Package org.zkoss.web.servlet.xel

Class RequestContexts

  • public class RequestContexts
extends java.lang.Object
    RequestContexts maintains a stack of RequestContext to simplify the signatures of the XEL function.

    It is designed to make the signature of XEL functions (see ServletFns) simpler. For example, ServletFns.getCurrentContext() requires no argument, since it assumes the current context can be retrieved from getCurrent().

    Spec Issue:
    It is controversial whether the introduction of RequestContext and RequestContexts is worth. However, we have to maintain the backward compatibility of the XEL/EL function signatures.

    Since:
    3.0.0
    Author:
    tomyeh

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected RequestContexts()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static RequestContext getCurrent()
      Returns the current page context if this thread is evaluating a page, or null if not.
      static void pop()
      Pops the context out and use the previous one as the current context.
      static void push​(RequestContext jc)
      Pushes the context as the current context, such that it will be returned by getCurrent().

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • RequestContexts

        protected RequestContexts()

    • Method Detail

      • getCurrent

        public static final RequestContext getCurrent()
        Returns the current page context if this thread is evaluating a page, or null if not.

      • push

        public static final void push​(RequestContext jc)
        Pushes the context as the current context, such that it will be returned by getCurrent(). The reason this method exists is many functions (ServletFns) counts on it.

        However, you don't need to invoke this method if you are using DSP.

        1. If go thru DSP, it is done automatically (by Interpreter

        Note: you must use try/finally as follows: 

        RequestContexts.push(jc);
try {
  ...
} finally {
  RequestContexts.pop();
}

      • pop

        public static final void pop()
        Pops the context out and use the previous one as the current context.

        However, you don't need to invoke this method if you are using DSP.

        See Also:
        push(org.zkoss.web.servlet.xel.RequestContext)