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Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
IRequestCycle.java | - | - | - | - |
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1 | // Copyright 2004, 2005 The Apache Software Foundation | |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); | |
4 | // you may not use this file except in compliance with the License. | |
5 | // You may obtain a copy of the License at | |
6 | // | |
7 | // http://www.apache.org/licenses/LICENSE-2.0 | |
8 | // | |
9 | // Unless required by applicable law or agreed to in writing, software | |
10 | // distributed under the License is distributed on an "AS IS" BASIS, | |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
12 | // See the License for the specific language governing permissions and | |
13 | // limitations under the License. | |
14 | ||
15 | package org.apache.tapestry; | |
16 | ||
17 | import org.apache.hivemind.ApplicationRuntimeException; | |
18 | import org.apache.tapestry.engine.IEngineService; | |
19 | import org.apache.tapestry.engine.IMonitor; | |
20 | import org.apache.tapestry.request.RequestContext; | |
21 | import org.apache.tapestry.services.Infrastructure; | |
22 | ||
23 | /** | |
24 | * Controller object that manages a single request cycle. A request cycle is one 'hit' on the web | |
25 | * server. In the case of a Tapestry application, this will involve: | |
26 | * <ul> | |
27 | * <li>Responding to the URL by finding an {@link IEngineService}object | |
28 | * <li>Determining the result page | |
29 | * <li>Renderring the result page | |
30 | * <li>Releasing any resources | |
31 | * </ul> | |
32 | * <p> | |
33 | * Mixed in with this is: | |
34 | * <ul> | |
35 | * <li>Exception handling | |
36 | * <li>Loading of pages and templates from resources | |
37 | * <li>Tracking changes to page properties, and restoring pages to prior states | |
38 | * <li>Pooling of page objects | |
39 | * </ul> | |
40 | * <p> | |
41 | * A request cycle is broken up into two phases. The <em>rewind</em> phase is optional, as it tied | |
42 | * to {@link org.apache.tapestry.link.ActionLink}or {@link org.apache.tapestry.form.Form} | |
43 | * components. In the rewind phase, a previous page render is redone (discarding output) until a | |
44 | * specific component of the page is reached. This rewinding ensures that the page is restored to | |
45 | * the exact state it had when the URL for the request cycle was generated, taking into account the | |
46 | * dynamic nature of the page ({@link org.apache.tapestry.components.Foreach}, | |
47 | * {@link org.apache.tapestry.components.Conditional}, etc.). Once this component is reached, it | |
48 | * can notify its {@link IActionListener}. The listener has the ability to update the state of any | |
49 | * pages and select a new result page. | |
50 | * <p> | |
51 | * Following the rewind phase is the <em>render</em> phase. During the render phase, a page is | |
52 | * actually rendered and output sent to the client web browser. | |
53 | * | |
54 | * @author Howard Lewis Ship | |
55 | */ | |
56 | ||
57 | public interface IRequestCycle | |
58 | { | |
59 | /** | |
60 | * Invoked after the request cycle is no longer needed, to release any resources it may have. | |
61 | * This includes releasing any loaded pages back to the page source. | |
62 | */ | |
63 | ||
64 | public void cleanup(); | |
65 | ||
66 | /** | |
67 | * Passes the String through | |
68 | * {@link javax.servlet.http.HttpServletResponse#encodeURL(java.lang.String)}, which ensures | |
69 | * that the session id is encoded in the URL (if necessary). | |
70 | */ | |
71 | ||
72 | public String encodeURL(String URL); | |
73 | ||
74 | /** | |
75 | * Returns the engine which is processing this request cycle. | |
76 | */ | |
77 | ||
78 | public IEngine getEngine(); | |
79 | ||
80 | /** | |
81 | * Retrieves a previously stored attribute, returning null if not found. Attributes allow | |
82 | * components to locate each other; primarily they allow a wrapped component to locate a | |
83 | * component which wraps it. Attributes are cleared at the end of the render (or rewind). | |
84 | */ | |
85 | ||
86 | public Object getAttribute(String name); | |
87 | ||
88 | public IMonitor getMonitor(); | |
89 | ||
90 | /** | |
91 | * Returns the next action id. ActionLink ids are used to identify different actions on a page | |
92 | * (URLs that are related to dynamic page state). | |
93 | */ | |
94 | ||
95 | public String getNextActionId(); | |
96 | ||
97 | /** | |
98 | * Identifies the active page, the page which will ultimately render the response. | |
99 | */ | |
100 | ||
101 | public IPage getPage(); | |
102 | ||
103 | /** | |
104 | * Returns the page with the given name. If the page has been previously loaded in the current | |
105 | * request cycle, that page is returned. Otherwise, the engine's page loader is used to load the | |
106 | * page. | |
107 | * | |
