Clover coverage report - Code Coverage for tapestry release 4.0-beta-8
Coverage timestamp: Sat Sep 24 2005 11:50:34 EDT
file stats: LOC: 355   Methods: 0
NCLOC: 39   Classes: 1
 
 Source file Conditionals Statements Methods TOTAL
IRequestCycle.java - - - -
coverage
 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.tapestry.engine.IEngineService;
 18    import org.apache.tapestry.engine.IMonitor;
 19    import org.apache.tapestry.request.RequestContext;
 20    import org.apache.tapestry.services.Infrastructure;
 21   
 22    /**
 23    * Controller object that manages a single request cycle. A request cycle is one 'hit' on the web
 24    * server. In the case of a Tapestry application, this will involve:
 25    * <ul>
 26    * <li>Responding to the URL by finding an {@link IEngineService}object
 27    * <li>Determining the result page
 28    * <li>Renderring the result page
 29    * <li>Releasing any resources
 30    * </ul>
 31    * <p>
 32    * Mixed in with this is:
 33    * <ul>
 34    * <li>Exception handling
 35    * <li>Loading of pages and templates from resources
 36    * <li>Tracking changes to page properties, and restoring pages to prior states
 37    * <li>Pooling of page objects
 38    * </ul>
 39    * <p>
 40    * A request cycle is broken up into two phases. The <em>rewind</em> phase is optional, as it tied
 41    * to {@link org.apache.tapestry.link.ActionLink}or {@link org.apache.tapestry.form.Form}
 42    * components. In the rewind phase, a previous page render is redone (discarding output) until a
 43    * specific component of the page is reached. This rewinding ensures that the page is restored to
 44    * the exact state it had when the URL for the request cycle was generated, taking into account the
 45    * dynamic nature of the page ({@link org.apache.tapestry.components.Foreach},
 46    * {@link org.apache.tapestry.components.Conditional}, etc.). Once this component is reached, it
 47    * can notify its {@link IActionListener}. The listener has the ability to update the state of any
 48    * pages and select a new result page.
 49    * <p>
 50    * Following the rewind phase is the <em>render</em> phase. During the render phase, a page is
 51    * actually rendered and output sent to the client web browser.
 52    *
 53    * @author Howard Lewis Ship
 54    */
 55   
 56    public interface IRequestCycle
 57    {
 58    /**
 59    * Invoked after the request cycle is no longer needed, to release any resources it may have.
 60    * This includes releasing any loaded pages back to the page source.
 61    */
 62   
 63    public void cleanup();
 64   
 65    /**
 66    * Passes the String through
 67    * {@link javax.servlet.http.HttpServletResponse#encodeURL(java.lang.String)}, which ensures
 68    * that the session id is encoded in the URL (if necessary).
 69    */
 70   
 71    public String encodeURL(String URL);
 72   
 73    /**
 74    * Returns the engine which is processing this request cycle.
 75    */
 76   
 77    public IEngine getEngine();
 78   
 79    /**
 80    * Retrieves a previously stored attribute, returning null if not found. Attributes allow
 81    * components to locate each other; primarily they allow a wrapped component to locate a
 82    * component which wraps it. Attributes are cleared at the end of the render (or rewind).
 83    */
 84   
 85    public Object getAttribute(String name);
 86   
 87    public IMonitor getMonitor();
 88   
 89    /**
 90    * Returns the next action id. ActionLink ids are used to identify different actions on a page
 91    * (URLs that are related to dynamic page state).
 92    */
 93   
 94    public String getNextActionId();
 95   
 96    /**
 97    * Identifies the active page, the page which will ultimately render the response.
 98    */
 99   
 100    public IPage getPage();
 101   
 102    /**
 103    * Returns the page with the given name. If the page has been previously loaded in the current
 104    * request cycle, that page is returned. Otherwise, the engine's page loader is used to load the
 105    * page.
 106    *
 107    * @throws PageNotFoundException
 108    * if the page does not exist.
 109    * @see org.apache.tapestry.engine.IPageSource#getPage(IRequestCycle, String, IMonitor)
 110    */
 111   
 112    public IPage getPage(String name);
 113   
 114    /**
 115    * Returns true if the context is being used to rewind a prior state of the page. This is only
 116    * true when there is a target action id.
