Metronome Operator Sample

About This Guide

This sample uses a Metronome operator to output the current share price of all stocks every five seconds. The current prices are stored in a query table.

Importing This Sample into StreamBase Studio

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

  • From the top menu, click FileLoad StreamBase Sample.

  • Type operator to narrow the list of options.

  • Select Operator sample group from the Data Constructs and Operators category.

  • Click OK.

StreamBase Studio creates a single project for the operator samples.

Running Metronome.sbapp in StreamBase Studio

  1. In the Project Explorer, open the sample you just loaded.

  2. Open the src/main/eventflow folder.

  3. Open the package folder (most samples contain a single package folder. Open the top-level package folder if your sample contains more than one folder).

  4. Open the Metronome.sbapp application and click the Run button. This opens the SB Test/Debug perspective and starts the application.

    If you see red marks, wait a moment for the project in Studio to load its features.

    If red marks do not resolve themselves in a moment, select the project and right-click MavenUpdate Project from the context menu.

  5. In the Application Output view, select the CurrentPrices stream. Observe a tuple showing every five seconds, with the current time, a null symbol, and a null price. This indicates that no prices are currently known. Once we record some share prices, the nulls will be replaced with actual values.

  6. In the Manual Input view, enter INTC for symbol, and 23.25 for price.

  7. Click Send Data. Within five seconds, look for a tuple on the CurrentPrices output stream, stating that the current price of INTC is 23.25.

  8. Enter MSFT for symbol, and 25.75 for price.

  9. Click Send Data. Within five seconds, look for two tuples emitted on the CurrentPrices output stream. These tuples are repeated every five seconds.

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

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 default location of studio-workspace on your system.