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:
condition().condition() as a Boolean object into a JSP scoped variable identified by
attributes var and scope.
id, pageContextEVAL_BODY_AGAINEVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE| Constructor and Description |
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ConditionalTagSupport()
Base constructor to initialize local state.
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| Modifier and Type | Method and Description |
|---|---|
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(java.lang.String scope)
Sets the 'scope' attribute.
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void |
setVar(java.lang.String var)
Sets the 'var' attribute.
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doAfterBody, doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValuepublic ConditionalTagSupport()
TagSupport, subclasses should not implement constructors
with arguments, and no-argument constructors implemented by subclasses must call the superclass constructor.protected abstract boolean condition()
throws JspTagException
Subclasses implement this method to compute the boolean result of the conditional action. This method is invoked once
per tag invocation by doStartTag().
JspTagException - on failurepublic int doStartTag()
throws JspException
condition() evaluates to true.doStartTag in interface TagdoStartTag in class TagSupportJspException - if an error occurs while processing this tagTag.doStartTag()public void release()
release in interface Tagrelease in class TagSupportTag.release()public void setVar(java.lang.String var)
var - Name of the exported scoped variable storing the result of condition().public void setScope(java.lang.String scope)
scope - Scope of the 'var' attribute