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Java > Open Source Codes > org > apache > cocoon > selection > RequestAttributeSelector


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation.
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 package org.apache.cocoon.selection;
17
18 import org.apache.avalon.framework.configuration.Configurable;
19 import org.apache.avalon.framework.configuration.Configuration;
20 import org.apache.avalon.framework.configuration.ConfigurationException;
21 import org.apache.avalon.framework.logger.AbstractLogEnabled;
22 import org.apache.avalon.framework.parameters.Parameters;
23 import org.apache.avalon.framework.thread.ThreadSafe;
24 import org.apache.cocoon.environment.ObjectModelHelper;
25
26 import java.util.Map JavaDoc;
27
28 /**
29  * A <code>Selector</code> that matches a string against a configurable request
30  * attribute's string represenation.
31  *
32  * <p><b>Global and local configuration</b></p>
33  * <table border="1">
34  * <tr><td><code>attribute-name</code></td><td>String identifying the request attribute.</td></tr>
35  * </table>
36  *
37  * @author <a HREF="mailto:haul@apache.org">Christian Haul</a>
38  * @author <a HREF="mailto:sylvain@apache.org">Sylvain Wallez</a>
39  * @author <a HREF="mailto:vgritsenko@apache.org">Vadim Gritsenko</a>
40  * @version CVS $Id: RequestAttributeSelector.java 30932 2004-07-29 17:35:38Z vgritsenko $
41  */
42 public class RequestAttributeSelector extends AbstractLogEnabled
43   implements Configurable, ThreadSafe, Selector {
44
45     protected String JavaDoc defaultName;
46
47     public void configure(Configuration config) throws ConfigurationException {
48         this.defaultName = config.getChild("attribute-name").getValue(null);
49     }
50
51     public boolean select(String JavaDoc expression, Map JavaDoc objectModel, Parameters parameters) {
52         String JavaDoc name = parameters.getParameter("attribute-name", this.defaultName);
53
54         if (name == null) {
55             getLogger().warn("No attribute name given -- failing.");
56             return false;
57         }
58
59         Object JavaDoc value = ObjectModelHelper.getRequest(objectModel).getAttribute(name);
60         if (value == null) {
61             getLogger().debug("Request attribute '" + name + "' not set -- failing.");
62             return false;
63         }
64
65         return value.toString().equals(expression);
66     }
67 }
68
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