Connecting to Accumulo

Accumulo Tour: Connecting to Accumulo

Tour page 2 of 13

Connecting to a live instance of Accumulo is done through the AccumuloClient object. This object contains a live connection to Accumulo and will remain open until closed. All client operations can be accessed from this one object.

The Accumulo entry point is used to create a client by calling Accumulo.newClient(). The client can be created from properties by using one of the from() methods or using the to() and as() methods to specify the connection information directly. A later example will illustrate how to create a new client.

For the tour, you will use the client provided by the JShell to perform the required operations. The properties used to create the client can be viewed in the file contained in the clientPropUrl variable.

jshell> /vars
|    URL clientPropUrl = file:< file>

Let’s start by using table operations to list the default tables and instance operations to get the instance ID.

jshell> client.tableOperations().list().forEach(System.out::println);

Now let’s retrieve the instance ID.

jshell> System.out.println(client.instanceOperations().getInstanceID());

Different types of operations are accessed by their respective methods on the client:

  • client.tableOperations();
  • client.namespaceOperations();
  • client.securityOperations();
  • client.instanceOperations();
  • client.replicationOperations();

The client is also used to create Scanners and perform batch operations. These will be explored later.

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