org.apache.wicket.settings

Class RequestCycleSettings

java.lang.Object

org.apache.wicket.settings.RequestCycleSettings

public class RequestCycleSettings
extends Object

Interface for request related settings

bufferResponse (defaults to true) - True if the application should buffer responses. This does require some additional memory, but helps keep exception displays accurate because the whole rendering process completes before the page is sent to the user, thus aRequestCycleSettingsing the possibility of a partially rendered page.

renderStrategy - Sets in what way the render part of a request is handled. Basically, there are two different options:

• Direct, IRequestCycleSettings.RenderStrategy.ONE_PASS_RENDER. Everything is handled in one physical request. This is efficient, and is the best option if you want to do sophisticated clustering. It does not however, shield you from what is commonly known as the Double submit problem
• Using a redirect. This follows the pattern as described at the serverside and that is commonly known as Redirect after post. Wicket takes it one step further to do any rendering after a redirect, so that not only form submits are shielded from the double submit problem, but also the IRequestListener handlers (that could be e.g. a link that deletes a row). With this pattern, you have two options to choose from:
  • IRequestCycleSettings.RenderStrategy.REDIRECT_TO_RENDER. This option first handles the 'action' part of the request, which is either page construction (bookmarkable pages or the home page) or calling a IRequestListener handler, such as Link.onClick. When that part is done, a redirect is issued to the render part, which does all the rendering of the page and its components. Be aware that this may mean, depending on whether you access any models in the action part of the request, that attachment and detachment of some models is done twice for a request.
  • IRequestCycleSettings.RenderStrategy.REDIRECT_TO_BUFFER. This option handles both the action- and the render part of the request in one physical request, but instead of streaming the result to the browser directly, it is kept in memory, and a redirect is issued to get this buffered result (after which it is immediately removed). This option currently is the default render strategy, as it shields you from the double submit problem, while being more efficient and less error prone regarding to detachable models.
  Note: In rare cases the strategies involving redirect may lose session data! For example: if after the first phase of the strategy the server node fails without having the chance to replicate the session then the second phase will be executed on another node and the whole process will be restarted and thus anything stored in the first phase will be lost with the failure of the server node. For similar reasons it is recommended to use sticky sessions when using redirect strategies.

More documentation is available about each setting in the setter method for the property.

Author:

Jonathan Locke, Chris Turner, Eelco Hillenius, Juergen Donnerstag, Johan Compagner, Igor Vaynberg (ivaynberg), Martijn Dashorst, James Carman

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RequestCycleSettings.RenderStrategy Enum type for different render strategies

Constructor Summary

Constructors

Constructor and Description
RequestCycleSettings()

Method Summary

Methods

Modifier and Type	Method and Description
RequestCycleSettings	addResponseFilter(IResponseFilter responseFilter) Adds a response filter to the list.
boolean	getBufferResponse() Decides whether to buffer the response's headers until the end of the request processing.
int	getExceptionRetryCount()
boolean	getGatherExtendedBrowserInfo() Gets whether Wicket should try to get extensive client info by redirecting to a page that polls for client capabilities.
RequestCycleSettings.RenderStrategy	getRenderStrategy() Gets in what way the render part of a request is handled.
List<IResponseFilter>	getResponseFilters()
String	getResponseRequestEncoding() In order to do proper form parameter encoding it is important that the response and the subsequent request stipulate a common character encoding.
Duration	getTimeout() Gets the time that a request will by default be waiting for the previous request to be handled before giving up.
RequestCycleSettings	setBufferResponse(boolean bufferResponse) Sets a flag whether the application should buffer the response's headers until the end of the request processing.
RequestCycleSettings	setExceptionRetryCount(int retries) Sets how many attempts Wicket will make to render the exception request handler before giving up.
RequestCycleSettings	setGatherExtendedBrowserInfo(boolean gatherExtendedBrowserInfo) Sets whether Wicket should try to get extensive client info by redirecting to a page that polls for client capabilities.
RequestCycleSettings	setRenderStrategy(RequestCycleSettings.RenderStrategy renderStrategy) Sets in what way the render part of a request is handled.
RequestCycleSettings	setResponseRequestEncoding(String encoding) In order to do proper form parameter decoding it is important that the response and the following request have the same encoding.
RequestCycleSettings	setTimeout(Duration timeout) Sets the time that a request will by default be waiting for the previous request to be handled before giving up.

Methods inherited from class java.lang.Object

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

Constructor Detail

RequestCycleSettings

public RequestCycleSettings()

Method Detail

addResponseFilter

public RequestCycleSettings addResponseFilter(IResponseFilter responseFilter)

Adds a response filter to the list. Filters are evaluated in the order they have been added.

Parameters:

responseFilter - The IResponseFilter that is added

Returns:

this object for chaining

getBufferResponse

public boolean getBufferResponse()

Decides whether to buffer the response's headers until the end of the request processing. The buffering is needed if the application makes use of Component.setResponsePage(org.apache.wicket.request.component.IRequestablePage) or ResetResponseException

Returns:

true if the application should buffer the response's headers.

getGatherExtendedBrowserInfo

public boolean getGatherExtendedBrowserInfo()

Gets whether Wicket should try to get extensive client info by redirecting to a page that polls for client capabilities. This method is used by the default implementation of Session.getClientInfo(), so if that method is overridden, there is no guarantee this method will be taken into account.

