ReadTable API Sample

Introduction

This sample provides Java code that illustrates the StreamBaseClient.readTable()method, which is used to display all or a specified number of rows from a Query Table or Materialized Window. The Java code is provided in the ReadTableClient.java program in the java-src folder.

The sample contains an EventFlow application, ReadTable.sbapp that contains the following elements:

A local Query Table named SimpleTable.
A module reference to ReadTableModule.sbapp, which contains a shared table named SharedTable.
A module reference to ReadTableModuleWithPlaceholder.sbapp, which contains a placeholder table named PlaceholderTable that is mapped to ConcreteTable.
A materialized window named MatWindow.

The sample demonstrates the ability to retrieve rows from any of these tables, using the following paths at runtime:

[containername.]SimpleTable

[containername.]ReadTableModuleRef.SharedTable

[containername.]ReadTableModuleWithPlaceholderRef.PlaceholderTable

[containername.]ConcreteTable

[containername.]MatWindow

where containername is optional if you run ReadTable.sbapp in the default container named default, but must be present for non-default container names.

You run this sample in two steps:

Run the ReadTable.sbapp application.

On startup, a CSV File Reader adapter populates all tables and the Materialized Window with the same contents, which are read from the file InitialData.txt. (You can supplement this populated data by sending tuples to the InsertToAllTables input stream.) The application then awaits further input or a client connection.
Run the ReadTableClient.java program as a Java application. This StreamBase client program connects to the ReadTable.sbapp application, reads values from its various table constructs, and prints Its output to the console.

Running This Sample in StreamBase Studio

Follow these steps:

In the Package Explorer view, double-click to open the ReadTable.sbapp application. Make sure the application is the currently active tab in the EventFlow Editor.
Click the Run button. This opens the SB Test/Debug perspective and starts the application.

Notice in the Application Output view the set of key-value pairs that was used to populate the tables.
Return to the SB Authoring perspective.
In the Package Explorer view, open the java-src folder tree to expose the ReadTableClient.java file.
Right-click the ReadTableClient.java file and from the context menu, select Run As → Java Application.
Observe the results of the Java program in the Console view.
When done, press F9 or click the Stop Running Application button.

Running This Sample 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.

Open two terminal windows on UNIX, or two StreamBase Command Prompt s on Windows. In each window, navigate to your workspace copy of the sample.
In window 1, start the EventFlow application with the following command:
```
sbd ReadTable.sbapp
```

In window 2, run the provided ReadTableClient program with the following commands:

For Windows

set CLASSPATH=%CLASSPATH%;.\java-bin
java com.streambase.sample.ReadTableClient

For UNIX

export CLASSPATH=`sb-config --classpath`:./java-bin
java com.streambase.sample.ReadTableClient

While the EventFlow application is running, you can also invoke the readTable subcommand of the sbc and jsbc commands. Use sbc list -m to get a list of available table names. This returns, in part:
```
table   ConcreteTable
table   MatWindow
table   ReadTableModuleRef.SharedTable
table   ReadTableModuleWithPlaceholderRef.PlaceholderTable
table   SimpleTable
```

Type commands using the following syntax:

sbc readTable --all containername.TableName

For example, omitting the name of the default container:

sbc readTable --all ConcreteTable
sbc readTable --all ReadTableModuleRef.SharedTable

When done, enter this command in window 2 to close the EventFlow application:
```
sbadmin shutdown
```

Importing This Sample into StreamBase Studio

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

From the top menu, click File → Load StreamBase Sample.
Type table in the search field to narrow the list.
From the Client Libraries category, select the Read Query Tables sample.
Click OK.

StreamBase Studio creates a project for this sample.

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 the permission problems that can occur when trying to work with the initially installed location of the sample. The default workspace location for this sample is:

studio-workspace/sample_ReadTable

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/ReadTable

See Default Installation Directories for the location of streambase-install-dir on your system. This location may require administrator privileges for write access, depending on your platform.