saqua

Simple Android Queue ( Useful for Async )

What is it

This is Android/Java library with simple Queue interface and it persistent implementation used build in Android SQLite. It help perform async exchange with remote servers in case of unstable network connection.

Naming

Originally saqua - a fancy alcohol drink from Endmond Hamilton's cosmic opera "The Star Kings". "A cursed good drink!" as main person say about it. So, why not.

Example usage

Initializing

public class App extends Application {
  ...
  // Init DB Queue factory, must be performed before obtained first queue  
  SimpleDBQueueFactory.initFactory(getApplicationContext());
  ...
}

Produce messages

public void storeDocument(Document docToStore) {
    SimpleDBQueue backupQueue = SimpleDBQueueFactory.getQueue("backup_documents");
    backupQueue.push(docToStore, ImmutableMap.of("collection", backupCollection));
    SimpleDBQueue docsQueue = SimpleDBQueueFactory.getQueue("documents");
    docsQueue.push(docToStore);    
}

Consume messages

public class BackupDocumentsService extends AsyncTask {
  @Override
  protected Object doInBackground(Object[] params) {
    SimpleDBQueue queue = SimpleDBQueueFactory.getQueue("backup_documents");
    while (!queue.isEmpty()) {
      SimpleQueueMessage message = queue.pull();
      String backupCollection = message.getHeaders().get("backup_collection");
      if (backupCollection == null) {
        queue.Ack(); // wrong record, skip
      } else {
        objectToStore = message.getBody();
        if (RemoteService.storeBackupObject(backupCollection, objectToStore)) {
          queue.Ack();
        } else {
          queue.NAck();
        }
      }
    }
    return null;
  }
}