javax.servlet.jsp.jstl.core
Class ConditionalTagSupport

java.lang.Object
  |
  +--javax.servlet.jsp.tagext.TagSupport
        |
        +--javax.servlet.jsp.jstl.core.ConditionalTagSupport

All Implemented Interfaces:

IterationTag, java.io.Serializable, Tag

public abstract class ConditionalTagSupport

extends TagSupport

ConditionalTagSupport is an abstract class that facilitates implementation of conditional tags -- specifically, tags in the style of <if>.

In particular, this base class provides support for:

• conditional execution based on an overridable condition() method
• scoped attributes storing the result (as a Boolean) of the logic executed by a subclass (optionally by attribute)

Since this method implements the behavior anticipated to be recommended by the standard (with respect to tags that support boolean logic), it is expected that it will be part of the JSTL API.

See Also:

Serialized Form

Fields inherited from class javax.servlet.jsp.tagext.TagSupport

id, pageContext

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag

EVAL_BODY_AGAIN

Fields inherited from interface javax.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

ConditionalTagSupport()
Base constructor to initialize local state.

Method Summary

protected abstract boolean	condition() Returns a boolean representing the condition that a particular subclass uses to drive its conditional logic.
int	doStartTag() Includes its body if condition() evalutes to true.
void	release() Releases any resources this ConditionalTagSupport may have (or inherit).
void	setScope(java.lang.String scope) Sets the 'scope' attribute.
void	setVar(java.lang.String var) Sets the 'var' attribute.

Methods inherited from class javax.servlet.jsp.tagext.TagSupport

doAfterBody, doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue

Methods inherited from class java.lang.Object

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

Constructor Detail

ConditionalTagSupport

public ConditionalTagSupport()

Base constructor to initialize local state. As with TagSupport, subclasses should not provide other constructors and are expected to call the superclass constructor.

Method Detail

condition

protected abstract boolean condition()
                              throws JspTagException

Returns a boolean representing the condition that a particular subclass uses to drive its conditional logic.

Returns:

a boolean representing the result of arbitrary logic that will be used to drive a tag's behavior

doStartTag

public int doStartTag()
               throws JspException

Includes its body if condition() evalutes to true.

Overrides:

doStartTag in class TagSupport

Following copied from class: javax.servlet.jsp.tagext.TagSupport

See Also:

Tag.doStartTag()

release

public void release()

Releases any resources this ConditionalTagSupport may have (or inherit).

Overrides:

release in class TagSupport

Following copied from class: javax.servlet.jsp.tagext.TagSupport

See Also:

Tag.release()

setVar

public void setVar(java.lang.String var)

Sets the 'var' attribute.

Parameters:

var - Name of the exported scoped variable storing the result of condition().

setScope

public void setScope(java.lang.String scope)

Sets the 'scope' attribute.

Parameters:

scope - Scope of the 'var' attribute