org.apache.tapestry.contrib.link
Class FormLinkRenderer

java.lang.Object
  org.apache.tapestry.link.DefaultLinkRenderer
      org.apache.tapestry.contrib.link.FormLinkRenderer

All Implemented Interfaces:

ILinkRenderer

public class FormLinkRenderer
extends DefaultLinkRenderer

A link renderer that ensures that the generated link uses POST instead of GET request and is therefore no longer limited in size.

Theoretically, browsers should support very long URLs, but in practice they often start behaving strangely if the URLs are more than 256 characters. This renderer uses JavaScript to generate forms containing the requested link parameters and then "post" them when the link is selected. As a result, the data is sent to the server using a POST request with a very short URL and there is no longer a limitation in the size of the parameters.

In short, simply add the following parameter to your DirectLink, ExternalLink, or other such link components:

 renderer = "ognl: @org.apache.tapestry.contrib.link.FormLinkRenderer@RENDERER"
 

and they will automatically start using POST rather than GET requests. Their parameters will no longer be limited in size.

Since:

4.0

Author:

mb

Field Summary

static ILinkRenderer

RENDERER A public singleton instance of the FormLinkRenderer.

Fields inherited from class org.apache.tapestry.link.DefaultLinkRenderer

SHARED_INSTANCE

Constructor Summary

FormLinkRenderer()

Method Summary

void	renderLink(IMarkupWriter writer, IRequestCycle cycle, ILinkComponent linkComponent) Renders the link, taking into account whether the link is disabled.

Methods inherited from class org.apache.tapestry.link.DefaultLinkRenderer

afterBodyRender, beforeBodyRender, constructURL, getElement, getHasBody, getTargetAttribute, getUrlAttribute, renderAsyncParams

Methods inherited from class java.lang.Object

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

Field Detail

RENDERER

public static final ILinkRenderer RENDERER

A public singleton instance of the FormLinkRenderer.

Since the FormLinkRenderer is stateless, this instance can serve all links within your application without interference.

Constructor Detail

FormLinkRenderer

public FormLinkRenderer()

Method Detail

renderLink

public void renderLink(IMarkupWriter writer,
                       IRequestCycle cycle,
                       ILinkComponent linkComponent)

Description copied from interface: ILinkRenderer

Renders the link, taking into account whether the link is disabled. This is complicated by the fact that the rendering of the body must be done within a nested writer, since the Link component will not render its tag until after its body renders (to allow for any wrapped components that need to write event handlers for the link).

The renderer is expected to call back into the link component to handle any informal parameters, and to handle events output.

Specified by:

renderLink in interface ILinkRenderer

Overrides:

renderLink in class DefaultLinkRenderer