An Input Adapter is a program, running in the same server process as your StreamBase application, that converts data from an external source to the StreamBase tuple protocol. After adding an Input Adapter to an EventFlow in StreamBase Studio, select its icon on your canvas and open its Properties view. Then configure its properties, as described in this topic.
Name: Every application component must have a unique name. Use this field to specify or change the component's name. The name must contain only alphabetic characters, numbers, and underscores, and no hyphens or other special characters. The first character must be alphabetic or an underscore.
Adapter Name: This field shows the full formal name of the Input Adapter.
Class: This field shows the fully qualified Java class
name that implements the functionality of this Input Adapter. (In StreamSQL
applications, this is the name to use with the APPLY
statement.)
Start with application: This checkbox is checked by
default, which means that the Input Adapter starts along with the
StreamBase application that contains it. Unchecking this box causes the
adapter to not start when the application starts, in which case it must be explicitly
started with the sbadmin resume operatorName command. With this
option disabled, the Input Adapter does not start even if the application as a whole
is suspended and later resumed.
Enable Error Output Port: Check this box to add an Error Port to this component. In the EventFlow canvas, the Error Port shows as a red output port, always the last port for the component. See Using Error Ports and Error Streams to learn about Error Ports.
Description: Optionally, enter a description to briefly describe the component's purpose and function. In the EventFlow canvas, you can see the description by pressing Ctrl while the component's tooltip is displayed.
The Adapter Settings tab is where you specify the unique properties of each adapter. Refer to the Properties table of each adapter's topic in the Adapters Guide for a list of the properties for each adapter.
The Edit Schema tab allows you to specify the schema (field name, lengths, data types) of the inbound data for this adapter. This functionality is similar to the Edit Schema tab for Input Streams, as described in Defining Input Streams.
- Run this component in a separate thread
-
This option causes the server to process the component's requests concurrently with other processing in the application. You can distribute the processing of the threads automatically across multiple processors on an SMP machine.
If this is a compute-intensive component and you know that it can run without data dependencies on other components in the StreamBase application, you may be able to improve performance by enabling this option.
Caution
These features are not suitable for every application. For details, see Execution Order, Concurrency, and Parallelism. It includes important guidelines for the use of these features.
- Run in parallel threads
-
If you checked the first option, you can also choose this option, which causes the server to run multiple instances of this component. That is, each instance runs in its own thread. At run time, tuples are dispatched to particular instances based on the Key Expression value (which must evaluate to an int).