Package org.apache.wicket.markup.head

Interface IHeaderResponse

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable

All Known Implementing Classes:

DecoratingHeaderResponse, FilteringHeaderResponse, HeaderResponse, JavaScriptDeferHeaderResponse, JavaScriptFilteredIntoFooterHeaderResponse, ResourceAggregator

public interface IHeaderResponse
extends java.io.Closeable

Interface that is used to render header elements (usually javascript and CSS references). Implementation of this interface is responsible for filtering duplicate contributions (so that for example the same javascript is not loaded twice) during the same request.

Author:

Matej Knopp

Method Summary

Modifier and Type	Method	Description
void	close()	Mark Header rendering is completed and subsequent usage will be ignored.
org.apache.wicket.request.Response	getResponse()	Returns the response that can be used to write arbitrary text to the head section.
boolean	isClosed()
void	markRendered(java.lang.Object object)	Marks the given object as rendered.
void	render(HeaderItem item)	Renders the given HeaderItem to the response if none of the tokens of the item has been rendered before.
boolean	wasRendered(java.lang.Object object)	Returns whether the given object has been marked as rendered.

Method Detail

render

void render(HeaderItem item)

Renders the given HeaderItem to the response if none of the tokens of the item has been rendered before.

Parameters:

item - The item to render.

markRendered

void markRendered(java.lang.Object object)

Marks the given object as rendered. The object can be anything (string, resource reference, etc...). The purpose of this function is to allow user to manually keep track of rendered items. This can be useful for items that are expensive to generate (like interpolated text).

Parameters:

object - object to be marked as rendered.

wasRendered

boolean wasRendered(java.lang.Object object)

Returns whether the given object has been marked as rendered.

• Methods renderJavaScriptReference and renderCSSReference mark the specified ResourceReference as rendered.
• Method renderJavaScript marks List of two elements (first is javascript body CharSequence and second is id) as rendered.
• Method renderString marks the whole string as rendered.
• Method markRendered can be used to mark an arbitrary object as rendered

Parameters:

object - Object that is queried to be rendered

Returns:

Whether the object has been marked as rendered during the request

getResponse

org.apache.wicket.request.Response getResponse()

Returns the response that can be used to write arbitrary text to the head section.

Note: This method is kind of dangerous as users are able to write to the output whatever they like.

Returns:

Response

close

void close()

Mark Header rendering is completed and subsequent usage will be ignored. If some kind of buffering is used internally, this action will mark that the contents has to be flushed out.

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

isClosed

boolean isClosed()

Returns:

if header rendering is completed and subsequent usage will be ignored