public Item withKeyComponents(KeyAttribute ...components) {
        rejectNullOrEmptyInput(components);
        for (KeyAttribute ka: components) {
            rejectNullValue(ka);
            this.with(ka.getName(), ka.getValue());
        }
        return this;
    }
Convenient methods - sets the attributes of this item from the specified
key components.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/document/Item.java