1 /*
2 * Copyright 2002-2014 the original author or authors.
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
17 package org.springframework.web.servlet.mvc.method;
18
19 import javax.servlet.http.HttpServletRequest;
20 import javax.servlet.http.HttpServletResponse;
21
22 import org.springframework.core.Ordered;
23 import org.springframework.web.method.HandlerMethod;
24 import org.springframework.web.servlet.HandlerAdapter;
25 import org.springframework.web.servlet.ModelAndView;
26 import org.springframework.web.servlet.support.WebContentGenerator;
27
28 /**
29 * Abstract base class for {@link HandlerAdapter} implementations that support
30 * handlers of type {@link HandlerMethod}.
31 *
32 * @author Arjen Poutsma
33 * @since 3.1
34 */
35 public abstract class AbstractHandlerMethodAdapter extends WebContentGenerator implements HandlerAdapter, Ordered {
36
37 private int order = Ordered.LOWEST_PRECEDENCE;
38
39
40 public AbstractHandlerMethodAdapter() {
41 // no restriction of HTTP methods by default
42 super(false);
43 }
44
45
46 /**
47 * Specify the order value for this HandlerAdapter bean.
48 * <p>Default value is {@code Integer.MAX_VALUE}, meaning that it's non-ordered.
49 * @see org.springframework.core.Ordered#getOrder()
50 */
51 public void setOrder(int order) {
52 this.order = order;
53 }
54
55 @Override
56 public int getOrder() {
57 return this.order;
58 }
59
60
61 /**
62 * This implementation expects the handler to be an {@link HandlerMethod}.
63 * @param handler the handler instance to check
64 * @return whether or not this adapter can adapt the given handler
65 */
66 @Override
67 public final boolean supports(Object handler) {
68 return (handler instanceof HandlerMethod && supportsInternal((HandlerMethod) handler));
69 }
70
71 /**
72 * Given a handler method, return whether or not this adapter can support it.
73 * @param handlerMethod the handler method to check
74 * @return whether or not this adapter can adapt the given method
75 */
76 protected abstract boolean supportsInternal(HandlerMethod handlerMethod);
77
78 /**
79 * This implementation expects the handler to be an {@link HandlerMethod}.
80 */
81 @Override
82 public final ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
83 throws Exception {
84
85 return handleInternal(request, response, (HandlerMethod) handler);
86 }
87
88 /**
89 * Use the given handler method to handle the request.
90 * @param request current HTTP request
91 * @param response current HTTP response
92 * @param handlerMethod handler method to use. This object must have previously been passed to the
93 * {@link #supportsInternal(HandlerMethod)} this interface, which must have returned {@code true}.
94 * @return ModelAndView object with the name of the view and the required model data,
95 * or {@code null} if the request has been handled directly
96 * @throws Exception in case of errors
97 */
98 protected abstract ModelAndView handleInternal(HttpServletRequest request,
99 HttpServletResponse response, HandlerMethod handlerMethod) throws Exception;
100
101 /**
102 * This implementation expects the handler to be an {@link HandlerMethod}.
103 */
104 @Override
105 public final long getLastModified(HttpServletRequest request, Object handler) {
106 return getLastModifiedInternal(request, (HandlerMethod) handler);
107 }
108
109 /**
110 * Same contract as for {@link javax.servlet.http.HttpServlet#getLastModified(HttpServletRequest)}.
111 * @param request current HTTP request
112 * @param handlerMethod handler method to use
113 * @return the lastModified value for the given handler
114 */
115 protected abstract long getLastModifiedInternal(HttpServletRequest request, HandlerMethod handlerMethod);
116
117 }