108 | * @throws PageNotFoundException | |
109 | * if the page does not exist. | |
110 | * @see org.apache.tapestry.engine.IPageSource#getPage(IRequestCycle, String, IMonitor) | |
111 | */ | |
112 | ||
113 | public IPage getPage(String name); | |
114 | ||
115 | /** | |
116 | * Returns true if the context is being used to rewind a prior state of the page. This is only | |
117 | * true when there is a target action id. | |
118 | */ | |
119 | ||
120 | public boolean isRewinding(); | |
121 | ||
122 | /** | |
123 | * Checks to see if the current action id matches the target action id. Returns true only if | |
124 | * they match. Returns false if there is no target action id (that is, during page rendering). | |
125 | * <p> | |
126 | * If theres a match on action id, then the component is compared against the target component. | |
127 | * If there's a mismatch then a {@link StaleLinkException}is thrown. | |
128 | */ | |
129 | ||
130 | public boolean isRewound(IComponent component) throws StaleLinkException; | |
131 | ||
132 | /** | |
133 | * Removes a previously stored attribute, if one with the given name exists. | |
134 | */ | |
135 | ||
136 | public void removeAttribute(String name); | |
137 | ||
138 | /** | |
139 | * Renders the given page. Applications should always use this method to render the page, rather | |
140 | * than directly invoking {@link IPage#render(IMarkupWriter, IRequestCycle)}since the request | |
141 | * cycle must perform some setup before rendering. | |
142 | */ | |
143 | ||
144 | public void renderPage(IMarkupWriter writer); | |
145 | ||
146 | /** | |
147 | * Rewinds a page and executes some form of action when the component with the specified action | |
148 | * id is reached. | |
149 | * | |
150 | * @see IAction | |
151 | * @see org.apache.tapestry.link.ActionLink | |
152 | */ | |
153 | ||
154 | public void rewindPage(String targetActionId, IComponent targetComponent); | |
155 | ||
156 | /** | |
157 | * Allows a temporary object to be stored in the request cycle, which allows otherwise unrelated | |
158 | * objects to communicate. This is similar to <code>HttpServletRequest.setAttribute()</code>, | |
159 | * except that values can be changed and removed as well. | |
160 | * <p> | |
161 | * This is used by components to locate each other. A component, such as | |
162 | * {@link org.apache.tapestry.html.Body}, will write itself under a well-known name into the | |
163 | * request cycle, and components it wraps can locate it by that name. | |
164 | * <p> | |
165 | * Attributes are cleared at the end of each render or rewind phase. | |
166 | */ | |
167 | ||
168 | public void setAttribute(String name, Object value); | |
169 | ||
170 | /** | |
171 | * Invoked just before rendering the response page to get all | |
172 | * {@link org.apache.tapestry.engine.IPageRecorder page recorders}touched in this request cycle | |
173 | * to commit their changes (save them to persistant storage). | |
174 | * | |
175 | * @see org.apache.tapestry.engine.IPageRecorder#commit() | |
176 | */ | |
177 | ||
178 | public void commitPageChanges(); | |
179 | ||
180 | /** | |
181 | * Returns the service which initiated this request cycle. | |
182 | * | |
183 | * @since 1.0.1 | |
184 | */ | |
185 | ||
186 | public IEngineService getService(); | |
187 | ||
188 | /** | |
189 | * Used by {@link IForm forms}to perform a <em>partial</em> rewind so as to respond to the | |
190 | * form submission (using the direct service). | |
191 | * <p> | |
192 | * Note: the targetActionId parameter was removed in release 4.0. | |
193 | * | |
194 | * @since 1.0.2 | |
195 | */ | |
196 | ||
197 | public void rewindForm(IForm form); | |
198 | ||
199 | /** | |
200 | * Much like {@link #forgetPage(String)}, but the page stays active and can even record | |
201 | * changes, until the end of the request cycle, at which point it is discarded (and any recorded | |
202 | * changes are lost). This is used in certain rare cases where a page has persistent state but | |
203 | * is being renderred "for the last time". | |
204 | * | |
205 | * @since 2.0.2 | |
206 | * @deprecated To be removed in 4.1. Use {@link #forgetPage(String)}. | |
207 | */ | |
208 | ||
209 | public void discardPage(String name); | |
210 | ||
211 | /** | |
212 | * Invoked by a {@link IEngineService service} to store an array of application-specific | |
213 | * parameters. These can later be retrieved (typically, by an application-specific listener | |
214 | * method) by invoking {@link #getServiceParameters()}. | |
215 | * <p> | |
216 | * Through release 2.1, parameters was of type String[]. This is an incompatible change in 2.2. | |
217 | * | |
218 | * @see org.apache.tapestry.engine.DirectService | |
219 | * @since 2.0.3 | |
220 | * @deprecated To be removed in 4.1. Use {@link #setListenerParameters(Object[])}instead. | |
221 | */ | |
222 | ||
223 | public void setServiceParameters(Object[] parameters); | |
224 | ||
225 | /** | |
