org.zkoss.web.servlet.xel

Class RequestContexts

java.lang.Object

org.zkoss.web.servlet.xel.RequestContexts

public class RequestContexts
extends 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.isExplorer() 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 and Description
protected	RequestContexts()

Method Summary

Methods

Modifier and Type	Method and 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)