- All Implemented Interfaces:
- Direct Known Subclasses:
public abstract class Page extends MarkupContainer implements IRequestablePage, IQueueRegionAbstract base class for pages. As a
MarkupContainersubclass, a Page can contain a component hierarchy and markup in some markup language such as HTML. Users of the framework should not attempt to subclass Page directly. Instead they should subclass a subclass of Page that is appropriate to the markup type they are using, such as
WebPage(for HTML markup).
Page has the following differences to
Components main concepts:
- Identity - Page numerical identifiers start at 0 for each
Sessionand increment for each new page. This numerical identifier is used as the component identifier accessible via
- Construction - When a page is constructed, it is automatically registerd with the
Pages can be constructed with any constructor like any other component, but if you wish to link to a Page using a URL that is "bookmarkable" (which implies that the URL will not have any session information encoded in it, and that you can call this page directly without having a session first directly from your browser), you need to implement your Page with a no-arg constructor or with a constructor that accepts a
PageParametersargument (which wraps any query string parameters for a request). In case the page has both constructors, the constructor with PageParameters will be used.
- Versioning - Pages support the browser's back button when versioning is enabled via
Component.setVersioned(boolean). By default all pages are versioned if not configured differently in
Constructors Modifier Constructor Description
PageParametersparameter will be stored in this page and then those parameters will be used to create stateless links to this bookmarkable page.
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
componentChanged(Component component, MarkupContainer parent)This method will be called for all components that are changed on the page So also auto components or components that are not versioned.
componentRendered(Component component)Adds a component to the set of rendered components.
detachModels()Detaches any attached models referenced by this page.
dirty(boolean isInitialization)Mark this page as modified in the session.
getAutoIndex()THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
getId()Gets the id of this component.
getMarkupType()Get the type of associated markup for this component.
Class<? extends Page>
PageParametersobject that was used to construct this page.
getPageReference()Gets page instance's unique identifier
getRenderCount()Returns the number of times this page has been rendered.
getStatelessHint()Returns whether the page should try to be stateless.
internalOnModelChanged()THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
isBookmarkable()Bookmarkable page can be instantiated using a bookmarkable URL.
isErrorPage()Override this method and return true if your page is used to display Wicket errors.
isPageStateless()Gets whether the page is stateless.
onAfterRender()Called immediately after a component and all its children have been rendered, regardless of any exception.
onBeforeRender()Called on all visible components before any component is rendered.
onConfigure()Called on all components before any component is rendered.
onDetach()Called to allow a component to detach resources after use.
onInitialize()This method is meant to be used as an alternative to initialize components.
onRender()Implementation that renders this component.
renderPage()Renders the page
setFreezePageId(boolean freeze)Sets whether or not the page is allowed to change its page id.
setNumericId(int id)THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
setStatelessHint(boolean value)Sets whether the page should try to be stateless.
setWasCreatedBookmarkable(boolean wasCreatedBookmarkable)THIS METHOD IS NOT PART OF WICKET API.
toString()Get the string representation of this container.
wasCreatedBookmarkable()Checks if this page was created using one of its bookmarkable constructors
wasRendered(Component component)THIS METHOD IS NOT PART OF THE WICKET PUBLIC API.
