Interacting with an Iteration Action
The JSTL specification
also defines two interfaces for
iteration actions. The
javax.servlet.jsp.jstl.core.LoopTag
interface must
be implemented by iteration actions that want to cooperate with
actions nested in their bodies:
public interface LoopTag extends javax.servlet.jsp.tagext.Tag
It defines two methods nested actions can call:
public java.lang.Object getCurrent( ) public LoopTagStatus getLoopStatus( )
The
getCurrent( )
method returns the current object in the collection the action
iterates over. The
getLoopStatus( )
returns an object that implements the other JSTL iteration interface:
javax.servlet.jsp.jstl.core.LoopTagStatus
.
Before we look at the LoopTagStatus
interface,
let’s see how a
custom action can use the
LoopTag
interface. Example 23-4
shows how such a custom action can be used for the same purpose as
the custom iteration action described earlier, namely to generate an
HTML checkbox element with the checked
attribute
set depending on a dynamic list of selections.
<form action="foreachoption.jsp"> <c:forEach items="${options}"> <xmp:buildCheckbox name="choice" selections="${paramValues.choice}" /> <br> </c:forEach> <input type="submit"> </form>
Here the JSTL <c:forEach>
action loops
through a Map
with option texts and values, the
same way as in the previous example. The
<xmp:buildCheckbox>
action generates a checkbox element using the specified name ...
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