## org.springframework.web.util
Class ExpressionEvaluationUtils

    java.lang.Object
      org.springframework.web.util.ExpressionEvaluationUtils

    public abstract class ExpressionEvaluationUtils

extends Object

Convenience methods for accessing JSP 2.0's `ExpressionEvaluator`.

The evaluation methods check if the value contains "${" before invoking the EL evaluator, treating the value as "normal" expression (i.e. a literal String value) else.

Since:
  11.07.2003
Author:
  Juergen Hoeller, Alef Arendsen
See Also:
  `ExpressionEvaluator.evaluate(java.lang.String, java.lang.Class, javax.servlet.jsp.el.VariableResolver, javax.servlet.jsp.el.FunctionMapper)`

Field Summary
`static String` `EXPRESSION_PREFIX`
`static String` `EXPRESSION_SUFFIX`

Constructor Summary
`ExpressionEvaluationUtils()`

Method Summary
`static Object` `evaluate(String attrName, String attrValue, Class resultClass, PageContext pageContext)` Evaluate the given expression (be it EL or a literal String value) to an Object of a given type,
`static Object` `evaluate(String attrName, String attrValue, PageContext pageContext)` Evaluate the given expression (be it EL or a literal String value) to an Object.
`static boolean` `evaluateBoolean(String attrName, String attrValue, PageContext pageContext)` Evaluate the given expression (be it EL or a literal String value) to a boolean.
`static int` `evaluateInteger(String attrName, String attrValue, PageContext pageContext)` Evaluate the given expression (be it EL or a literal String value) to an integer.
`static String` `evaluateString(String attrName, String attrValue, PageContext pageContext)` Evaluate the given expression (be it EL or a literal String value) to a String.
`static boolean` `isExpressionLanguage(String value)` Check if the given expression value is an EL expression.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### EXPRESSION_PREFIX

    public static final String EXPRESSION_PREFIX

See Also:
  Constant Field Values

### EXPRESSION_SUFFIX

    public static final String EXPRESSION_SUFFIX

See Also:
  Constant Field Values

Constructor Detail

### ExpressionEvaluationUtils

    public ExpressionEvaluationUtils()

Method Detail

### isExpressionLanguage

    public static boolean isExpressionLanguage(String value)

  Check if the given expression value is an EL expression.

  Parameters:
    `value` - the expression to check
  Returns:
    `true` if the expression is an EL expression, `false` otherwise

### evaluate

    public static Object evaluate(String attrName,
                                  String attrValue,
                                  Class resultClass,
                                  PageContext pageContext)
                           throws JspException

  Evaluate the given expression (be it EL or a literal String value) to an Object of a given type,

  Parameters:
    `attrName` - name of the attribute (typically a JSP tag attribute)
    `attrValue` - value of the attribute
    `resultClass` - class that the result should have (String, Integer, Boolean)
    `pageContext` - current JSP PageContext
  Returns:
    the result of the evaluation
  Throws:
    `JspException` - in case of parsing errors, also in case of type mismatch if the passed-in literal value is not an EL expression and not assignable to the result class

### evaluate

    public static Object evaluate(String attrName,
                                  String attrValue,
                                  PageContext pageContext)
                           throws JspException

  Evaluate the given expression (be it EL or a literal String value) to an Object.

  Parameters:
    `attrName` - name of the attribute (typically a JSP tag attribute)
    `attrValue` - value of the attribute
    `pageContext` - current JSP PageContext
  Returns:
    the result of the evaluation
  Throws:
    `JspException` - in case of parsing errors

### evaluateString

    public static String evaluateString(String attrName,
                                        String attrValue,
                                        PageContext pageContext)
                                 throws JspException

  Evaluate the given expression (be it EL or a literal String value) to a String.

  Parameters:
    `attrName` - name of the attribute (typically a JSP tag attribute)
    `attrValue` - value of the attribute
    `pageContext` - current JSP PageContext
  Returns:
    the result of the evaluation
  Throws:
    `JspException` - in case of parsing errors

### evaluateInteger

    public static int evaluateInteger(String attrName,
                                      String attrValue,
                                      PageContext pageContext)
                               throws JspException

  Evaluate the given expression (be it EL or a literal String value) to an integer.

  Parameters:
    `attrName` - name of the attribute (typically a JSP tag attribute)
    `attrValue` - value of the attribute
    `pageContext` - current JSP PageContext
  Returns:
    the result of the evaluation
  Throws:
    `JspException` - in case of parsing errors

### evaluateBoolean

    public static boolean evaluateBoolean(String attrName,
                                          String attrValue,
                                          PageContext pageContext)
                                   throws JspException

  Evaluate the given expression (be it EL or a literal String value) to a boolean.

  Parameters:
    `attrName` - name of the attribute (typically a JSP tag attribute)
    `attrValue` - value of the attribute
    `pageContext` - current JSP PageContext
  Returns:
    the result of the evaluation
  Throws:
    `JspException` - in case of parsing errors