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.portlet.handler;
18
19 import java.util.ArrayList;
20 import java.util.Arrays;
21 import java.util.List;
22 import javax.portlet.PortletRequest;
23
24 import org.springframework.beans.BeansException;
25 import org.springframework.context.support.ApplicationObjectSupport;
26 import org.springframework.core.Ordered;
27 import org.springframework.web.context.request.WebRequestInterceptor;
28 import org.springframework.web.portlet.HandlerExecutionChain;
29 import org.springframework.web.portlet.HandlerInterceptor;
30 import org.springframework.web.portlet.HandlerMapping;
31
32 /**
33 * Abstract base class for {@link org.springframework.web.portlet.HandlerMapping}
34 * implementations. Supports ordering, a default handler, and handler interceptors.
35 *
36 * @author Juergen Hoeller
37 * @author John A. Lewis
38 * @since 2.0
39 * @see #getHandlerInternal
40 * @see #setDefaultHandler
41 * @see #setInterceptors
42 * @see org.springframework.web.portlet.HandlerInterceptor
43 */
44 public abstract class AbstractHandlerMapping extends ApplicationObjectSupport implements HandlerMapping, Ordered {
45
46 private int order = Integer.MAX_VALUE; // default: same as non-Ordered
47
48 private Object defaultHandler;
49
50 private final List<Object> interceptors = new ArrayList<Object>();
51
52 private boolean applyWebRequestInterceptorsToRenderPhaseOnly = true;
53
54 private HandlerInterceptor[] adaptedInterceptors;
55
56
57 /**
58 * Specify the order value for this HandlerMapping bean.
59 * <p>Default value is {@code Integer.MAX_VALUE}, meaning that it's non-ordered.
60 * @see org.springframework.core.Ordered#getOrder()
61 */
62 public final void setOrder(int order) {
63 this.order = order;
64 }
65
66 @Override
67 public final int getOrder() {
68 return this.order;
69 }
70
71 /**
72 * Set the default handler for this handler mapping.
73 * This handler will be returned if no specific mapping was found.
74 * <p>Default is {@code null}, indicating no default handler.
75 */
76 public void setDefaultHandler(Object defaultHandler) {
77 this.defaultHandler = defaultHandler;
78 }
79
80 /**
81 * Return the default handler for this handler mapping,
82 * or {@code null} if none.
83 */
84 public Object getDefaultHandler() {
85 return this.defaultHandler;
86 }
87
88 /**
89 * Set the interceptors to apply for all handlers mapped by this handler mapping.
90 * <p>Supported interceptor types are HandlerInterceptor and WebRequestInterceptor.
91 * Each given WebRequestInterceptor will be wrapped in a WebRequestHandlerInterceptorAdapter.
92 * @param interceptors array of handler interceptors, or {@code null} if none
93 * @see #adaptInterceptor
94 * @see org.springframework.web.portlet.HandlerInterceptor
95 * @see org.springframework.web.context.request.WebRequestInterceptor
96 */
97 public void setInterceptors(Object[] interceptors) {
98 this.interceptors.addAll(Arrays.asList(interceptors));
99 }
100
101 /**
102 * Specify whether to apply WebRequestInterceptors to the Portlet render phase
103 * only ("true", or whether to apply them to the Portlet action phase as well
104 * ("false").
105 * <p>Default is "true", since WebRequestInterceptors are usually built for
106 * MVC-style handler execution plus rendering process (which is, for example,
107 * the primary target scenario for "Open Session in View" interceptors,
108 * offering lazy loading of persistent objects during view rendering).
109 * Set this to "false" to have WebRequestInterceptors apply to the action
110 * phase as well (for example, in case of an "Open Session in View" interceptor,
111 * to allow for lazy loading outside of a transaction during the action phase).
112 * @see #setInterceptors
113 * @see org.springframework.web.context.request.WebRequestInterceptor
114 * @see WebRequestHandlerInterceptorAdapter#WebRequestHandlerInterceptorAdapter(WebRequestInterceptor, boolean)
115 * @see org.springframework.orm.jpa.support.OpenEntityManagerInViewInterceptor
116 */
117 public void setApplyWebRequestInterceptorsToRenderPhaseOnly(boolean applyWebRequestInterceptorsToRenderPhaseOnly) {
118 this.applyWebRequestInterceptorsToRenderPhaseOnly = applyWebRequestInterceptorsToRenderPhaseOnly;
119 }
120
121
122 /**
123 * Initializes the interceptors.
124 * @see #extendInterceptors(java.util.List)
125 * @see #initInterceptors()
126 */
127 @Override
128 protected void initApplicationContext() throws BeansException {
129 extendInterceptors(this.interceptors);
130 initInterceptors();
131 }
132
133 /**
134 * Extension hook that subclasses can override to register additional interceptors,
135 * given the configured interceptors (see {@link #setInterceptors}).
136 * <p>Will be invoked before {@link #initInterceptors()} adapts the specified
137 * interceptors into {@link HandlerInterceptor} instances.
138 * <p>The default implementation is empty.
