Building Processes

Implement backend steps and register their code references in process metadata.

Implement a backend step

A BackendStep receives both input and output and returns void. Place this complete class in HelloStep.java:

Java

import com.kingsrook.qqq.backend.core.actions.processes.BackendStep;
import com.kingsrook.qqq.backend.core.model.actions.processes.RunBackendStepInput;
import com.kingsrook.qqq.backend.core.model.actions.processes.RunBackendStepOutput;

public class HelloStep implements BackendStep
{
   @Override
   public void run(RunBackendStepInput input, RunBackendStepOutput output)
   {
      output.addValue("message", "Hello from QQQ");
   }
}

Register the process

Use a QCodeReference to the step class. This fragment belongs in your metadata producer; HelloStep must be in scope.

Java

import java.util.List;
import com.kingsrook.qqq.backend.core.model.metadata.code.QCodeReference;
import com.kingsrook.qqq.backend.core.model.metadata.processes.QBackendStepMetaData;
import com.kingsrook.qqq.backend.core.model.metadata.processes.QProcessMetaData;

QProcessMetaData hello = new QProcessMetaData()
   .withName("hello")
   .withLabel("Hello")
   .withStepList(List.of(new QBackendStepMetaData()
      .withName("greet")
      .withCode(new QCodeReference(HelloStep.class))));

Add the process to your instance. Declare input/output field metadata for values exposed to a frontend step. The sample Greet Interactive process demonstrates input collection, backend execution, and a result screen.

Scheduling and failures

Scheduling is configured through QScheduleMetaData and the application's scheduler lifecycle. Quartz cron syntax is not a five-field Unix cron expression. Select the intended time zone and test the next fire times. Make retries and side effects explicit in your application; process metadata alone does not guarantee safe retry of an external operation.

See the process reference and scheduled jobs.