Methods inherited from class org.apache.wicket.MarkupContainer
add, addDequeuedComponent, addOrReplace, autoAdd, canDequeueTag, contains, dequeue, dequeue, dequeuePreamble, findChildComponent, findComponentToDequeue, get, getAssociatedMarkup, getAssociatedMarkupStream, getMarkup, getRegionMarkup, internalAdd, internalInitialize, iterator, iterator, newDequeueContext, onComponentTagBody, queue, remove, remove, removeAll, renderAll, renderAssociatedMarkup, renderAssociatedMarkup, renderNext, replace, setDefaultModel, size, stream, streamChildren, toString, visitChildren, visitChildren
Methods inherited from class org.apache.wicket.Component
add, addStateChange, beforeRender, canCallListener, canCallListenerAfterExpiry, checkComponentTag, checkComponentTagAttribute, checkHierarchyChange, clearOriginalDestination, configure, continueToOriginalDestination, createConverter, debug, detach, detachModel, determineVisibility, error, exceptionMessage, fatal, findMarkupStream, findPage, findParent, findParentWithAssociatedMarkup, getAjaxRegionMarkupId, getApplication, getBehaviorById, getBehaviorId, getBehaviors, getBehaviors, getClassRelativePath, getConverter, getDefaultModel, getDefaultModelObject, getDefaultModelObjectAsString, getDefaultModelObjectAsString, getEscapeModelStrings, getFeedbackMessages, getFlag, getInnermostModel, getInnermostModel, getLocale, getLocalizer, getMarkup, getMarkupAttributes, getMarkupId, getMarkupId, getMarkupIdFromMarkup, getMarkupIdImpl, getMarkupSourcingStrategy, getMarkupTag, getMetaData, getModelComparator, getOutputMarkupId, getOutputMarkupPlaceholderTag, getPage, getPageRelativePath, getParent, getPath, getRenderBodyOnly, getRequest, getRequestCycle, getRequestFlag, getResponse, getSession, getString, getString, getString, getStyle, getVariation, hasBeenRendered, hasErrorMessage, hasFeedbackMessage, info, initModel, internalRenderComponent, internalRenderHead, isActionAuthorized, isAuto, isBehaviorAccepted, isEnableAllowed, isEnabled, isEnabledInHierarchy, isIgnoreAttributeModifier, isInitialized, isRenderAllowed, isRendering, isStateless, isVersioned, isVisibilityAllowed, isVisible, isVisibleInHierarchy, markRendering, modelChanged, modelChanging, newMarkupSourcingStrategy, onComponentTag, onEvent, onModelChanged, onModelChanging, onReAdd, onRemove, redirectToInterceptPage, remove, remove, render, renderComponentTag, rendered, renderHead, renderPart, renderPlaceholderTag, replaceComponentTagBody, replaceWith, sameInnermostModel, sameInnermostModel, send, setAuto, setDefaultModelObject, setEnabled, setEscapeModelStrings, setFlag, setIgnoreAttributeModifier, setMarkup, setMarkupId, setMarkupIdImpl, setMetaData, setOutputMarkupId, setOutputMarkupPlaceholderTag, setParent, setRenderBodyOnly, setResponsePage, setResponsePage, setResponsePage, setVersioned, setVisibilityAllowed, setVisible, success, urlFor, urlFor, urlFor, urlForListener, urlForListener, visitParents, visitParents, warn, wrap
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.apache.wicket.IQueueRegion
dequeue, getRegionMarkup, newDequeueContext
Methods inherited from interface org.apache.wicket.request.component.IRequestableComponent
canCallListenerAfterExpiry, detach, get, getBehaviorById, getBehaviorId, getPage, getPageRelativePath
model- See Component
- See Also:
public PageParameters getPageParameters()The
PageParametersobject that was used to construct this page. This will be used in creating stateless/bookmarkable links to this page
public final void componentRendered(Component component)Adds a component to the set of rendered components.
component- The component that was rendered
public void detachModels()Detaches any attached models referenced by this page.
protected void onConfigure()Called on all components before any component is rendered. This method should be used to configure such things as visibility and enabled flags.
Overrides must call
super.onConfigure(), usually before any other code
NOTE: Component hierarchy should not be modified inside this method, instead it should be done in
NOTE: Why this method is preferrable to directly overriding
Component.isEnabled()? Because those methods are called multiple times even for processing of a single request. If they contain expensive logic they can slow down the response time of the entire page. Further, overriding those methods directly on form components may lead to inconsistent or unexpected state depending on when those methods are called in the form processing workflow. It is a better practice to push changes to state rather than pull.
NOTE: If component's visibility or another property depends on another component you may call
other.isVisible()as mentioned in
NOTE: Why should
Component.onBeforeRender()not be used for this? Because if a component's visibility is controlled inside
Component.onBeforeRender(), once invisible the component will never become visible again.
public boolean setFreezePageId(boolean freeze)Sets whether or not the page is allowed to change its page id. Implementations of this interface usually change their page id once a change to the data structure is made and historical record of the current state needs to be kept (usually to be accessible via the back button). Keeping a historical record is usually achieved by simply incrementing the page id to the next unique number, so when the implementation is stored it is done so in a new slot. This method is useful when for some reason we do not want the implementation to change its page id under any circumstances. One concrete example is an AJAX request. Suppose the page with id 10 was written out with callbacks pointing to id 10. Suppose that the user executed some AJAX callbacks which have changed the page id to 15. Now, the user clicks a non-AJAX link that was never updated by an AJAX update and still points to id 10 - which causes the state of the page to be rolled back - which is usually undesirable as all changes made to the page by AJAX requests are lost. So, instead, whatever is invoking the execution of the AJAX request on the page can use this method to tell the page to not update its page id thereby solving the problem.
public void dirty(boolean isInitialization)Mark this page as modified in the session. If versioning is supported then a new version of the page will be stored in
isInitialization- a flag whether this is a page instantiation
protected void onInitialize()This method is meant to be used as an alternative to initialize components. Usually the component's constructor is used for this task, but sometimes a component cannot be initialized in isolation, it may need to access its parent component or its markup in order to fully initialize. This method is invoked once per component's lifecycle when a path exists from this component to the
Pagethus providing the component with an atomic callback when the component's environment is built out.