 117    */
 118   
 119    public boolean isRewinding();
 120   
 121    /**
 122    * Checks to see if the current action id matches the target action id. Returns true only if
 123    * they match. Returns false if there is no target action id (that is, during page rendering).
 124    * <p>
 125    * If theres a match on action id, then the component is compared against the target component.
 126    * If there's a mismatch then a {@link StaleLinkException}is thrown.
 127    */
 128   
 129    public boolean isRewound(IComponent component) throws StaleLinkException;
 130   
 131    /**
 132    * Removes a previously stored attribute, if one with the given name exists.
 133    */
 134   
 135    public void removeAttribute(String name);
 136   
 137    /**
 138    * Renders the given page. Applications should always use this method to render the page, rather
 139    * than directly invoking {@link IPage#render(IMarkupWriter, IRequestCycle)}since the request
 140    * cycle must perform some setup before rendering.
 141    */
 142   
 143    public void renderPage(IMarkupWriter writer);
 144   
 145    /**
 146    * Rewinds a page and executes some form of action when the component with the specified action
 147    * id is reached.
 148    *
 149    * @see IAction
 150    * @see org.apache.tapestry.link.ActionLink
 151    */
 152   
 153    public void rewindPage(String targetActionId, IComponent targetComponent);
 154   
 155    /**
 156    * Allows a temporary object to be stored in the request cycle, which allows otherwise unrelated
 157    * objects to communicate. This is similar to <code>HttpServletRequest.setAttribute()</code>,
 158    * except that values can be changed and removed as well.
 159    * <p>
 160    * This is used by components to locate each other. A component, such as
 161    * {@link org.apache.tapestry.html.Body}, will write itself under a well-known name into the
 162    * request cycle, and components it wraps can locate it by that name.
 163    * <p>
 164    * Attributes are cleared at the end of each render or rewind phase.
 165    */
 166   
 167    public void setAttribute(String name, Object value);
 168   
 169    /**
 170    * Invoked just before rendering the response page to get all
 171    * {@link org.apache.tapestry.engine.IPageRecorder page recorders}touched in this request cycle
 172    * to commit their changes (save them to persistant storage).
 173    *
 174    * @see org.apache.tapestry.engine.IPageRecorder#commit()
 175    */
 176   
 177    public void commitPageChanges();
 178   
 179    /**
 180    * Returns the service which initiated this request cycle.
 181    *
 182    * @since 1.0.1
 183    */
 184   
 185    public IEngineService getService();
 186   
 187    /**
 188    * Used by {@link IForm forms}to perform a <em>partial</em> rewind so as to respond to the
 189    * form submission (using the direct service).
 190    * <p>
 191    * Note: the targetActionId parameter was removed in release 4.0.
 192    *
 193    * @since 1.0.2
 194    */
 195   
 196    public void rewindForm(IForm form);
 197   
 198    /**
 199    * Much like {@link #forgetPage(String)}, but the page stays active and can even record
 200    * changes, until the end of the request cycle, at which point it is discarded (and any recorded
 201    * changes are lost). This is used in certain rare cases where a page has persistent state but
 202    * is being renderred "for the last time".
 203    *
 204    * @since 2.0.2
 205    * @deprecated To be removed in 4.1. Use {@link #forgetPage(String)}.
 206    */
 207   
 208    public void discardPage(String name);
 209   
 210    /**
 211    * Invoked by a {@link IEngineService service}&nbsp;to store an array of application-specific
 212    * parameters. These can later be retrieved (typically, by an application-specific listener
 213    * method) by invoking {@link #getServiceParameters()}.
 214    * <p>
 215    * Through release 2.1, parameters was of type String[]. This is an incompatible change in 2.2.
 216    *
 217    * @see org.apache.tapestry.engine.DirectService
 218    * @since 2.0.3
 219    * @deprecated To be removed in 4.1. Use {@link #setListenerParameters(Object[])}instead.
 220    */
 221   
 222    public void setServiceParameters(Object[] parameters);
 223   
 224    /**
 225    * Invoked by a {@link IEngineService service}&nbsp;to store an array of application-specific
 226    * parameters. These can later be retrieved (typically, by an application-specific listener
 227    * method) by invoking {@link #getListenerParameters()}.
