Expression (JSP 2.3 API Documentation - Apache Tomcat 8.5.43)

javax.servlet.jsp.el

## Class Expression

- java.lang.Object
- - javax.servlet.jsp.el.Expression

- Deprecated.
  As of JSP 2.1, replaced by javax.el.ValueExpression

      public abstract class Expression
      extends java.lang.Object

  The abstract class for a prepared expression.

  An instance of an Expression can be obtained via from an ExpressionEvaluator instance.

  An Expression may or not have done a syntactic parse of the expression. A client invoking the evaluate() method should be ready for the case where ELParseException exceptions are raised.

  Since:
    2.0

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `Expression()` Deprecated.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `abstract java.lang.Object` | `evaluate(VariableResolver vResolver)` Deprecated. Evaluates an expression that was previously prepared.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### Expression

          public Expression()

      Deprecated.

  - ### Method Detail

    - #### evaluate

          public abstract java.lang.Object evaluate(VariableResolver vResolver)
                                             throws ELException

      Deprecated.
      Evaluates an expression that was previously prepared. In some implementations preparing an expression involves full syntactic validation, but others may not do so. Evaluating the expression may raise an ELParseException as well as other ELExceptions due to run-time evaluation.
      Parameters:
        `vResolver` - A VariableResolver instance that can be used at runtime to resolve the name of implicit objects into Objects.
      Returns:
        The result of the expression evaluation.
      Throws:
        `ELException` - Thrown if the expression evaluation failed.

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