| // Copyright 2004, 2005 The Apache Software Foundation |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package org.apache.tapestry; |
| |
| import org.apache.tapestry.engine.IEngineService; |
| import org.apache.tapestry.engine.IMonitor; |
| import org.apache.tapestry.request.RequestContext; |
| import org.apache.tapestry.services.Infrastructure; |
| |
| /** |
| * Controller object that manages a single request cycle. A request cycle is one 'hit' on the web |
| * server. In the case of a Tapestry application, this will involve: |
| * <ul> |
| * <li>Responding to the URL by finding an {@link IEngineService}object |
| * <li>Determining the result page |
| * <li>Renderring the result page |
| * <li>Releasing any resources |
| * </ul> |
| * <p> |
| * Mixed in with this is: |
| * <ul> |
| * <li>Exception handling |
| * <li>Loading of pages and templates from resources |
| * <li>Tracking changes to page properties, and restoring pages to prior states |
| * <li>Pooling of page objects |
| * </ul> |
| * <p> |
| * A request cycle is broken up into two phases. The <em>rewind</em> phase is optional, as it tied |
| * to {@link org.apache.tapestry.link.ActionLink}or {@link org.apache.tapestry.form.Form} |
| * components. In the rewind phase, a previous page render is redone (discarding output) until a |
| * specific component of the page is reached. This rewinding ensures that the page is restored to |
| * the exact state it had when the URL for the request cycle was generated, taking into account the |
| * dynamic nature of the page ({@link org.apache.tapestry.components.Foreach}, |
| * {@link org.apache.tapestry.components.Conditional}, etc.). Once this component is reached, it |
| * can notify its {@link IActionListener}. The listener has the ability to update the state of any |
| * pages and select a new result page. |
| * <p> |
| * Following the rewind phase is the <em>render</em> phase. During the render phase, a page is |
| * actually rendered and output sent to the client web browser. |
| * |
| * @author Howard Lewis Ship |
| */ |
| |
| public interface IRequestCycle |
| { |
| /** |
| * Invoked after the request cycle is no longer needed, to release any resources it may have. |
| * This includes releasing any loaded pages back to the page source. |
| */ |
| |
| public void cleanup(); |
| |
| /** |
| * Passes the String through |
| * {@link javax.servlet.http.HttpServletResponse#encodeURL(java.lang.String)}, which ensures |
| * that the session id is encoded in the URL (if necessary). |
| */ |
| |
| public String encodeURL(String URL); |
| |
| /** |
| * Returns the engine which is processing this request cycle. |
| */ |
| |
| public IEngine getEngine(); |
| |
| /** |
| * Retrieves a previously stored attribute, returning null if not found. Attributes allow |
| * components to locate each other; primarily they allow a wrapped component to locate a |
| * component which wraps it. Attributes are cleared at the end of the render (or rewind). |
| */ |
| |
| public Object getAttribute(String name); |
| |
| public IMonitor getMonitor(); |
| |
| /** |
| * Returns the next action id. ActionLink ids are used to identify different actions on a page |
| * (URLs that are related to dynamic page state). |
| * |
| * @deprecated To be removed in release 4.1 with no replacement. |
| * @see #getUniqueId(String) |
| */ |
| |
| public String getNextActionId(); |
| |
| /** |
| * Identifies the active page, the page which will ultimately render the response. |
| */ |
| |
| public IPage getPage(); |
| |
| /** |
| * Returns the page with the given name. If the page has been previously loaded in the current |
| * request cycle, that page is returned. Otherwise, the engine's page loader is used to load the |
| * page. |
| * |
| * @throws PageNotFoundException |
| * if the page does not exist. |
| * @see org.apache.tapestry.engine.IPageSource#getPage(IRequestCycle, String, IMonitor) |
| */ |
| |
| public IPage getPage(String name); |
| |
| /** |
| * Returns true if the context is being used to rewind a prior state of the page. This is only |
| * true when there is a target action id. |
| */ |
| |
| public boolean isRewinding(); |
| |
| /** |
