ConditionalTagSupport

Class ConditionalTagSupport

public abstract class ConditionalTagSupport extends TagSupport

Abstract class that facilitates implementation of conditional actions where the boolean result is exposed as a JSP scoped variable. The boolean result may then be used as the test condition in a <c:when> action.

This base class provides support for:

Conditional processing of the action's body based on the returned value of the abstract method condition().
Storing the result of condition() as a Boolean object into a JSP scoped variable identified by attributes var and scope.

Author: Shawn Bayern

Constructor Summary
	ConditionalTagSupport() Base constructor to initialize local state.

Constructor Summary

ConditionalTagSupport()

Base constructor to initialize local state.

Method Summary
protected abstract boolean	condition() Subclasses implement this method to compute the boolean result of the conditional action.
int	doStartTag() Includes its body if `condition()` evaluates to true.
void	release() Releases any resources this ConditionalTagSupport may have (or inherit).
void	setScope(String scope) Sets the 'scope' attribute.
void	setVar(String var) Sets the 'var' attribute.

Method Summary

protected abstract boolean

condition()

Subclasses implement this method to compute the boolean result of the conditional action.

int

doStartTag()

Includes its body if condition() evaluates to true.

void

release()

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

void

setScope(String scope)

Sets the 'scope' attribute.

void

setVar(String var)

Sets the 'var' attribute.

Constructor Detail

ConditionalTagSupport

Base constructor to initialize local state. As with TagSupport, subclasses should not implement constructors with arguments, and no-argument constructors implemented by subclasses must call the superclass constructor.

Method Detail

condition

Subclasses implement this method to compute the boolean result of the conditional action. This method is invoked once per tag invocation by doStartTag().

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

Sets the 'var' attribute.

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