226 | * Invoked by a {@link IEngineService service} to store an array of application-specific | |
227 | * parameters. These can later be retrieved (typically, by an application-specific listener | |
228 | * method) by invoking {@link #getListenerParameters()}. | |
229 | * | |
230 | * @see org.apache.tapestry.engine.DirectService | |
231 | * @since 4.0 | |
232 | */ | |
233 | public void setListenerParameters(Object[] parameters); | |
234 | ||
235 | /** | |
236 | * Returns parameters previously stored by {@link #setServiceParameters(Object[])}. | |
237 | * <p> | |
238 | * Through release 2.1, the return type was String[]. This is an incompatible change in 2.2. | |
239 | * | |
240 | * @since 2.0.3 | |
241 | * @deprecated To be removed in 4.1. Use {@link #getListenerParameters()}instead. | |
242 | */ | |
243 | ||
244 | public Object[] getServiceParameters(); | |
245 | ||
246 | /** | |
247 | * Returns parameters previously stored by {@link #setListenerParameters(Object[])}. | |
248 | * | |
249 | * @since 4.0 | |
250 | */ | |
251 | ||
252 | public Object[] getListenerParameters(); | |
253 | ||
254 | /** | |
255 | * A convienience for invoking {@link #activate(IPage)}. Invokes {@link #getPage(String)}to | |
256 | * get an instance of the named page. | |
257 | * | |
258 | * @since 3.0 | |
259 | */ | |
260 | ||
261 | public void activate(String name); | |
262 | ||
263 | /** | |
264 | * Sets the active page for the request. The active page is the page which will ultimately | |
265 | * render the response. The activate page is typically set by the {@link IEngineService service}. | |
266 | * Frequently, the active page is changed (from a listener method) to choose an alternate page | |
267 | * to render the response). | |
268 | * <p> | |
269 | * {@link IPage#validate(IRequestCycle)}is invoked on the page to be activated. | |
270 | * {@link PageRedirectException}is caught and the page specified in the exception will be the | |
271 | * active page instead (that is, a page may "pass the baton" to another page using the | |
272 | * exception). The new page is also validated. This continues until a page does not throw | |
273 | * {@link PageRedirectException}. | |
274 | * <p> | |
275 | * Validation loops can occur, where page A redirects to page B and then page B redirects back | |
276 | * to page A (possibly with intermediate steps). This is detected and results in an | |
277 | * {@link ApplicationRuntimeException}. | |
278 | * | |
279 | * @since 3.0 | |
280 | */ | |
281 | public void activate(IPage page); | |
282 | ||
283 | /** | |
284 | * Returns a query parameter value, or null if not provided in the request. If multiple values | |
285 | * are provided, returns the first value. | |
286 | * | |
287 | * @since 4.0 | |
288 | */ | |
289 | public String getParameter(String name); | |
290 | ||
291 | /** | |
292 | * Returns all query parameter values for the given name. Returns null if no values were | |
293 | * provided. | |
294 | * | |
295 | * @since 4.0 | |
296 | */ | |
297 | public String[] getParameters(String name); | |
298 | ||
299 | /** | |
300 | * Converts a partial URL into an absolute URL. Prefixes the provided URL with servlet context | |
301 | * path (if any), then expands it to a full URL by prepending with the scheme, server and port | |
302 | * (determined from the current {@link org.apache.tapestry.web.WebRequest request}. | |
303 | * | |
304 | * @since 4.0 | |
305 | */ | |
306 | ||
307 | public String getAbsoluteURL(String partialURL); | |
308 | ||
309 | /** | |
310 | * Forgets any stored changes to the specified page. If the page has already been loaded (and | |
311 | * rolled back) then the loaded page instance is not affected; if the page is only loaded | |
312 | * subsequently, the page instance will not see any persisted property changes. | |
313 | * | |
314 | * @since 4.0 | |
315 | */ | |
316 | ||
317 | public void forgetPage(String name); | |
318 | ||
319 | /** | |
320 | * Returns the central {@link org.apache.tapestry.services.Infrastructure} object used to | |
321 | * manage the processing of the request. | |
322 | * | |
323 | * @since 4.0 | |
324 | */ | |
325 | ||
326 | public Infrastructure getInfrastructure(); | |
327 | ||
328 | /** | |
329 | * Returns the {@link RequestContext}. This is provided to ease the upgrade from Tapestry 3.0. | |
330 | * | |
331 | * @deprecated To be removed in 4.1. | |
332 | */ | |
333 | ||
334 | public RequestContext getRequestContext(); | |
335 | ||
336 | /** | |
337 | * Returns the provided string, possibly modified (with an appended suffix) to make it unique. | |
338 | * | |
339 | * @param baseId | |
340 | * the base id from which to generate the unique string. | |
341 | * @return baseId, or baseId with a suffix appended (if the method has been previously invoked | |
342 | * with the same baseId). | |
343 | */ | |
344 | ||
345 | public String getUniqueId(String baseId); | |
346 | } |
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