Heartbeat Aggregate Sample

The HeartbeatAggregate.sbapp sample uses a Heartbeat operator to output the number of stock quotes received every five seconds. The actual counting is done by an Aggregate operator, but it depends on the Heartbeat to trigger output during periods when no quotes are received.

Running HeartbeatAggregate.sbapp in StreamBase Studio

  1. In the Package Explorer, double-click to open the HeartbeatAggregate.sbapp application. Make sure the application is the currently active tab in the EventFlow Editor.

  2. Click the Run button. This opens the SB Test/Debug perspective and starts the application.

  3. In the Application Output view, select the TicCounts stream. No output is displayed at this point, but the Output View is prepared to receive output. This view will eventually show the output of the application.

  4. In the Manual Input view, select the InputTics input stream

  5. Enter IBM for symbol, and 83.17 for price.

  6. Click Send Data. Within five seconds, look for a tuple on the TicCounts output stream, stating that one quote was received in the last five seconds.

  7. Click Send Data three times in rapid succession. Within five seconds, look for a tuple on the TicCounts output stream, stating that three quotes were received in the last five seconds.

  8. Wait five seconds and look for a tuple on the TicCounts output stream, stating that zero quotes were received in the last five seconds.

  9. When done, press F9 or click the Stop Running Application button.

Running HeartbeatAggregate.sbapp in Terminal Windows

This section describes how to run the sample in UNIX terminal windows or Windows command prompt windows. On Windows, be sure to use the StreamBase Command Prompt from the Start menu as described in the Test/Debug Guide, not the default command prompt.

  1. Open three terminal windows on UNIX, or three StreamBase Command Prompts on Windows. In each window, navigate to the directory where the sample is installed, or to your workspace copy of the sample, as described above.

  2. In window 1, type:

    sbd HeartbeatAggregate.sbapp

    The window shows notice[StreamBaseServer] listening on port 10000.

  3. In window 2, type:

    sbc dequeue TicCounts

    No output is displayed at this point, but the dequeuer is prepared to receive output of the application.

  4. In window 3, type:

    echo IBM,84.17 | sbc enqueue SetPrice

    Within five seconds, look for a tuple in the dequeue window stating that one quote was received in the last five seconds.

  5. Wait five seconds and look for another tuple in the dequeue window stating that zero quotes were received in the last five seconds.

  6. In window 2, type: Ctrl+Z (Windows) or Ctrl+D (UNIX) to exit the sbc session.

  7. In window 3, type the following command to terminate the server and dequeuer:

    sbadmin shutdown

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Importing This Sample into StreamBase Studio

In StreamBase Studio, import this sample with the following steps:

  • From the top menu, click FileLoad StreamBase Sample.

  • Select operator from the Data Constructs and Operators category.

  • Click OK.

StreamBase Studio creates a single project for the operator samples.

Sample Location

When you load the sample into StreamBase Studio, Studio copies the sample project's files to your Studio workspace, which is normally part of your home directory, with full access rights.

Important

Load this sample in StreamBase Studio, and thereafter use the Studio workspace copy of the sample to run and test it, even when running from the command prompt.

Using the workspace copy of the sample avoids permission problems. The default workspace location for this sample is:

studio-workspace/sample_operator

See Default Installation Directories for the location of studio-workspace on your system.

In the default TIBCO StreamBase installation, this sample's files are initially installed in:

streambase-install-dir/sample/operator

See Default Installation Directories for the default location of studio-workspace on your system.