Returns:

Whether to gather extensive client info

getRenderStrategy

public RequestCycleSettings.RenderStrategy getRenderStrategy()

Gets in what way the render part of a request is handled.

Returns:

the render strategy

getResponseFilters

public List<IResponseFilter> getResponseFilters()

Returns:

an unmodifiable list of added response filters, null if none

getResponseRequestEncoding

public String getResponseRequestEncoding()

In order to do proper form parameter encoding it is important that the response and the subsequent request stipulate a common character encoding. possible form encodings and their problems:

• application/x- www-form-urlencoded
• multipart/form-data

wicket now uses multipart/form-data for it's forms.

Returns:

The request and response encoding

getTimeout

public Duration getTimeout()

Gets the time that a request will by default be waiting for the previous request to be handled before giving up.

Returns:

The time out

setBufferResponse

public RequestCycleSettings setBufferResponse(boolean bufferResponse)

Sets a flag whether the application should buffer the response's headers until the end of the request processing. The buffering is needed if the application makes use of Component.setResponsePage(org.apache.wicket.request.component.IRequestablePage) or ResetResponseException

Parameters:

bufferResponse - true if the application should buffer response's headers.

Returns:

this object for chaining

setGatherExtendedBrowserInfo

public RequestCycleSettings setGatherExtendedBrowserInfo(boolean gatherExtendedBrowserInfo)

Sets whether Wicket should try to get extensive client info by redirecting to a page that polls for client capabilities. This method is used by the default implementation of Session.getClientInfo(), so if that method is overridden, there is no guarantee this method will be taken into account.

WARNING: though this facility should work transparently in most cases, it is recommended that you trigger the roundtrip to get the browser info somewhere where it hurts the least. The roundtrip will be triggered the first time you call Session.getClientInfo() for a session, and after the roundtrip a new request with the same info (url, post parameters) is handled. So rather than calling this in the middle of an implementation of a form submit method, which would result in the code of that method before the call to Session.getClientInfo() to be executed twice, you best call Session.getClientInfo() e.g. in a page constructor or somewhere else where you didn't do a lot of processing first.

Parameters:

gatherExtendedBrowserInfo - Whether to gather extensive client info

Returns:

this object for chaining

setRenderStrategy

public RequestCycleSettings setRenderStrategy(RequestCycleSettings.RenderStrategy renderStrategy)

Sets in what way the render part of a request is handled. Basically, there are two different options:

• Direct, ApplicationSettings.ONE_PASS_RENDER. Everything is handled in one physical request. This is efficient, and is the best option if you want to do sophisticated clustering. It does not however, shield you from what is commonly known as the Double submit problem
• Using a redirect. This follows the pattern as described at the serverside and that is commonly known as Redirect after post. Wicket takes it one step further to do any rendering after a redirect, so that not only form submits are shielded from the double submit problem, but also the IRequestListener handlers (that could be e.g. a link that deletes a row). With this pattern, you have two options to choose from:
  • ApplicationSettings.REDIRECT_TO_RENDER. This option first handles the 'action' part of the request, which is either page construction (bookmarkable pages or the home page) or calling a IRequestListener handler, such as Link.onClick. When that part is done, a redirect is issued to the render part, which does all the rendering of the page and its components. Be aware that this may mean, depending on whether you access any models in the action part of the request, that attachment and detachment of some models is done twice for a request.
  • ApplicationSettings.REDIRECT_TO_BUFFER. This option handles both the action- and the render part of the request in one physical request, but instead of streaming the result to the browser directly, it is kept in memory, and a redirect is issue to get this buffered result (after which it is immediately removed). This option currently is the default render strategy, as it shields you from the double submit problem, while being more efficient and less error prone regarding to detachable models.

Parameters:

renderStrategy - the render strategy that should be used by default.

Returns:

this object for chaining

setResponseRequestEncoding

public RequestCycleSettings setResponseRequestEncoding(String encoding)

In order to do proper form parameter decoding it is important that the response and the following request have the same encoding. see http://www.crazysquirrel.com/computing/general/form-encoding.jspx for additional information. Default encoding: UTF-8

Parameters:

encoding - The request and response encoding to be used.

Returns:

this object for chaining

setTimeout

public RequestCycleSettings setTimeout(Duration timeout)

Sets the time that a request will by default be waiting for the previous request to be handled before giving up.

Parameters:

timeout -

Returns:

this object for chaining

setExceptionRetryCount

public RequestCycleSettings setExceptionRetryCount(int retries)

Sets how many attempts Wicket will make to render the exception request handler before giving up.

Parameters:

retries - the number of attempts

Returns:

this object for chaining

getExceptionRetryCount

public int getExceptionRetryCount()

Returns:

How many times will Wicket attempt to render the exception request handler before giving up.