Overview

UDX types

Example

Build a development environment

Register and use resources

1. Log on to the Realtime Compute for Apache Flink console.
2. In the top navigation bar, click Development.
3. In the left-side navigation pane, click the Resources tab.
4. In the upper-right corner of the Resources pane, click Create Resource.
5. In the Upload Resource dialog box, configure resource parameters.

   Parameter	Description
   Location	You can upload JAR packages only from your machine in the Realtime Compute for Apache Flink console. Note The maximum size of a JAR package that can be uploaded from your machine is 300 MB. If the JAR package exceeds 300 MB, you must upload it to the Object Storage Service (OSS) bucket bound to your cluster or use APIs to upload it.
   Resource	Click Upload Resource and select the resource that you want to reference.
   Resource Name	Enter a name for the resource.
   Resource Description	Enter a resource description.
   Resource Type	Select the type of the resource. The type can be JAR, DICTIONARY, or PYTHON.

6. In the Resources pane, find the new resource, and move the pointer over More in the Actions column.
7. In the drop-down list, select Reference.
8. In the code editor, declare the UDX at the beginning. The following statement is an example:

   CREATE FUNCTION stringLengthUdf AS 'com.hjc.test.blink.sql.udx.StringLengthUdf';

Types of parameters and return values

Obtain parameters of UDXs

UDXs support an optional open(FunctionContext context) method. You can use FunctionContext to pass custom configuration items.

testKey1=lincoln
test.key2=todd

public void open(FunctionContext context) throws Exception {
      String key1 = context.getJobParameter("testKey1", "empty");
      String key2 = context.getJobParameter("test.key2", "empty");
      System.err.println(String.format("end open: key1:%s, key2:%s", key1, key2));
}