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1   /*
2    * Copyright 2006-2008 the original author or authors.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.springframework.osgi.context.support;
18  
19  import java.util.Iterator;
20  import java.util.LinkedHashMap;
21  import java.util.Map;
22  
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  import org.springframework.beans.factory.xml.NamespaceHandler;
26  import org.springframework.beans.factory.xml.NamespaceHandlerResolver;
27  import org.springframework.util.Assert;
28  
29  /**
30   * Delegated XML namespace handler resolver.
31   * 
32   * @author Costin Leau
33   * 
34   */
35  class DelegatedNamespaceHandlerResolver implements NamespaceHandlerResolver {
36  
37  	/** logger */
38  	private static final Log log = LogFactory.getLog(DelegatedNamespaceHandlerResolver.class);
39  
40  	private final Map resolvers = new LinkedHashMap(2);
41  
42  
43  	public void addNamespaceHandler(NamespaceHandlerResolver resolver, String resolverToString) {
44  		Assert.notNull(resolver);
45  		resolvers.put(resolver, resolverToString);
46  	}
47  
48  	public NamespaceHandler resolve(String namespaceUri) {
49  		boolean trace = log.isTraceEnabled();
50  
51  		for (Iterator iterator = resolvers.entrySet().iterator(); iterator.hasNext();) {
52  			Map.Entry entry = (Map.Entry) iterator.next();
53  			NamespaceHandlerResolver handlerResolver = (NamespaceHandlerResolver) entry.getKey();
54  			if (trace)
55  				log.trace("Trying to resolve namespace [" + namespaceUri + "] through resolver " + entry.getValue());
56  			NamespaceHandler handler = handlerResolver.resolve(namespaceUri);
57  
58  			String resolvedMsg = (handler != null ? "" : "not ");
59  			if (trace)
60  				log.trace("Namespace [" + namespaceUri + "] was " + resolvedMsg + "resolved through handler resolver "
61  						+ entry.getValue());
62  
63  			if (handler != null) {
64  				return handler;
65  			}
66  
67  		}
68  		return null;
69  	}
70  }