 228    *
 229    * @see org.apache.tapestry.engine.DirectService
 230    * @since 4.0
 231    */
 232    public void setListenerParameters(Object[] parameters);
 233   
 234    /**
 235    * Returns parameters previously stored by {@link #setServiceParameters(Object[])}.
 236    * <p>
 237    * Through release 2.1, the return type was String[]. This is an incompatible change in 2.2.
 238    *
 239    * @since 2.0.3
 240    * @deprecated To be removed in 4.1. Use {@link #getListenerParameters()}instead.
 241    */
 242   
 243    public Object[] getServiceParameters();
 244   
 245    /**
 246    * Returns parameters previously stored by {@link #setListenerParameters(Object[])}.
 247    *
 248    * @since 4.0
 249    */
 250   
 251    public Object[] getListenerParameters();
 252   
 253    /**
 254    * A convienience for invoking {@link #activate(IPage)}. Invokes {@link #getPage(String)}to
 255    * get an instance of the named page.
 256    *
 257    * @since 3.0
 258    */
 259   
 260    public void activate(String name);
 261   
 262    /**
 263    * Sets the active page for the request. The active page is the page which will ultimately
 264    * render the response. The activate page is typically set by the {@link IEngineService service}.
 265    * Frequently, the active page is changed (from a listener method) to choose an alternate page
 266    * to render the response).
 267    * <p>
 268    * {@link IPage#validate(IRequestCycle)}is invoked on the page to be activated.
 269    * {@link PageRedirectException}is caught and the page specified in the exception will be the
 270    * active page instead (that is, a page may "pass the baton" to another page using the
 271    * exception). The new page is also validated. This continues until a page does not throw
 272    * {@link PageRedirectException}.
 273    * <p>
 274    * Validation loops can occur, where page A redirects to page B and then page B redirects back
 275    * to page A (possibly with intermediate steps). This is detected and results in an
 276    * {@link ApplicationRuntimeException}.
 277    *
 278    * @since 3.0
 279    */
 280    public void activate(IPage page);
 281   
 282    /**
 283    * Returns a query parameter value, or null if not provided in the request. If multiple values
 284    * are provided, returns the first value.
 285    *
 286    * @since 4.0
 287    */
 288    public String getParameter(String name);
 289   
 290    /**
 291    * Returns all query parameter values for the given name. Returns null if no values were
 292    * provided.
 293    *
 294    * @since 4.0
 295    */
 296    public String[] getParameters(String name);
 297   
 298    /**
 299    * Converts a partial URL into an absolute URL. Prefixes the provided URL with servlet context
 300    * path (if any), then expands it to a full URL by prepending with the scheme, server and port
 301    * (determined from the current {@link org.apache.tapestry.web.WebRequest request}.
 302    *
 303    * @since 4.0
 304    */
 305   
 306    public String getAbsoluteURL(String partialURL);
 307   
 308    /**
 309    * Forgets any stored changes to the specified page. If the page has already been loaded (and
 310    * rolled back) then the loaded page instance is not affected; if the page is only loaded
 311    * subsequently, the page instance will not see any persisted property changes.
 312    *
 313    * @since 4.0
 314    */
 315   
 316    public void forgetPage(String name);
 317   
 318    /**
 319    * Returns the central {@link org.apache.tapestry.services.Infrastructure}&nbsp;object used to
 320    * manage the processing of the request.
 321    *
 322    * @since 4.0
 323    */
 324   
 325    public Infrastructure getInfrastructure();
 326   
 327    /**
 328    * Returns the {@link RequestContext}. This is provided to ease the upgrade from Tapestry 3.0.
 329    *
 330    * @deprecated To be removed in 4.1.
 331    */
 332   
 333    public RequestContext getRequestContext();
 334   
 335    /**
 336    * Returns the provided string, possibly modified (with an appended suffix) to make it unique.
 337    *
 338    * @param baseId
 339    * the base id from which to generate the unique string.
 340    * @return baseId, or baseId with a suffix appended (if the method has been previously invoked
 341    * with the same baseId).
 342    */
 343   
 344    public String getUniqueId(String baseId);
 345   
 346    /**
 347    * Sends a redirect to the client web browser. This is currently a convinience for constructing
 348    * and throwing a {@link RedirectException}, but may change in a later release.
 349    *
 350    * @since 4.0
 351    * @throws RedirectException
 352    */
 353   
 354    public void sendRedirect(String URL);
 355    }