Package javax.servlet.jsp.jstl.core
Class ConditionalTagSupport
- java.lang.Object
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- javax.servlet.jsp.tagext.TagSupport
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- javax.servlet.jsp.jstl.core.ConditionalTagSupport
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- All Implemented Interfaces:
IterationTag
,JspTag
,Tag
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.
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from interface javax.servlet.jsp.tagext.IterationTag
EVAL_BODY_AGAIN
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Fields inherited from interface javax.servlet.jsp.tagext.Tag
EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE
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Fields inherited from class javax.servlet.jsp.tagext.TagSupport
id, pageContext
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Constructor Summary
Constructors Constructor Description ConditionalTagSupport()
Base constructor to initialize local state.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method 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.void
setVar(java.lang.String var)
Sets the 'var' attribute.-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from class javax.servlet.jsp.tagext.TagSupport
doAfterBody, doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue
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Method Detail
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condition
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().
- Returns:
- a boolean representing the condition that a particular subclass uses to drive its conditional logic.
- Throws:
JspTagException
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doStartTag
public int doStartTag() throws JspException
Includes its body if condition() evaluates to true.- Specified by:
doStartTag
in interfaceTag
- Overrides:
doStartTag
in classTagSupport
- Returns:
- SKIP_BODY
- Throws:
JspException
- if an error occurs while processing this tag- See Also:
Tag.doStartTag()
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release
public void release()
Releases any resources this ConditionalTagSupport may have (or inherit).- Specified by:
release
in interfaceTag
- Overrides:
release
in classTagSupport
- See Also:
Tag.release()
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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().
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setScope
public void setScope(java.lang.String scope)
Sets the 'scope' attribute.- Parameters:
scope
- Scope of the 'var' attribute
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