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Create Feed

The Create Feed example creates a Feed, which it subscribes to the partition containing our ToDoItems.

A Feed is a queue, which provides at least once delivery of objects which are created or updated in the Object Store. A Feed can be subscribed to one or more Partitions, which means that whenever an object is created which is a member of one of those Partitions, the new object will be placed onto the Feed to be read.

The first part of the program is almost identical to the Hello World Example, see the description there for more details.

In this case we also need to provide the Object Store URL, since these examples use that API.

public class CreateFeed extends CommandLineHandler implements Runnable
{
  private static final Logger log_ = LoggerFactory.getLogger(CreateFeed.class);
  
  private static final String ALLEGRO          = "ALLEGRO_";
  private static final String SERVICE_ACCOUNT  = "SERVICE_ACCOUNT";
  private static final String POD_URL          = "POD_URL";
  private static final String OBJECT_STORE_URL = "OBJECT_STORE_URL";
  private static final String CREDENTIAL_FILE  = "CREDENTIAL_FILE";
  private static final String OWNER_USER_ID    = "OWNER_USER_ID";
  private static final String OTHER_USER_ID    = "OTHER_USER_ID";
  
  private String              serviceAccount_;
  private String              podUrl_;
  private String              objectStoreUrl_;
  private String              credentialFile_;
  private PodAndUserId        ownerId_;
  private PodAndUserId        otherUserId_;
  
  private IAllegroApi         allegroApi_;

  /**
   * Constructor.
   */
  public CreateFeed()
  {
    withFlag('s',   SERVICE_ACCOUNT,  ALLEGRO + SERVICE_ACCOUNT,  String.class,   false, true,   (v) -> serviceAccount_       = v);
    withFlag('p',   POD_URL,          ALLEGRO + POD_URL,          String.class,   false, true,   (v) -> podUrl_               = v);
    withFlag('o',   OBJECT_STORE_URL, ALLEGRO + OBJECT_STORE_URL, String.class,   false, true,   (v) -> objectStoreUrl_       = v);
    withFlag('f',   CREDENTIAL_FILE,  ALLEGRO + CREDENTIAL_FILE,  String.class,   false, true,   (v) -> credentialFile_       = v);
    withFlag('u',   OWNER_USER_ID,    ALLEGRO + OWNER_USER_ID,    Long.class,     false, false,  (v) -> ownerId_              = PodAndUserId.newBuilder().build(v));
    withFlag(null,  OTHER_USER_ID,    ALLEGRO + OTHER_USER_ID,    Long.class,     false, false,  (v) -> otherUserId_          = PodAndUserId.newBuilder().build(v));
  }
  
  @Override
  public void run()
  {
    allegroApi_ = new AllegroApi.Builder()
      .withPodUrl(podUrl_)
      .withObjectStoreUrl(objectStoreUrl_)
      .withUserName(serviceAccount_)
      .withRsaPemCredentialFile(credentialFile_)
      .withFactories(CalendarModel.FACTORIES)
      .withTrustAllSslCerts()
      .build();
    
    System.out.println("CallerId is " + allegroApi_.getUserId());
    System.out.println("OwnerId is " + otherUserId_);
    System.out.println("OtherUserId is " + otherUserId_);

In the next part of the program we create a ResourcePermissions object if the optional OTHER_USER_ID parameter is provided to grant that user read access to the feed:

    ResourcePermissions permissions = null;
    
    if(otherUserId_ != null)
    {
      permissions = new ResourcePermissions.Builder()
          .withUser(otherUserId_, Permission.Read)
          .build()
          ;
    }

Next we call the upsertFeed method to create the feed and its subscription to the Partition. As this is an upsert operation:

    UpsertFeedRequest.Builder builder = new UpsertFeedRequest.Builder()
        .withName("myCalendarFeed")
        .withPermissions(permissions)
        .withPartitionIds(
            new PartitionId.Builder()
            .withName(CalendarApp.PARTITION_NAME)
            .withOwner(ownerId_)
            .build()
            )
        ;
    
    IFeed feed = allegroApi_.upsertFeed(builder.build());
    
    log_.info("Feed is " + feed);

When we run the program the first thing we see is some preliminary log messages:

2020-06-09T10:55:38.085000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - AllegroApi constructor start
2020-06-09T10:55:38.305000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - sbe auth....
2020-06-09T10:55:39.029000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - fetch podInfo_....
2020-06-09T10:55:39.150000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - keymanager auth....
2020-06-09T10:55:39.313000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - getAccountInfo....
2020-06-09T10:55:39.622000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - userId_ = 351775001412007
2020-06-09T10:55:39.626000000Z [main               ] INFO  com.symphony.oss.allegro.api.AllegroApi - allegroApi constructor done.
CallerId is 351775001412007
OwnerId is null
OtherUserId is null

Then we see the feed meta data:

``` 2020-06-09T10:55:40.540000000Z [main ] INFO com.symphony.s2.allegro.examples.calendar.CreateFeed - Feed is { “_type”:”com.symphony.s2.model.object.Feed”, “_version”:”1.0”, “hashType”:1, “id”:{ “_type”:”com.symphony.s2.model.object.NamedUserIdObject”, “_version”:”1.0”, “hashType”:1, “name”:”myCalendarFeed”, “userId”:351775001412007 }, “queueName”:”sym-s2-dev-s2smoke2-object-feed-cMUuB1d1Px8pmrIc8EB7ZX” }