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Java > Open Source Codes > org > riotfamily > common > beans > config > HighestPrecedenceFactoryBean


1 /* ***** BEGIN LICENSE BLOCK *****
2  * Version: MPL 1.1
3  * The contents of this file are subject to the Mozilla Public License Version
4  * 1.1 (the "License"); you may not use this file except in compliance with
5  * the License. You may obtain a copy of the License at
6  * http://www.mozilla.org/MPL/
7  *
8  * Software distributed under the License is distributed on an "AS IS" basis,
9  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
10  * for the specific language governing rights and limitations under the
11  * License.
12  *
13  * The Original Code is Riot.
14  *
15  * The Initial Developer of the Original Code is
16  * Neteye GmbH.
17  * Portions created by the Initial Developer are Copyright (C) 2006
18  * the Initial Developer. All Rights Reserved.
19  *
20  * Contributor(s):
21  * Felix Gnass [fgnass at neteye dot de]
22  *
23  * ***** END LICENSE BLOCK ***** */
24 package org.riotfamily.common.beans.config;
25
26 import java.util.ArrayList JavaDoc;
27 import java.util.Collections JavaDoc;
28
29 import org.springframework.beans.factory.BeanFactoryUtils;
30 import org.springframework.beans.factory.FactoryBean;
31 import org.springframework.context.ApplicationContext;
32 import org.springframework.context.ApplicationContextAware;
33 import org.springframework.core.OrderComparator;
34 import org.springframework.core.Ordered;
35 import org.springframework.util.Assert;
36
37 /**
38  * FactoryBean that looks for all beans of a certain type and returns the one
39  * with the {@link Ordered#HIGHEST_PRECEDENCE highest precedence}.
40  *
41  * @author Felix Gnass [fgnass at neteye dot de]
42  */
43 public class HighestPrecedenceFactoryBean implements FactoryBean,
44         ApplicationContextAware {
45
46     private Class JavaDoc type;
47     
48     private ApplicationContext applicationContext;
49     
50     public void setType(Class JavaDoc type) {
51         Assert.isAssignable(Ordered.class, type, "Type must implement the " +
52                 "'org.springframework.core.Ordered' interface.");
53         
54         this.type = type;
55     }
56     
57     public void setApplicationContext(ApplicationContext applicationContext) {
58         this.applicationContext = applicationContext;
59     }
60
61     public Object JavaDoc getObject() throws Exception JavaDoc {
62         Assert.notNull(type, "A type must be specified.");
63         
64         ArrayList JavaDoc beans = new ArrayList JavaDoc(
65                 BeanFactoryUtils.beansOfTypeIncludingAncestors(
66                 applicationContext, type).values());
67         
68         Assert.notEmpty(beans, "At last one bean of type '" + type.getName()
69                 + "' must be present.");
70         
71         Collections.sort(beans, new OrderComparator());
72         return beans.get(0);
73     }
74
75     public Class JavaDoc getObjectType() {
76         return type;
77     }
78
79     public boolean isSingleton() {
80         return true;
81     }
82
83 }
84
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