Package org.apache.wicket.core.request.handler

Class PageProvider

java.lang.Object

org.apache.wicket.core.request.handler.PageProvider

All Implemented Interfaces:

Serializable, IPageProvider, IClusterable

Direct Known Subclasses:

PageAndComponentProvider

public class PageProvider
extends Object
implements IPageProvider, IClusterable

Provides page instance for request handlers. Each of the constructors has just enough information to get existing or create new page instance. Requesting or creating page instance is deferred until getPageInstance() is called.

Purpose of this class is to reduce complexity of both IRequestMappers and IRequestHandlers. IRequestMapper examines the URL, gathers all relevant information about the page in the URL (combination of page id, page class, page parameters and render count), creates PageProvider object and creates a IRequestHandler instance that can use the PageProvider to access the page.

Apart from simplifying IRequestMappers and IRequestHandlers PageProvider also helps performance because creating or obtaining page from IPageManager is delayed until the IRequestHandler actually requires the page.

Author:

Matej Knopp

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
PageProvider(Class<? extends IRequestablePage> pageClass)	Creates a new page provider object.
PageProvider(Class<? extends IRequestablePage> pageClass, PageParameters pageParameters)	Creates a new page provider object.
PageProvider(Integer pageId, Class<? extends IRequestablePage> pageClass, Integer renderCount)	Creates a new page provider object.
PageProvider(Integer pageId, Class<? extends IRequestablePage> pageClass, PageParameters pageParameters, Integer renderCount)	Creates a new page provider object.
PageProvider(Integer pageId, Integer renderCount)	Creates a new page provider object.
PageProvider(IRequestablePage page)	Creates a new page provider object.

Method Summary

Modifier and Type	Method	Description
void	detach()	Detaches the page if it has been loaded (that means either PageProvider(IRequestablePage) constructor has been used or getPageInstance() has been called).
boolean	doesProvideNewPage()	Returns whether or not the page instance held by this provider has been instantiated by the provider.
Class<? extends IRequestablePage>	getPageClass()	Returns class of the page.
Integer	getPageId()	Returns the page id.
IRequestablePage	getPageInstance()	Returns page instance specified by the constructor.
PageParameters	getPageParameters()	Returns PageParameters of the page.
protected IPageSource	getPageSource()
Integer	getRenderCount()	Returns the number of times this page has been rendered.
boolean	hasPageInstance()	If this provider returns existing page, regardless if it was already created by PageProvider itself or is or can be found in the data store.
protected void	setPageParameters(PageParameters pageParameters)
void	setPageSource(IPageSource pageSource)	If the PageProvider is used outside request thread (thread that does not have application instance assigned) it is necessary to specify a IPageSource instance so that PageProvider knows how to get a page instance.
String	toString()
boolean	wasExpired()	Returns whether the provided page was expired prior to this access.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PageProvider

public PageProvider(Integer pageId,
                    Integer renderCount)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return page instance with specified id.

Parameters:

pageId -

renderCount - optional argument

PageProvider

public PageProvider(Integer pageId,
                    Class<? extends IRequestablePage> pageClass,
                    Integer renderCount)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return page instance with specified id if it exists and it's class matches pageClass. If none of these is true new page instance will be created.

Parameters:

pageId -

pageClass -

renderCount - optional argument

PageProvider

public PageProvider(Integer pageId,
                    Class<? extends IRequestablePage> pageClass,
                    PageParameters pageParameters,
                    Integer renderCount)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return page instance with specified id if it exists and it's class matches pageClass. If none of these is true new page instance will be created.

Parameters:

pageId -

pageClass -

pageParameters -

renderCount - optional argument

PageProvider

public PageProvider(Class<? extends IRequestablePage> pageClass,
                    PageParameters pageParameters)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return new instance of page with specified class.

Parameters:

pageClass -

pageParameters -

PageProvider

public PageProvider(Class<? extends IRequestablePage> pageClass)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return new instance of page with specified class.

Parameters:

pageClass -

PageProvider

public PageProvider(IRequestablePage page)

Creates a new page provider object. Upon calling of getPageInstance() this provider will return the given page instance.

Parameters:

page -

Method Detail

getPageInstance

public IRequestablePage getPageInstance()
                                 throws PageExpiredException

Description copied from interface: IPageProvider

Returns page instance specified by the constructor.

Specified by:

getPageInstance in interface IPageProvider

Returns:

page instance

Throws:

PageExpiredException - if the specified page could not have been found and the constructor used did not provide enough information to create new page instance

getPageParameters

public PageParameters getPageParameters()
                                 throws PageExpiredException

Description copied from interface: IPageProvider

Returns PageParameters of the page.

Specified by:

getPageParameters in interface IPageProvider

Returns:

page parameters

Throws:

PageExpiredException - if the specified page could not have been found and the constructor used did not provide enough information to create new page instance

hasPageInstance

public final boolean hasPageInstance()

If this provider returns existing page, regardless if it was already created by PageProvider itself or is or can be found in the data store. The only guarantee is that by calling getPageInstance() this provider will return an existing instance and no page will be created.

Specified by:

hasPageInstance in interface IPageProvider

Returns:

if provides an existing page

doesProvideNewPage

public final boolean doesProvideNewPage()

Returns whether or not the page instance held by this provider has been instantiated by the provider.

Specified by:

doesProvideNewPage in interface IPageProvider

Returns:

true iff the page instance held by this provider was instantiated by the provider

wasExpired

public boolean wasExpired()

Description copied from interface: IPageProvider

Returns whether the provided page was expired prior to this access.

Specified by:

wasExpired in interface IPageProvider

Returns:

true if the page was created after its original instance expired.

getPageClass

public Class<? extends IRequestablePage> getPageClass()
                                               throws PageExpiredException

Description copied from interface: IPageProvider

Returns class of the page.

Specified by:

getPageClass in interface IPageProvider

Returns:

page class

Throws:

PageExpiredException - if the specified page could not have been found and the constructor used did not provide enough information to create new page instance

getPageSource

protected IPageSource getPageSource()

detach

public void detach()

Detaches the page if it has been loaded (that means either PageProvider(IRequestablePage) constructor has been used or getPageInstance() has been called).

Specified by:

detach in interface IPageProvider

setPageSource

public void setPageSource(IPageSource pageSource)

If the PageProvider is used outside request thread (thread that does not have application instance assigned) it is necessary to specify a IPageSource instance so that PageProvider knows how to get a page instance.

Parameters:

pageSource -

setPageParameters

protected void setPageParameters(PageParameters pageParameters)

Parameters:

pageParameters -

getPageId

public Integer getPageId()

Description copied from interface: IPageProvider

Returns the page id.

Specified by:

getPageId in interface IPageProvider

Returns:

page id

getRenderCount

public Integer getRenderCount()

Description copied from interface: IPageProvider

Returns the number of times this page has been rendered.

Specified by:

getRenderCount in interface IPageProvider

Returns:

the number of times this page has been rendered.

toString

public String toString()

Overrides:

toString in class Object