com.opensymphony.xwork2.validator.annotations

## Annotation Type ExpressionValidator

-     @Retention(value=RUNTIME)
       @Target(value=METHOD)
      public @interface ExpressionValidator

  This non-field level validator validates a supplied regular expression.

  Annotation usage:

  The annotation must be applied at method level.

  Annotation parameters:

  Parameter | Required | Default | Notes
  --- | --- | --- | ---
  message | yes |  | field error message
  key | no |  | i18n key from language specific properties file.
  messageParams | no |  | Additional params to be used to customize message - will be evaluated against the Value Stack
  shortCircuit | no | false | If this validator should be used as shortCircuit.
  expression | yes |  | An OGNL expression that returns a boolean value.

  Example code:

       @ExpressionValidator(message = "Default message", key = "i18n.key", shortCircuit = true, expression = "an OGNL expression" )

  Author:
    Rainer Hermanns

- - ### Required Element Summary

    Required Elements
    Modifier and Type | Required Element and Description
    --- | ---
    `String` | `expression`

  - ### Optional Element Summary

    Optional Elements
    Modifier and Type | Optional Element and Description
    --- | ---
    `String` | `key`
    `String` | `message`
    `String[]` | `messageParams`
    `boolean` | `shortCircuit` If this is activated, the validator will be used as short-circuit.

- - ### Element Detail

    - #### expression

          public abstract String expression

      Returns:
        The expressions to validate. An OGNL expression that returns a boolean value.

  - - #### message

          public abstract String message

      Returns:
        The default error message for this validator. NOTE: It is required to set a message, if you are not using the message key for 18n lookup!
      Default:
        ""

  - - #### key

          public abstract String key

      Returns:
        The message key to lookup for i18n.
      Default:
        ""

  - - #### messageParams

          public abstract String[] messageParams

      Returns:
        Additional params to be used to customize message - will be evaluated against the Value Stack
      Default:
        {}

  - - #### shortCircuit

          public abstract boolean shortCircuit

      If this is activated, the validator will be used as short-circuit. Adds the short-circuit="true" attribute value if `true`.
      Returns:
        true if validator will be used as short-circuit. Default is false.
      Default:
        false

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