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Java > Open Source Codes > com > inversoft > verge > mvc > controller > ControllerHandler


1 /*
2  * Copyright (c) 2003, Inversoft
3  *
4  * This software is distribuable under the GNU Lesser General Public License.
5  * For more information visit gnu.org.
6  */
7 package com.inversoft.verge.mvc.controller;
8
9
10 import com.inversoft.verge.mvc.MVCException;
11 import com.inversoft.verge.mvc.MVCRequest;
12
13
14 /**
15  * <p>
16  * This interface describes how the default Inversoft MVC
17  * implementation handles the controller logic. In most
18  * cases, the controller will call some business logic, in
19  * some fashion and then change the view to show the results.
20  * Of course, the implementations will dictate how the
21  * controller portion of the MVC system works.
22  * </p>
23  *
24  * <p>
25  * This logic is abstracted in the default Inversoft MVC
26  * implementation from the {@link ControllerParser
27  * ControllerParser} interface so that it can vary depending
28  * on the request more easily. Logic default implementation
29  * uses the same parameter structure for all types of
30  * controllers. The choice of controller is dependent on
31  * a simple parameter. Therefore, the parser determines what
32  * type of controller the request will be using and then
33  * uses an implementation of this interface to call handle
34  * the controller.
35  * </p>
36  *
37  * @author Brian Pontarelli
38  * @since 2.0
39  * @version 2.0
40  */
41 public interface ControllerHandler {
42
43     /**
44      * Allows the controller implementation to set attributes on the {@link
45      * MVCRequest MVCRequest} object before any MVC processing at all happens.
46      *
47      * @param mvcRequest The MVCRequest to setup
48      * @throws com.inversoft.verge.mvc.MVCException If there were any problems during setting
49      */
50     void preExecute(MVCRequest mvcRequest) throws MVCException;
51
52     /**
53      * Handles the controller logic by calling business logic, forwarding,
54      * redirecting, or whatever implementations deem necessary.
55      *
56      * @param mvcRequest This contains the HttpServletRequest to use when
57      * calling the Controller system. It also contains the
58      * HttpServletResponse to use when calling the Controller system.
59      * Lastly This contains other controller information which can be
60      * used when calling the controller system.
61      * @return Optionally, this method can return an instance of the Result
62      * interfact that tells the ControllerParser how to handle the
63      * response, which will either to a forward or a redirect to a URL.
64      * If null is returned, the Parser assumes the result has already
65      * been handled
66      * @throws com.inversoft.verge.mvc.MVCException If there were any problems during execution
67      */
68     Result execute(MVCRequest mvcRequest) throws MVCException;
69 }
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