public void saveIfNotExists(T object) throws ConditionalCheckFailedException {
        final DynamoDBSaveExpression saveExpression = new DynamoDBSaveExpression();
        for (final DynamoDBMapperFieldModel<T,Object> key : model.keys()) {
            saveExpression.withExpectedEntry(key.name(), new ExpectedAttributeValue()
                .withExists(false));
        }
        mapper.<T>save(object, saveExpression);
    }
Saves the object given into DynamoDB with the condition that the hash
and if applicable, the range key, does not already exist.
@param object The object to create.
@throws ConditionalCheckFailedException If the object exists.
@see com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper#save
@see com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBSaveExpression
@see com.amazonaws.services.dynamodbv2.model.ExpectedAttributeValue
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/datamodeling/DynamoDBTableMapper.java