public abstract class ForEachSupport extends LoopTagSupport
Support for tag handlers for <forEach>, the core iteration tag in JSTL 1.0. This class extends LoopTagSupport and provides ForEach-specific functionality. The rtexprvalue library and the expression-evaluating library each have handlers that extend this class.
Localized here is the logic for handling the veritable smorgasbord of types supported by <forEach>, including arrays, Collections, and others. To see how the actual iteration is controlled, review the javax.servlet.jsp.jstl.core.LoopTagSupport class instead.
LoopTagSupport,
Serialized Form| Modifier and Type | Field and Description |
|---|---|
protected Iterator |
items |
protected Object |
rawItems |
begin, beginSpecified, deferredExpression, end, endSpecified, itemId, statusId, step, stepSpecified| Constructor and Description |
|---|
ForEachSupport() |
| Modifier and Type | Method and Description |
|---|---|
protected boolean |
hasNext()
Returns information concerning the availability of more items
over which to iterate.
|
protected Object |
next()
Returns the next object over which the tag should iterate.
|
protected void |
prepare()
Prepares for a single tag invocation.
|
void |
release()
Releases any resources this LoopTagSupport may have (or inherit).
|
doAfterBody, doCatch, doFinally, doStartTag, getCurrent, getDelims, getLoopStatus, setVar, setVarStatus, validateBegin, validateEnd, validateStepdoEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValueprotected void prepare()
throws javax.servlet.jsp.JspTagException
LoopTagSupportPrepares for a single tag invocation. Specifically, allows subclasses to prepare for calls to hasNext() and next(). Subclasses can assume that prepare() will be called once for each invocation of doStartTag() in the superclass.
prepare in class LoopTagSupportjavax.servlet.jsp.JspTagExceptionprotected boolean hasNext()
throws javax.servlet.jsp.JspTagException
LoopTagSupportReturns information concerning the availability of more items over which to iterate. This method must be provided by concrete subclasses of LoopTagSupport to assist the iterative logic provided by the supporting base class.
See next for more information about the purpose and expectations behind this tag.
hasNext in class LoopTagSupportjavax.servlet.jsp.JspTagExceptionLoopTagSupport.next()protected Object next() throws javax.servlet.jsp.JspTagException
LoopTagSupportReturns the next object over which the tag should iterate. This method must be provided by concrete subclasses of LoopTagSupport to inform the base logic about what objects it should iterate over.
It is expected that this method will generally be backed by an Iterator, but this will not always be the case. In particular, if retrieving the next object raises the possibility of an exception being thrown, this method allows that exception to propagate back to the JSP container as a JspTagException; a standalone Iterator would not be able to do this. (This explains why LoopTagSupport does not simply call for an Iterator from its subtags.)
next in class LoopTagSupportjavax.servlet.jsp.JspTagException - for other, unexpected exceptionspublic void release()
LoopTagSupportrelease in interface javax.servlet.jsp.tagext.Tagrelease in class LoopTagSupportCopyright © 2001-2014 The Apache Software Foundation. All Rights Reserved.