Overrides must call super#
Component.onInitialize(). Usually this should be the first thing an override does, much like a constructor.
Parent containers are guaranteed to be initialized before their children
It is safe to use
Component.getPage()in this method
NOTE:The timing of this call is not precise, the contract is that it is called sometime before
public final int getAutoIndex()THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL IT. Get a page unique number, which will be increased with each call.
- A page unique number
getIdGets the id of this component.
public final long getSizeInBytes()
public final boolean getStatelessHint()Returns whether the page should try to be stateless. To be stateless, getStatelessHint() of every component on page (and it's behavior) must return true and the page must be bookmarkable.
public final String hierarchyAsString()
- This page's component hierarchy as a string
public boolean isBookmarkable()Bookmarkable page can be instantiated using a bookmarkable URL.
public boolean isErrorPage()Override this method and return true if your page is used to display Wicket errors. This can help the framework prevent infinite failure loops.
- True if this page is intended to display an error to the end user.
public final boolean isPageStateless()Gets whether the page is stateless. Components on stateless page must not render any stateful urls, and components on stateful page must not render any stateless urls. Stateful urls are urls, which refer to a certain (current) page instance.
public final void setNumericId(int id)THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL. Set the id for this Page. This method is called by PageMap when a Page is added because the id, which is assigned by PageMap, is not known until this time.
id- The id
public final Page setStatelessHint(boolean value)Sets whether the page should try to be stateless. To be stateless, getStatelessHint() of every component on page (and it's behavior) must return true and the page must be bookmarkable.
value- whether the page should try to be stateless
toStringGet the string representation of this container.
protected void componentChanged(Component component, MarkupContainer parent)This method will be called for all components that are changed on the page So also auto components or components that are not versioned. If the parent is given that it was a remove or add from that parent of the given component. else it was just a internal property change of that component.
protected final void internalOnModelChanged()THIS METHOD IS NOT PART OF THE WICKET PUBLIC API. DO NOT CALL OR OVERRIDE.
protected void onBeforeRender()Called on all visible components before any component is rendered.
NOTE: If you override this, you *must* call super.onBeforeRender() within your implementation. Because this method is responsible for cascadingChanges to the component tree can be made only before calling super.onBeforeRender().
Component.onBeforeRender()call to its children it is strongly recommended that super call is made at the end of the override.
protected void onAfterRender()Called immediately after a component and all its children have been rendered, regardless of any exception.
protected void onDetach()Called to allow a component to detach resources after use. Overrides of this method MUST call the super implementation, the most logical place to do this is the last line of the override method.
protected void onRender()Implementation that renders this component.
public MarkupType getMarkupType()Description copied from class:
MarkupContainerGet the type of associated markup for this component. The markup type for a component is independent of whether or not the component actually has an associated markup resource file (which is determined at runtime).
- The type of associated markup for this component (for example, "html", "wml" or "vxml"). If there is no markup type for a component, null may be returned, but this means that no markup can be loaded for the class. Null is also returned if the component, or any of its parents, has not been added to a Page.
public PageReference getPageReference()Gets page instance's unique identifier
- instance unique identifier
public int getPageId()
public int getRenderCount()Description copied from interface:
IRequestablePageReturns the number of times this page has been rendered. The number will be appended to request listener links in order to prevent invoking listeners from staled page version.
For example, the same page might have been rendered in two separate tabs. Page render doesn't change page id, but it can modify component hierarchy. Request listeners on such page should only work in tab where the page was rendered most recently.
public final void setWasCreatedBookmarkable(boolean wasCreatedBookmarkable)THIS METHOD IS NOT PART OF WICKET API. DO NOT USE! Sets the flag that determines whether or not this page was created using one of its bookmarkable constructors
public final boolean wasCreatedBookmarkable()Checks if this page was created using one of its bookmarkable constructors
public void renderPage()Description copied from interface:
IRequestablePageRenders the page