CODEWITHSUNDEEP
google-cloud-datastore
Marco Tedone
Marco Tedone

Reputation: 602

Google Cloud Datastore (not Appengine): How to set a Java collection in an Entity

I'm using a non AppEngine Google Cloud Datastore Java API. I store entities from outside the Google Cloud environment.

My Gradle dependency is:

compile('com.google.cloud:google-cloud-datastore:0.8.0-beta')

I have a List in an entity that I'd like to set in the Entity but there is no method to set a collection. Currently I'm setting values as follows: 

/**
 * It returns a Google Datastore Entity from a DTO Entity
 * @param usersKey The Key to use to build the entity
 * @param user The Users entity containing the data to persist
 * @return A Google Datastore Entity from a DTO Entity
 */
public static Entity fromDtoToGoogleEntity(Key usersKey, User user) {

    Entity.Builder builder = Entity.newBuilder(usersKey);
    builder.set(User.FIRST_NAME, user.getFirstName());
    builder.set(User.LAST_NAME, user.getLastName());
    builder.set(User.PASSWORD, user.getPassword());
    builder.set(User.EMAIL, user.getEmail());
    builder.set(User.STRIPE_USER_ID, user.getStripeUserId());
    builder.set(User.COUNTRY, user.getCountry());
    builder.set(User.DESCRIPTION, user.getDescription());
    builder.set(User.USERNAME, user.getUsername());
    builder.set(User.ENABLED, user.isEnabled());       

    return builder.build();

}

There is no method such as: 

builder.set(User.USER_ROLES, user.getUserRoles());//userRoles is a List<String>

Can anybody suggest a way? The only way so far is to have a comma separated String representation and convert from Collection to comma separated String and vice versa.

Thanks in advance.

M.

Upvotes: 0

Views: 350

Answers (1)

Sai Pullabhotla
Sai Pullabhotla

Reputation: 2207

You can use either of the below methods (http://googlecloudplatform.github.io/google-cloud-java/0.8.0/apidocs/com/google/cloud/datastore/BaseEntity.Builder.html) - 

set(String name, List<? extends Value<?>> values)
set(String name, String first, String second, String... others)

See also the ListValue and ListValue.Builder.

The first one - you just create a list of Value objects (e.g. StringValue) and assign the list to a property on the entity. In essence, convert your List<String> to List<StringValue>.

The second one is a simpler variation with String var args, where you can pass your two or more Strings.

You may also consider using an ORM framework like Catatumbo (http://catatumbo.io) which takes care of the mapping of your model objects.

Disclosure: I'm the author of Catatumbo.

Upvotes: 1

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