| * Checks to see if the current action id matches the target action id. Returns true only if |
| * they match. Returns false if there is no target action id (that is, during page rendering). |
| * <p> |
| * If theres a match on action id, then the component is compared against the target component. |
| * If there's a mismatch then a {@link StaleLinkException}is thrown. |
| */ |
| |
| public boolean isRewound(IComponent component) throws StaleLinkException; |
| |
| /** |
| * Removes a previously stored attribute, if one with the given name exists. |
| */ |
| |
| public void removeAttribute(String name); |
| |
| /** |
| * Renders the given page. Applications should always use this method to render the page, rather |
| * than directly invoking {@link IPage#render(IMarkupWriter, IRequestCycle)}since the request |
| * cycle must perform some setup before rendering. |
| */ |
| |
| public void renderPage(IMarkupWriter writer); |
| |
| /** |
| * Rewinds a page and executes some form of action when the component with the specified action |
| * id is reached. |
| * |
| * @see IAction |
| * @see org.apache.tapestry.link.ActionLink |
| * @deprecated To be removed in 4.1 with no replacement. |
| */ |
| |
| public void rewindPage(String targetActionId, IComponent targetComponent); |
| |
| /** |
| * Allows a temporary object to be stored in the request cycle, which allows otherwise unrelated |
| * objects to communicate. This is similar to <code>HttpServletRequest.setAttribute()</code>, |
| * except that values can be changed and removed as well. |
| * <p> |
| * This is used by components to locate each other. A component, such as |
| * {@link org.apache.tapestry.html.Body}, will write itself under a well-known name into the |
| * request cycle, and components it wraps can locate it by that name. |
| * <p> |
| * Attributes are cleared at the end of each render or rewind phase. |
| */ |
| |
| public void setAttribute(String name, Object value); |
| |
| /** |
| * Invoked just before rendering the response page to get all |
| * {@link org.apache.tapestry.engine.IPageRecorder page recorders}touched in this request cycle |
| * to commit their changes (save them to persistant storage). |
| * |
| * @see org.apache.tapestry.engine.IPageRecorder#commit() |
| */ |
| |
| public void commitPageChanges(); |
| |
| /** |
| * Returns the service which initiated this request cycle. |
| * |
| * @since 1.0.1 |
| */ |
| |
| public IEngineService getService(); |
| |
| /** |
| * Used by {@link IForm forms}to perform a <em>partial</em> rewind so as to respond to the |
| * form submission (using the direct service). |
| * <p> |
| * Note: the targetActionId parameter was removed in release 4.0. |
| * |
| * @since 1.0.2 |
| */ |
| |
| public void rewindForm(IForm form); |
| |
| /** |
| * Much like {@link #forgetPage(String)}, but the page stays active and can even record |
| * changes, until the end of the request cycle, at which point it is discarded (and any recorded |
| * changes are lost). This is used in certain rare cases where a page has persistent state but |
| * is being renderred "for the last time". |
| * |
| * @since 2.0.2 |
| * @deprecated To be removed in 4.1. Use {@link #forgetPage(String)}. |
| */ |
| |
| public void discardPage(String name); |
| |
| /** |
| * Invoked by a {@link IEngineService service} to store an array of application-specific |
| * parameters. These can later be retrieved (typically, by an application-specific listener |
| * method) by invoking {@link #getServiceParameters()}. |
| * <p> |
| * Through release 2.1, parameters was of type String[]. This is an incompatible change in 2.2. |
| * |
| * @see org.apache.tapestry.engine.DirectService |
| * @since 2.0.3 |
| * @deprecated To be removed in 4.1. Use {@link #setListenerParameters(Object[])}instead. |
| */ |
| |
| public void setServiceParameters(Object[] parameters); |
| |
| /** |
| * Invoked by a {@link IEngineService service} to store an array of application-specific |
| * parameters. These can later be retrieved (typically, by an application-specific listener |
| * method) by invoking {@link #getListenerParameters()}. |
| * |
| * @see org.apache.tapestry.engine.DirectService |
