org.apache.wicket.ajax
Class AjaxRequestTarget

java.lang.Object
  org.apache.wicket.ajax.AjaxRequestTarget

All Implemented Interfaces:

IPageClassRequestHandler, IPageRequestHandler, IRequestHandler

public class AjaxRequestTarget
extends Object
implements IPageRequestHandler

A request target that produces ajax response envelopes used on the client side to update component markup as well as evaluate arbitrary javascript.

A component whose markup needs to be updated should be added to this target via AjaxRequestTarget#addComponent(Component) method. Its body will be rendered and added to the envelope when the target is processed, and refreshed on the client side when the ajax response is received.

It is important that the component whose markup needs to be updated contains an id attribute in the generated markup that is equal to the value retrieved from Component#getMarkupId(). This can be accomplished by either setting the id attribute in the html template, or using an attribute modifier that will add the attribute with value Component#getMarkupId() to the tag ( such as MarkupIdSetter )

Any javascript that needs to be evaluated on the client side can be added using AjaxRequestTarget#append/prependJavaScript(String). For example, this feature can be useful when it is desirable to link component update with some javascript effects.

The target provides a listener interface AjaxRequestTarget.IListener that can be used to add code that responds to various target events by adding listeners via addListener(org.apache.wicket.ajax.AjaxRequestTarget.IListener)

Since:

1.2

Author:

Igor Vaynberg (ivaynberg), Eelco Hillenius

Nested Class Summary

static interface	AjaxRequestTarget.IJavaScriptResponse An ajax javascript response that allows users to add javascript to be executed on the client side
static interface	AjaxRequestTarget.IListener An AjaxRequestTarget listener that can be used to respond to various target-related events
static interface	AjaxRequestTarget.ITargetRespondListener Components can implement this interface to get a notification when AjaxRequestTarget begins to respond.

Constructor Summary

AjaxRequestTarget(Page page)
Constructor

Method Summary

void	add(Component... components) Adds components to the list of components to be rendered
void	add(Component component, String markupId) Adds a component to the list of components to be rendered
void	addChildren(MarkupContainer parent, Class<?> childCriteria) Visits all children of the specified parent container and adds them to the target if they are of same type as childCriteria
void	addComponent(Component... components) Deprecated. use add(Component...) instead
void	addComponent(Component component, String markupId) Deprecated. use add(Component...) instead
void	addListener(AjaxRequestTarget.IListener listener) Adds a listener to this target
void	appendJavaScript(CharSequence javascript) Adds javascript that will be evaluated on the client side after components are replaced
void	detach(IRequestCycle requestCycle)
protected String	encode(CharSequence str) Encodes a string so it is safe to use inside CDATA blocks
boolean	equals(Object obj)
void	focusComponent(Component component) Sets the focus in the browser to the given component.
static AjaxRequestTarget	get() Static method that returns current AjaxRequestTarget or null of no AjaxRequestTarget is available.
Collection<? extends Component>	getComponents() Returns an unmodifiable collection of all components added to this target
protected String	getEncodingName()
IHeaderResponse	getHeaderResponse() Returns the header response associated with current AjaxRequestTarget.
String	getLastFocusedElementId() Returns the HTML id of the last focused element.
Page	getPage() Returns the page
Class<? extends IRequestablePage>	getPageClass() Returns the page class
PageParameters	getPageParameters()
int	hashCode()
protected boolean	needsEncoding(CharSequence str)
void	prependJavaScript(CharSequence javascript) Adds javascript that will be evaluated on the client side before components are replaced
void	registerRespondListener(AjaxRequestTarget.ITargetRespondListener listener) Register the given respond listener.
void	respond(IRequestCycle requestCycle)
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

AjaxRequestTarget

public AjaxRequestTarget(Page page)

Constructor

Parameters:

page -

Method Detail

getPage

public Page getPage()

Description copied from interface: IPageRequestHandler

Returns the page

Specified by:

getPage in interface IPageRequestHandler

Returns:

page instance

See Also:

IPageRequestHandler.getPage()

addListener

public void addListener(AjaxRequestTarget.IListener listener)

