Union Operator Sample

About This Sample

The Union operator sample uses a Union operator to interleave trades from a Reuters feed and the Interactive Data PlusFeed (formerly Comstock). The input streams contain schemas with the fields Symbol, PricePS (per share), Time, and FeedID.

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 Union.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 Union.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 UnionOut output stream. No output is displayed at this point, but the dequeuer is prepared to receive output. This view eventually shows the output of the application.

  6. In the Manual Input view, select the ComstockIn input stream.

  7. Enter amat, 24, 1, and 0 in the Symbol, PricePS, Time, and FeedID fields, respectively.

  8. Click Send Data, and observe this data appears in the Application Output view:

    Symbol=amat, PricePS=24.0, Time=1, FeedID=0
  9. Select the ReutersIn input stream.

  10. Enter msft, 40, 2, and 1 in the Symbol, PricePS, Time, and FeedID fields, respectively.

  11. Click Send Data, and observe this data appears in the Application Output view:

    Symbol=msft, PricePS=40.0, Time=2, FeedID=1
  12. Enter intc, 24, 3, and 1 in the Symbol, PricePS, Time, and FeedID fields, respectively.

  13. Click Send Data, and observe this data appears in the Application Output view:

    Symbol=intc, PricePS=24.0, Time=3, FeedID=1
  14. Select the ComstockIn input stream.

  15. Enter amat, 23, 4, and 0 in the Symbol, PricePS, Time, and FeedID fields, respectively.

  16. Click Send Data, and observe this data appears in the Application Output view:

    Symbol=amat, PricePS=23.0, Time=4, FeedID=0
  17. Select the ReutersIn input stream.

  18. Enter intc, 22, 5, and 1 in the Symbol, PricePS, Time, and FeedID fields, respectively.

  19. Click Send Data, and observe this data appears in the Application Output view:

    Symbol=intc, PricePS=22.0, Time=5, FeedID=1

    Note that the time in this tuple is before the time in the previous tuple. In other words, the Union operator is agnostic to the order of input tuples. Use a Merge operator if you want to order on a field by using a criterion such as time.

  20. 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.