139 * @param interceptors the configured interceptor List (never {@code null}),
140 * allowing to add further interceptors before as well as after the existing
141 * interceptors
142 */
143 protected void extendInterceptors(List<?> interceptors) {
144 }
145
146 /**
147 * Initialize the specified interceptors, adapting them where necessary.
148 * @see #setInterceptors
149 * @see #adaptInterceptor
150 */
151 protected void initInterceptors() {
152 if (!this.interceptors.isEmpty()) {
153 this.adaptedInterceptors = new HandlerInterceptor[this.interceptors.size()];
154 for (int i = 0; i < this.interceptors.size(); i++) {
155 Object interceptor = this.interceptors.get(i);
156 if (interceptor == null) {
157 throw new IllegalArgumentException("Entry number " + i + " in interceptors array is null");
158 }
159 this.adaptedInterceptors[i] = adaptInterceptor(interceptor);
160 }
161 }
162 }
163
164 /**
165 * Adapt the given interceptor object to the HandlerInterceptor interface.
166 * <p>Supported interceptor types are HandlerInterceptor and WebRequestInterceptor.
167 * Each given WebRequestInterceptor will be wrapped in a WebRequestHandlerInterceptorAdapter.
168 * Can be overridden in subclasses.
169 * @param interceptor the specified interceptor object
170 * @return the interceptor wrapped as HandlerInterceptor
171 * @see #setApplyWebRequestInterceptorsToRenderPhaseOnly
172 * @see org.springframework.web.portlet.HandlerInterceptor
173 * @see org.springframework.web.context.request.WebRequestInterceptor
174 * @see WebRequestHandlerInterceptorAdapter
175 */
176 protected HandlerInterceptor adaptInterceptor(Object interceptor) {
177 if (interceptor instanceof HandlerInterceptor) {
178 return (HandlerInterceptor) interceptor;
179 }
180 else if (interceptor instanceof WebRequestInterceptor) {
181 return new WebRequestHandlerInterceptorAdapter(
182 (WebRequestInterceptor) interceptor, this.applyWebRequestInterceptorsToRenderPhaseOnly);
183 }
184 else {
185 throw new IllegalArgumentException("Interceptor type not supported: " + interceptor.getClass().getName());
186 }
187 }
188
189 /**
190 * Return the adapted interceptors as HandlerInterceptor array.
191 * @return the array of HandlerInterceptors, or {@code null} if none
192 */
193 protected final HandlerInterceptor[] getAdaptedInterceptors() {
194 return this.adaptedInterceptors;
195 }
196
197
198 /**
199 * Look up a handler for the given request, falling back to the default
200 * handler if no specific one is found.
201 * @param request current portlet request
202 * @return the corresponding handler instance, or the default handler
203 * @see #getHandlerInternal
204 */
205 @Override
206 public final HandlerExecutionChain getHandler(PortletRequest request) throws Exception {
207 Object handler = getHandlerInternal(request);
208 if (handler == null) {
209 handler = getDefaultHandler();
210 }
211 if (handler == null) {
212 return null;
213 }
214 // Bean name or resolved handler?
215 if (handler instanceof String) {
216 String handlerName = (String) handler;
217 handler = getApplicationContext().getBean(handlerName);
218 }
219 return getHandlerExecutionChain(handler, request);
220 }
221
222 /**
223 * Look up a handler for the given request, returning {@code null} if no
224 * specific one is found. This method is called by {@link #getHandler};
225 * a {@code null} return value will lead to the default handler, if one is set.
226 * <p>Note: This method may also return a pre-built {@link HandlerExecutionChain},
227 * combining a handler object with dynamically determined interceptors.
228 * Statically specified interceptors will get merged into such an existing chain.
229 * @param request current portlet request
230 * @return the corresponding handler instance, or {@code null} if none found
231 * @throws Exception if there is an internal error
232 * @see #getHandler
233 */
234 protected abstract Object getHandlerInternal(PortletRequest request) throws Exception;
235
236 /**
237 * Build a HandlerExecutionChain for the given handler, including applicable interceptors.
238 * <p>The default implementation simply builds a standard HandlerExecutionChain with
239 * the given handler and this handler mapping's common interceptors. Subclasses may
240 * override this in order to extend/rearrange the list of interceptors.
241 * <p><b>NOTE:</b> The passed-in handler object may be a raw handler or a pre-built
242 * HandlerExecutionChain. This method should handle those two cases explicitly,
243 * either building a new HandlerExecutionChain or extending the existing chain.
244 * <p>For simply adding an interceptor, consider calling {@code super.getHandlerExecutionChain}
245 * and invoking {@link HandlerExecutionChain#addInterceptor} on the returned chain object.
246 * @param handler the resolved handler instance (never {@code null})
247 * @param request current portlet request
248 * @return the HandlerExecutionChain (never {@code null})
249 * @see #getAdaptedInterceptors()
250 */
251 protected HandlerExecutionChain getHandlerExecutionChain(Object handler, PortletRequest request) {
252 if (handler instanceof HandlerExecutionChain) {
253 HandlerExecutionChain chain = (HandlerExecutionChain) handler;
254 chain.addInterceptors(getAdaptedInterceptors());
255 return chain;
256 }
257 else {
258 return new HandlerExecutionChain(handler, getAdaptedInterceptors());
259 }
260 }
261
262 }