Demo data

Providing example datasets is a good way to help consumers understand the expected input of your model. This page describes how to provide dedicated support for exposing demo data.

1. Generating demo data

To provide consumers of your model with example datasets, implement the DemoDataGenerator interface. This interface requires you to implement 2 methods:

  • demoMetaData(): returns a list of metadata, listing all the different datasets available.

  • generateDemoData(String demoDataId): generates the dataset with the given id, usually retrieved from the metadata.

Implementations of this interface must be dependency free meaning simple instantiation (even with reflection) of this class is enough to generate demo data.

  • Java

  • Kotlin

@ApplicationScoped
public class TimetableDemoDataGenerator implements DemoDataGenerator {

    public enum DemoDataKind {
        BASIC(
            new DemoMetaData("BASIC", "SHORT_DESCRIPTION", "LONG_DESCRIPTION", List.of("TAGS"),
                List.of()),
            DemoDataKind::generateBasicDemoData // could also delegate to another class instead
        ),
        COMPLEX_SET(
            new DemoMetaData("COMPLEX_SET", "SHORT_DESCRIPTION", "LONG_DESCRIPTION", List.of("TAGS"),
                List.of()),
            DemoDataKind::generateComplexSet
        );

        private final DemoMetaData metaData;
        private final Function<DemoDataKind, ModelRequest<TimetableInput, TimetableConfigOverrides>> requestFunction;

        DemoDataKind(DemoMetaData metaData,
                Function<DemoDataKind, ModelRequest<TimetableInput, TimetableConfigOverrides>> requestFunction) {
            this.metaData = metaData;
            this.requestFunction = requestFunction;
        }

        public DemoMetaData getMetaData() {
            return metaData;
        }

        public DemoData getDemoData() {
            return new DemoData(metaData, requestFunction.apply(this));
        }

        public ModelRequest<TimetableInput, TimetableConfigOverrides> generateBasicDemoData() {
            // Generate basic request.
        }

        public ModelRequest<TimetableInput, TimetableConfigOverrides> generateComplexSet() {
            // Generate complex request.
        }
    }

    @Override
    public List<DemoMetaData> demoMetaData() {
        return Stream.of(DemoDataKind.values())
                .map(demoDataKind -> demoDataKind.getMetaData())
                .toList();
    }

    @Override
    public DemoData generateDemoData(String demoDataId) {
        return DemoDataKind.fromString(demoDataId).getDemoData();
    }
}
@ApplicationScoped
class TimetableDemoDataGenerator : DemoDataGenerator {

    enum class DemoDataKind(
        private val metaData: DemoMetaData,
        private val requestFunction: (DemoDataKind) -> ModelRequest<TimetableInput, TimetableConfigOverrides>
    ) {
        BASIC(
            DemoMetaData("BASIC", "SHORT_DESCRIPTION", "LONG_DESCRIPTION", listOf("TAGS"), listOf()),
            { it.generateBasicDemoData() } // could also delegate to another class instead
        ),
        COMPLEX_SET(
            DemoMetaData("COMPLEX_SET", "SHORT_DESCRIPTION", "LONG_DESCRIPTION", listOf("TAGS"), listOf()),
            { it.generateComplexSet() }
        );

        fun getMetaData(): DemoMetaData = metaData

        fun getDemoData(): DemoData = DemoData(metaData, requestFunction(this))

        fun generateBasicDemoData(): ModelRequest<TimetableInput, TimetableConfigOverrides> {
            return TODO("Generate basic request.")
        }

        fun generateComplexSet(): ModelRequest<TimetableInput, TimetableConfigOverrides> {
            return TODO("Generate complex request.")
        }
    }

    override fun demoMetaData(): List<DemoMetaData> {
        return DemoDataKind.entries.map { it.getMetaData() }
    }

    override fun generateDemoData(demoDataId: String): DemoData {
        return DemoDataKind.fromString(demoDataId).getDemoData()
    }
}

With this interface implemented, Timefold Solver will automatically expose these methods as REST endpoints:

  • GET /<root>/demo-data: Retrieve all available demo dataset ids.

  • GET /<root>/demo-data/{demoDataId}: Retrieve the demo dataset with the given identifier