Loop Sample

About This Sample

This sample application takes input from a provided feed simulation. It splits incoming trades into smaller trades of qty = split_size and, if necessary, adds an additional trade for the remainder of qty/split_size. The filter operator is a required part of creating a conditional loop.

Arcs usually take their schemas from upstream operators. But the arc that creates the loop in loop.sbapp requires an explicit schema. As a best practice, when possible, re-use the named schema from the incoming stream (in this case, InputStream) for the looping arc's schema.

Importing This Sample into StreamBase Studio

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

  • From the top-level menu, select File>Import Samples and Community Content.

  • Enter loop to narrow the list of options.

  • Select the Demonstrates a simple loop connection sample from the Applications category.

  • Click Import Now.

StreamBase Studio creates a project for the sample.

Running This Sample in StreamBase Studio

To run this sample:

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

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

    If the red marks do not resolve themselves after a minute, select the project, right-click, and select Maven>Update Project from the context menu.

  2. Open the src/main/eventflow/packageName folder.

  3. Open the loop.sbapp file and click the Run button. This opens the SB Test/Debug perspective and starts the module.

  4. Open the Feed Simulations tab.

  5. Select the loop-feedsim.sbfs feed simulation file and click Run.

  6. Observe the tuples emitted from the SmallTradesOut stream.

  7. When done, press F9 or click the Terminate EventFlow Fragment 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.


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:


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