public String getPrincipalId() {
        return this.principalId;
    }
<p>
A unique identifier for the entity that made the call. For Time To Live, the principalId is
"dynamodb.amazonaws.com".
</p>

@return A unique identifier for the entity that made the call. For Time To Live, the principalId is
        "dynamodb.amazonaws.com".
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/model/Identity.java