A validator is a class that implements the validate() method of the atg.cim.worker.IValidator. To write your own validator object, you will need to provide the concrete implementation of the methods defined in the IValidator class.

public interface IValidator {

  /**
   * Called by the CIM Framework before calling validate().
   *
   * @return true if the object can validate values
   */
  public boolean canValidate();

  /**
   * Logic to test a condition should be placed in this method.  Code should
   * update the message property so the framework may retrieve the last state of
   * the component.
   *
   * @throws ValidatorException
   */
  public boolean validate() throws ValidatorException;

  /**
   * Returns a brief message describing the state of the object.
   *
   */
  public String getMessage();

}

It is a good practice to end your class name with Validator (such as ATGLicenseValidator) and include it under the package atg.cim.validator.