Interface RequestInterceptor
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public interface RequestInterceptor
Used to intercept the requests for the ZK Loader and Update Engine. Developers usually use it to prepare the locale and time zone.request(org.zkoss.zk.ui.Session, java.lang.Object, java.lang.Object)
is called at very early stage, even before setting the locale for the request. Thus, you can configure the locale as follows:
sess.setAttribute(
Attributes.PREFERRED_LOCALE
, myLocale);By default, the locale is decided by the browser's preference. However, you may want to store the previous locale in the cookie if your application is HTTP. Another example, you may want to retrieve the locale from the database where your application stores user's preferences.
Similarly, you can configure the time zone (that is used by some components, such as Datebox) as follows:
sess.setAttribute(
Attributes.PREFERRED_TIME_ZONE
, myLocale);How this interface is used.
- First, you specify a class that implements this interface in WEB-INF/zk.xml as a listener. Then, an instance of the specified class is created.
- Each time ZK Loader or ZK Update Engine receives a request,
it first invoke
request(org.zkoss.zk.ui.Session, java.lang.Object, java.lang.Object)
against the instance created in the previous step.
Note:
- Unlike
ExecutionInit
and others listeners, the same instance ofRequestInterceptor
is used for the whole application. Thus, you have to make sure it can be accessed concurrently.
Differences to
URIInterceptor
URIInterceptor
is called when retrieving a page definition from an URI (PageDefinitions.getPageDefinition(org.zkoss.zk.ui.WebApp, org.zkoss.util.resource.Locator, java.lang.String)
). It may or may not be caused by a client request. On the other hand,RequestInterceptor
is called when ZK Loader or ZK Update Engine is receiving a client request.- Author:
- tomyeh
- See Also:
URIInterceptor
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
request(Session sess, java.lang.Object request, java.lang.Object response)
Called before a request is processed by ZK Loader or ZK Update Engine.
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Method Detail
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request
void request(Session sess, java.lang.Object request, java.lang.Object response)
Called before a request is processed by ZK Loader or ZK Update Engine.- Parameters:
sess
- the session (never null)request
- the request (never null). It is javax.servlet.http.HttpServletRequest, if the application is HTTP based. A common use is to look for the cookies.response
- the response (never null). It is javax.servlet.http.HttpServletResponse, if the application is HTTP based. A common use is to store the cookies.
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