Package org.apache.taglibs.standard.util

Class ExpressionUtil

  • public class ExpressionUtil
extends Object
    Helper functions for working with EL expressions.

    • Constructor Summary

      Constructors 
      Constructor Description
      ExpressionUtil()  

    • 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.

    • 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)