Clover coverage report - Code Coverage for tapestry release 4.0-beta-2
Coverage timestamp: Sat Jul 9 2005 22:02:17 EDT
file stats: LOC: 346   Methods: 0
NCLOC: 39   Classes: 1
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 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.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}&nbsp;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}&nbsp;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}&nbsp;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    }