Package org.apache.taglibs.standard.util
Class ExpressionUtil
- java.lang.Object
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- org.apache.taglibs.standard.util.ExpressionUtil
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public class ExpressionUtil extends Object
Helper functions for working with EL expressions.
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Constructor Summary
Constructors Constructor Description ExpressionUtil()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static javax.el.ValueExpression
createValueExpression(javax.servlet.jsp.PageContext pageContext, String expression, Class<?> expectedType)
Create a value expression.static <T> T
evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext)
Evaluate a value expression.static boolean
evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext, boolean fallback)
static int
evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext, int fallback)
static javax.el.ExpressionFactory
getExpressionFactory(javax.servlet.jsp.PageContext pageContext)
Return the JSP's ExpressionFactory.
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Method Detail
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createValueExpression
public static javax.el.ValueExpression createValueExpression(javax.servlet.jsp.PageContext pageContext, String expression, Class<?> expectedType)
Create a value expression.- Parameters:
pageContext
- the context in which the expression will be parsedexpression
- the expressionexpectedType
- the expected type of result- Returns:
- a parsed expression
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getExpressionFactory
public static javax.el.ExpressionFactory getExpressionFactory(javax.servlet.jsp.PageContext pageContext)
Return the JSP's ExpressionFactory.- Parameters:
pageContext
- the context for the JSP- Returns:
- the ExpressionFactory to use for EL expressions in that JSP
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evaluate
public static <T> T evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext)
Evaluate a value expression. To support optional attributes, if the expression is null then null will be returned.- Type Parameters:
T
- the expected type of the expression- Parameters:
expression
- the expressionpageContext
- the context for the JSP- Returns:
- the result of evaluating the expression
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evaluate
public static boolean evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext, boolean fallback)
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evaluate
public static int evaluate(javax.el.ValueExpression expression, javax.servlet.jsp.PageContext pageContext, int fallback)
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