStream;
23 import java.io.IOException;
24 import java.util.HashMap;
25 import java.util.Map;
26
27 import org.xml.sax.EntityResolver;
28 import org.xml.sax.InputSource;
29 import org.xml.sax.SAXException;
30
31 /**
32 * Resolves system Ids for schema files to the schema file content.
33 */
34 public class EntityReferences implements EntityResolver
35 {
36 /** All known entity references. */
37 private Map<String, byte[]> entityReferences
38 = new HashMap<String, byte[]>();
39
40 /**
41 * Adds a new entity reference.
42 *
43 * @param systemId the systemId of the entity, not null.
44 * @param content the content of the entity, not null.
45 *
46 * @throws NullPointerException if systemId or content are null.
47 * @throws IllegalArgumentException if the systemId is already defined.
48 */
49 public void addEntityReference(String systemId, byte[] content)
50 {
51 if (systemId == null)
52 {
53 throw new NullPointerException("systemId must not be null");
54 }
55 if (content == null)
56 {
57 throw new NullPointerException("content must not be null");
58 }
59 if (entityReferences.containsKey(systemId))
60 {
61 throw new IllegalArgumentException("systemId is already defined");
62 }
63 entityReferences.put(systemId, content);
64 }
65
66 /**
67 * Returns whether the given system id is known.
68 *
69 * @param systemId the system id to check.
70 *
71 * @return true if the system id can be resolved, false otherwise.
72 */
73 public boolean containsSystemId(String systemId)
74 {
75 return entityReferences.containsKey(systemId);
76 }
77
78 /**
79 * Returns a copy of the entity reference map.
80 *
81 * @return a copy of the entity reference map.
82 */
83 public Map<String, byte[]> getEntityReferences()
84 {
85 return new HashMap<String, byte[]>(entityReferences);
86 }
87
88 /**
89 * An implementation of the SAX <code>EntityResolver</code>
90 * interface to be called by the XML parser. If the systemId is known,
91 * the corresponding resource from the jar is returned.
92 * In all other cases, null is returned to indicate that the parser
93 * should open a regular connection to the systemId URI.
94 *
95 * @param publicId The public identifier of the external entity
96 * @param systemId The system identifier of the external entity
97 * @return An <code>InputSource</code> for the entity if the
98 * systemId is known, or null otherwise.
99 */
100 public InputSource resolveEntity(String publicId, String systemId)
101 throws IOException, SAXException
102 {
103
104 byte[] content = entityReferences.get(systemId);
105 if (content == null)
106 {
107 return null;
108 }
109 return new InputSource(new ByteArrayInputStream(content));
110 }
111 }