org.apache.taglibs.standard.util
Class ExpressionUtil

java.lang.Object
  extended by org.apache.taglibs.standard.util.ExpressionUtil

public class ExpressionUtil
extends Object

Helper functions for working with EL expressions.


Constructor Summary
ExpressionUtil()
           
 
Method Summary
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.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExpressionUtil

public ExpressionUtil()
Method Detail

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 parsed
expression - the expression
expectedType - the expected type of result
Returns:
a parsed expression

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

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 expression
pageContext - the context for the JSP
Returns:
the result of evaluating the expression

evaluate

public static boolean evaluate(javax.el.ValueExpression expression,
                               javax.servlet.jsp.PageContext pageContext,
                               boolean fallback)

evaluate

public static int evaluate(javax.el.ValueExpression expression,
                           javax.servlet.jsp.PageContext pageContext,
                           int fallback)


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