| * @since 4.0 |
| */ |
| public void setListenerParameters(Object[] parameters); |
| |
| /** |
| * Returns parameters previously stored by {@link #setServiceParameters(Object[])}. |
| * <p> |
| * Through release 2.1, the return type was String[]. This is an incompatible change in 2.2. |
| * |
| * @since 2.0.3 |
| * @deprecated To be removed in 4.1. Use {@link #getListenerParameters()}instead. |
| */ |
| |
| public Object[] getServiceParameters(); |
| |
| /** |
| * Returns parameters previously stored by {@link #setListenerParameters(Object[])}. |
| * |
| * @since 4.0 |
| */ |
| |
| public Object[] getListenerParameters(); |
| |
| /** |
| * A convienience for invoking {@link #activate(IPage)}. Invokes {@link #getPage(String)}to |
| * get an instance of the named page. |
| * |
| * @since 3.0 |
| */ |
| |
| public void activate(String name); |
| |
| /** |
| * Sets the active page for the request. The active page is the page which will ultimately |
| * render the response. The activate page is typically set by the {@link IEngineService service}. |
| * Frequently, the active page is changed (from a listener method) to choose an alternate page |
| * to render the response). |
| * <p> |
| * {@link IPage#validate(IRequestCycle)}is invoked on the page to be activated. |
| * {@link PageRedirectException}is caught and the page specified in the exception will be the |
| * active page instead (that is, a page may "pass the baton" to another page using the |
| * exception). The new page is also validated. This continues until a page does not throw |
| * {@link PageRedirectException}. |
| * <p> |
| * Validation loops can occur, where page A redirects to page B and then page B redirects back |
| * to page A (possibly with intermediate steps). This is detected and results in an |
| * {@link ApplicationRuntimeException}. |
| * |
| * @since 3.0 |
| */ |
| public void activate(IPage page); |
| |
| /** |
| * Returns a query parameter value, or null if not provided in the request. If multiple values |
| * are provided, returns the first value. |
| * |
| * @since 4.0 |
| */ |
| public String getParameter(String name); |
| |
| /** |
| * Returns all query parameter values for the given name. Returns null if no values were |
| * provided. |
| * |
| * @since 4.0 |
| */ |
| public String[] getParameters(String name); |
| |
| /** |
| * Converts a partial URL into an absolute URL. Prefixes the provided URL with servlet context |
| * path (if any), then expands it to a full URL by prepending with the scheme, server and port |
| * (determined from the current {@link org.apache.tapestry.web.WebRequest request}. |
| * |
| * @since 4.0 |
| */ |
| |
| public String getAbsoluteURL(String partialURL); |
| |
| /** |
| * Forgets any stored changes to the specified page. If the page has already been loaded (and |
| * rolled back) then the loaded page instance is not affected; if the page is only loaded |
| * subsequently, the page instance will not see any persisted property changes. |
| * |
| * @since 4.0 |
| */ |
| |
| public void forgetPage(String name); |
| |
| /** |
| * Returns the central {@link org.apache.tapestry.services.Infrastructure} object used to |
| * manage the processing of the request. |
| * |
| * @since 4.0 |
| */ |
| |
| public Infrastructure getInfrastructure(); |
| |
| /** |
| * Returns the {@link RequestContext}. This is provided to ease the upgrade from Tapestry 3.0. |
| * |
| * @deprecated To be removed in 4.1. |
| */ |
| |
| public RequestContext getRequestContext(); |
| |
| /** |
| * Returns the provided string, possibly modified (with an appended suffix) to make it unique. |
| * |
| * @param baseId |
| * the base id from which to generate the unique string. |
| * @return baseId, or baseId with a suffix appended (if the method has been previously invoked |
| * with the same baseId). |
| */ |
| |
| public String getUniqueId(String baseId); |
| |
| /** |
| * Sends a redirect to the client web browser. This is currently a convinience for constructing |
| * and throwing a {@link RedirectException}, but may change in a later release. |
| * |
| * @since 4.0 |
| * @throws RedirectException |
| */ |
| |
| public void sendRedirect(String URL); |
| } |
