Java Doc for IRequestCycleSettings.java in  » J2EE » wicket » wicket » settings » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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 avoiding 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, 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 attachement and detachement 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.

More documentation is available about each setting in the setter method for the property.
author:
   Igor Vaynberg (ivaynberg)

This strategy is more efficient than the 'REDIRECT_TO_RENDER' strategy, and doesn't have some of the potential problems of it, it also does not solve the double submit problem. It is however the best option to use when you want to do sophisticated (non-sticky session) clustering.

This pattern solves the 'refresh' problem. While it is a common feature of browsers to refresh/ reload a web page, this results in problems in many dynamic web applications. For example, when you have a link with an event handler that e.g. deletes a row from a list, you usually want to ignore refresh requests after that link is clicked on. By using this strategy, the refresh request only results in the re-rendering of the page without executing the event handler again.

Though it solves the refresh problem, it introduces potential problems, as the request that is logically one, are actually two seperate request. Not only is this less efficient, but this also can mean that within the same request attachement/ detachement of models is done twice (in case you use models in the bookmarkable page constructors and IRequestListener handlers). If you use this strategy, you should be aware of this possibily, and should also be aware that for one logical request, actually two instances of RequestCycle are created and processed.

• 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 attachement and detachement 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.
  Note that this parameter sets the default behavior, but that you can manually set whether any redirecting is done by calling method RequestCycle.setRedirect. Setting the redirect flag when the application is configured to use ONE_PASS_RENDER, will result in a redirect of type REDIRECT_TO_RENDER. When the application is configured to use REDIRECT_TO_RENDER or REDIRECT_TO_BUFFER, setting the redirect flag to false, will result in that request begin rendered and streamed in one pass.
  Parameters:
    renderStrategy - the render strategy that should be used by default.