Adds a listener to this target

Parameters:

listener -

addChildren

public final void addChildren(MarkupContainer parent,
                              Class<?> childCriteria)

Visits all children of the specified parent container and adds them to the target if they are of same type as childCriteria

Parameters:

parent -

childCriteria -

addComponent

@Deprecated
public void addComponent(Component... components)

Deprecated. use add(Component...) instead

Adds components to the list of components to be rendered

Parameters:

components - components to be rendered

add

public void add(Component... components)

Adds components to the list of components to be rendered

Parameters:

components - components to be rendered

addComponent

@Deprecated
public final void addComponent(Component component,
                                          String markupId)

Deprecated. use add(Component...) instead

Adds a component to the list of components to be rendered

Parameters:

markupId - id of client-side dom element that will be updated

component - component to be rendered

add

public final void add(Component component,
                      String markupId)

Adds a component to the list of components to be rendered

Parameters:

markupId - id of client-side dom element that will be updated

component - component to be rendered

getComponents

public final Collection<? extends Component> getComponents()

Returns an unmodifiable collection of all components added to this target

Returns:

unmodifiable collection of all components added to this target

focusComponent

public final void focusComponent(Component component)

Sets the focus in the browser to the given component. The markup id must be set. If the component is null the focus will not be set to any component.

Parameters:

component - The component to get the focus or null.

appendJavaScript

public final void appendJavaScript(CharSequence javascript)

Adds javascript that will be evaluated on the client side after components are replaced

Parameters:

javascript -

detach

public void detach(IRequestCycle requestCycle)

Specified by:

detach in interface IRequestHandler

See Also:

IRequestHandler.detach(org.apache.wicket.request.IRequestCycle)

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

See Also:

Object.equals(java.lang.Object)

hashCode

public int hashCode()

Overrides:

hashCode in class Object

See Also:

Object.hashCode()

prependJavaScript

public final void prependJavaScript(CharSequence javascript)

Adds javascript that will be evaluated on the client side before components are replaced

Parameters:

javascript -

registerRespondListener

public void registerRespondListener(AjaxRequestTarget.ITargetRespondListener listener)

Register the given respond listener. The listener's AjaxRequestTarget.ITargetRespondListener.onTargetRespond(AjaxRequestTarget) method will be invoked when the AjaxRequestTarget starts to respond.

Parameters:

listener -

respond

public final void respond(IRequestCycle requestCycle)

Specified by:

respond in interface IRequestHandler

See Also:

IRequestHandler.respond(org.apache.wicket.request.IRequestCycle)

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()

encode

protected String encode(CharSequence str)

Encodes a string so it is safe to use inside CDATA blocks

Parameters:

str -

Returns:

encoded string

getEncodingName

protected String getEncodingName()

Returns:

name of encoding used to possibly encode the contents of the CDATA blocks

needsEncoding

protected boolean needsEncoding(CharSequence str)

Parameters:

str -

Returns:

true if string needs to be encoded, false otherwise

getHeaderResponse

public IHeaderResponse getHeaderResponse()

Returns the header response associated with current AjaxRequestTarget. Beware that only renderOnDomReadyJavaScript and renderOnLoadJavaScript can be called outside the renderHeader(IHeaderResponse response) method. Calls to other render** methods will result in the call failing with a debug-level log statement to help you see why it failed.

Returns:

header response

get

public static AjaxRequestTarget get()

Static method that returns current AjaxRequestTarget or null of no AjaxRequestTarget is available.

Returns:

AjaxRequestTarget instance if current request is an Ajax request, null otherwise.

getLastFocusedElementId

public String getLastFocusedElementId()

Returns the HTML id of the last focused element.

Returns:

markup id of last focused element, null if none

getPageClass

public Class<? extends IRequestablePage> getPageClass()

Description copied from interface: IPageClassRequestHandler

Returns the page class

Specified by:

getPageClass in interface IPageClassRequestHandler

Returns:

page class

getPageParameters

public PageParameters getPageParameters()

Specified by:

getPageParameters in interface IPageClassRequestHandler

Returns:

page parameters