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Java > Open Source Codes > org > apache > turbine > ValveContext


1 package org.apache.turbine;
2
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2001 The Apache Software Foundation. All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  * if any, must include the following acknowledgment:
23  * "This product includes software developed by the
24  * Apache Software Foundation (http://www.apache.org/)."
25  * Alternately, this acknowledgment may appear in the software itself,
26  * if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation" and
29  * "Apache Turbine" must not be used to endorse or promote products
30  * derived from this software without prior written permission. For
31  * written permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache",
34  * "Apache Turbine", nor may "Apache" appear in their name, without
35  * prior written permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation. For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  */
56
57 import java.io.IOException JavaDoc;
58
59 /**
60  * <p>A <b>ValveContext</b> is the mechanism by which a Valve can trigger the
61  * execution of the next Valve in a Pipeline, without having to know anything
62  * about the internal implementation mechanisms. An instance of a class
63  * implementing this interface is passed as a parameter to the
64  * <code>Valve.invoke()</code> method of each executed Valve.</p>
65  *
66  * <p><strong>IMPLEMENTATION NOTE</strong>: It is up to the implementation of
67  * ValveContext to ensure that simultaneous requests being processed (by
68  * separate threads) through the same Pipeline do not interfere with each
69  * other's flow of control.</p>
70  *
71  * @author Craig R. McClanahan
72  * @author Gunnar Rjnning
73  * @author Peter Donald
74  * @author <a HREF="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
75  * @version $Revision: 1.2 $ $Date: 2001/12/29 22:52:09 $
76  */
77 public interface ValveContext
78 {
79     /**
80      * <p>Cause the <code>invoke()</code> method of the next Valve
81      * that is part of the Pipeline currently being processed (if any)
82      * to be executed, passing on the specified request and response
83      * objects plus this <code>ValveContext</code> instance.
84      * Exceptions thrown by a subsequently executed Valve will be
85      * passed on to our caller.</p>
86      *
87      * <p>If there are no more Valves to be executed, execution of
88      * this method will result in a no op.</p>
89      *
90      * @param data The run-time information, including the servlet
91      * request and response we are processing.
92      *
93      * @exception IOException Thrown by a subsequent Valve.
94      * @exception TurbineException Thrown by a subsequent Valve.
95      * @exception TurbineException No further Valves configured in the
96      * Pipeline currently being processed.
97      */
98     public void invokeNext(RunData data)
99         throws IOException JavaDoc, TurbineException;
100 }
101
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