001 package org.apache.commons.digester3.plugins.strategies;
002
003 /*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements. See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership. The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License. You may obtain a copy of the License at
011 *
012 * http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied. See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022 import static org.apache.commons.digester3.binder.DigesterLoader.newLoader;
023
024 import java.io.ByteArrayInputStream;
025 import java.io.ByteArrayOutputStream;
026 import java.io.IOException;
027 import java.io.InputStream;
028
029 import org.apache.commons.digester3.Digester;
030 import org.apache.commons.digester3.plugins.PluginException;
031 import org.apache.commons.digester3.plugins.RuleLoader;
032 import org.apache.commons.digester3.xmlrules.FromXmlRulesModule;
033 import org.apache.commons.logging.Log;
034 import org.xml.sax.InputSource;
035
036 /**
037 * A rule-finding algorithm which loads an xmlplugins-format file.
038 * <p>
039 * Note that the "include" feature of xmlrules is not supported.
040 *
041 * @since 1.6
042 */
043 public class LoaderFromStream
044 extends RuleLoader
045 {
046
047 private final byte[] input;
048
049 /**
050 * The contents of the input stream are loaded into memory, and cached for later use.
051 * <p>
052 * The caller is responsible for closing the input stream after this method has returned.
053 *
054 * @param s the input stream has to be loaded into memory
055 * @throws Exception if any error occurs while reading the input stream
056 */
057 public LoaderFromStream( InputStream s )
058 throws Exception
059 {
060 try
061 {
062 ByteArrayOutputStream baos = new ByteArrayOutputStream();
063 byte[] buf = new byte[256];
064 for ( ;; )
065 {
066 int i = s.read( buf );
067 if ( i == -1 )
068 {
069 break;
070 }
071 baos.write( buf, 0, i );
072 }
073 input = baos.toByteArray();
074 }
075 finally
076 {
077 try
078 {
079 if ( s != null )
080 {
081 s.close();
082 }
083 }
084 catch ( IOException e )
085 {
086 // close quietly
087 }
088 }
089 }
090
091 /**
092 * {@inheritDoc}
093 */
094 @Override
095 public void addRules( final Digester d, final String path )
096 throws PluginException
097 {
098 Log log = d.getLogger();
099 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 }