public ArchiveStringExpression withOperator(ArchiveStringOperator operator) {
        this.operator = operator.toString();
        return this;
    }
<p>
The operator to use when evaluating the string values.
</p>

@param operator
       The operator to use when evaluating the string values.
@return Returns a reference to this object so that method calls can be chained together.
@see ArchiveStringOperator
aws-java-sdk-mailmanager/src/main/java/com/amazonaws/services/mailmanager/model/ArchiveStringExpression.java