1 package org.apache.commons.digester3.plugins.strategies;
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 static org.apache.commons.digester3.binder.DigesterLoader.newLoader;
23
24 import java.io.ByteArrayInputStream;
25 import java.io.ByteArrayOutputStream;
26 import java.io.IOException;
27 import java.io.InputStream;
28
29 import org.apache.commons.digester3.Digester;
30 import org.apache.commons.digester3.plugins.PluginException;
31 import org.apache.commons.digester3.plugins.RuleLoader;
32 import org.apache.commons.digester3.xmlrules.FromXmlRulesModule;
33 import org.apache.commons.logging.Log;
34 import org.xml.sax.InputSource;
35
36 /**
37 * A rule-finding algorithm which loads an xmlplugins-format file.
38 * <p>
39 * Note that the "include" feature of xmlrules is not supported.
40 *
41 * @since 1.6
42 */
43 public class LoaderFromStream
44 extends RuleLoader
45 {
46
47 private final byte[] input;
48
49 /**
50 * The contents of the input stream are loaded into memory, and cached for later use.
51 * <p>
52 * The caller is responsible for closing the input stream after this method has returned.
53 *
54 * @param s the input stream has to be loaded into memory
55 * @throws Exception if any error occurs while reading the input stream
56 */
57 public LoaderFromStream( InputStream s )
58 throws Exception
59 {
60 try
61 {
62 ByteArrayOutputStream baos = new ByteArrayOutputStream();
63 byte[] buf = new byte[256];
64 for ( ;; )
65 {
66 int i = s.read( buf );
67 if ( i == -1 )
68 {
69 break;
70 }
71 baos.write( buf, 0, i );
72 }
73 input = baos.toByteArray();
74 }
75 finally
76 {
77 try
78 {
79 if ( s != null )
80 {
81 s.close();
82 }
83 }
84 catch ( IOException e )
85 {
86 // close quietly
87 }
88 }
89 }
90
91 /**
92 * {@inheritDoc}
93 */
94 @Override
95 public void addRules( final Digester d, final String path )
96 throws PluginException
97 {
98 Log log = d.getLogger();
99 boolean debug = log.isDebugEnabled();
100 if ( debug )
101 {
102 log.debug( "LoaderFromStream: loading rules for plugin at path [" + path + "]" );
103 }
104
105 // Note that this input-source doesn't have any idea of its
106 // system id, so it has no way of resolving relative URLs
107 // such as the "include" feature of xmlrules. This is ok,
108 // because that doesn't work well with our approach of
109 // caching the input data in memory anyway.
110
111 final InputSource source = new InputSource( new ByteArrayInputStream( input ) );
112 newLoader( new FromXmlRulesModule()
113 {
114
115 @Override
116 protected void loadRules()
117 {
118 useRootPath( path );
119 loadXMLRules( source );
120 }
121
122 } ).createRuleSet().addRuleInstances( d );
123 }
124
125 }