01: /*
02: * Copyright 2002-2005 the original author or authors.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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.web.servlet.mvc.throwaway;
18:
19: import org.springframework.web.servlet.ModelAndView;
20:
21: /**
22: * ThrowawayController is an alternative to Spring's default Controller interface,
23: * for executable per-request command instances that are not aware of the Servlet API.
24: * In contrast to Controller, implementing beans are not supposed to be defined as
25: * Servlet/Struts-style singletons that process a HttpServletRequest but rather as
26: * WebWork/Maverick-style prototypes that get populated with request parameters,
27: * executed to determine a view, and thrown away afterwards.
28: *
29: * <p>The main advantage of this controller programming model is that controllers
30: * are testable without HttpServletRequest/HttpServletResponse mocks, just like
31: * WebWork actions. They are still web UI workflow controllers: Spring does not
32: * aim for the arguably hard-to-achieve reusability of such controllers in non-web
33: * environments, as XWork (the generic command framework from WebWork2) does
34: * but just for ease of testing.
35: *
36: * <p>A ThrowawayController differs from the command notion of Base- or
37: * AbstractCommandController in that a ThrowawayController is an <i>executable</i>
38: * command that contains workflow logic to determine the next view to render,
39: * while BaseCommandController treats commands as plain parameter holders.
40: *
41: * <p>If binding request parameters to this controller fails, a fatal BindException
42: * will be thrown.
43: *
44: * <p>If you need access to the HttpServletRequest and/or HttpServletResponse,
45: * consider implementing Controller or deriving from AbstractCommandController.
46: * ThrowawayController is specifically intended for controllers that are not aware
47: * of the Servlet API at all. Accordingly, if you need to handle session form objects
48: * or even wizard forms, consider the corresponding Controller subclasses.
49: *
50: * @author Juergen Hoeller
51: * @since 08.12.2003
52: * @see org.springframework.web.servlet.mvc.Controller
53: * @see org.springframework.web.servlet.mvc.AbstractCommandController
54: */
55: public interface ThrowawayController {
56:
57: /**
58: * Execute this controller according to its bean properties.
59: * Gets invoked after a new instance of the controller has been populated with request
60: * parameters. Is supposed to return a ModelAndView in any case, as it is not able to
61: * generate a response itself.
62: * @return a ModelAndView to render
63: * @throws Exception in case of errors
64: */
65: ModelAndView execute() throws Exception;
66:
67: }
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