com.opensymphony.xwork2.validator.validators

## Class RequiredStringValidator

- java.lang.Object
- - com.opensymphony.xwork2.validator.validators.ValidatorSupport
  - - com.opensymphony.xwork2.validator.validators.FieldValidatorSupport
    - - com.opensymphony.xwork2.validator.validators.RequiredStringValidator

- All Implemented Interfaces:
    FieldValidator, ShortCircuitableValidator, Validator

      public class RequiredStringValidator
      extends FieldValidatorSupport

  RequiredStringValidator checks that a String field is non-null and has a length > 0. (i.e. it isn't ""). The "trim" parameter determines whether it will `trim` the String before performing the length check. If unspecified, the String will be trimmed.
  - fieldName - The field name this validator is validating. Required if using Plain-Validator Syntax otherwise not required
  - trim - (Optional) Boolean, default true. Trims the field name value before validating.
  - trimExpression - (Optional) String. Specifies the trim param as an OGNL expression.
  Do not use ${trimExpression} as an expression as this will turn into infinitive loop!

           <validators>
               <!-- Plain-Validator Syntax -->
               <validator type="requiredstring">
                   <param name="fieldName">username</param>
                   <param name="trim">true</param>
                   <message>username is required</message>
               </validator>

               <!-- Field-Validator Syntax -->
               <field name="username">
                        <field-validator type="requiredstring">
                       <param name="trim">true</param>
                       <message>username is required</message>
                  </field-validator>
               </field>

               <!-- Field-Validator Syntax with expression -->
               <field name="username">
                        <field-validator type="requiredstring">
                       <param name="trimExpression">${trimValue}</param> <!-- will be evaluated as: boolean getTrimValue() -->
                       <message>username is required</message>
                  </field-validator>
               </field>
           </validators>

  Author:
    rainerh

- - ### Field Summary

    - ### Fields inherited from class com.opensymphony.xwork2.validator.validators.FieldValidatorSupport

      `currentValue, fieldName, type`

    - ### Fields inherited from class com.opensymphony.xwork2.validator.validators.ValidatorSupport

      `defaultMessage, EMPTY_STRING, messageKey, stack, textProviderFactory`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `RequiredStringValidator()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `isTrim()`
    `void` | `setTrim(boolean trim)`
    `void` | `setTrimExpression(String trimExpression)`
    `void` | `validate(Object object)` The validation implementation must guarantee that setValidatorContext will be called with a non-null ValidatorContext before validate is called.
    `protected void` | `validateValue(Object object, Object fieldValue)`

    - ### Methods inherited from class com.opensymphony.xwork2.validator.validators.FieldValidatorSupport

      `getCurrentValue, getFieldName, getValidatorType, setFieldName, setValidatorType`

    - ### Methods inherited from class com.opensymphony.xwork2.validator.validators.ValidatorSupport

      `addActionError, addFieldError, getDefaultMessage, getFieldValue, getMessage, getMessageKey, getMessageParameters, getValidatorContext, isShortCircuit, parse, setDefaultMessage, setMessageKey, setMessageParameters, setShortCircuit, setTextProviderFactory, setValidatorContext, setValueStack`

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

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

    - ### Methods inherited from interface com.opensymphony.xwork2.validator.Validator

      `getDefaultMessage, getMessage, getMessageKey, getMessageParameters, getValidatorContext, setDefaultMessage, setMessageKey, setMessageParameters, setValidatorContext, setValueStack`

- - ### Constructor Detail

    - #### RequiredStringValidator

          public RequiredStringValidator()

  - ### Method Detail

    - #### setTrim

          public void setTrim(boolean trim)

    - #### setTrimExpression

          public void setTrimExpression(String trimExpression)

    - #### isTrim

          public boolean isTrim()

    - #### validate

          public void validate(Object object)
                        throws ValidationException

      Description copied from interface: `Validator`
      The validation implementation must guarantee that setValidatorContext will be called with a non-null ValidatorContext before validate is called.
      Parameters:
        `object` - the object to be validated.
      Throws:
        `ValidationException` - is thrown if there is validation error(s).

    - #### validateValue

          protected void validateValue(Object object,
                                       Object fieldValue)

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