} else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {
        // never generated empty instance for this type before.
        Object emptyInstance = invokeGeneratorMethod(emptyGenerate);
        emptyInstanceGenerated.put(type.getType(), freshness.get());
        return emptyInstance;
      }
    }
    Method generate = GENERATORS.get(rawType);
    if (generate != null) {

/generators/sir-tests-generator/ "Kotlin Native"
/generators/protobuf/ "Kotlin Build Infrastructure"
# UNKNOWN: /generators/protobufCompare/
/generators/test-generator/ "Kotlin Compiler Core" "Kotlin JVM" "Kotlin Native" "Kotlin Wasm" "Kotlin Common Backend"
/generators/tests/ "Kotlin Compiler Core" "Kotlin JVM" "Kotlin Native" "Kotlin Wasm" "Kotlin Common Backend"

  }

  /*
   * All the ContiguousSet generators below manually reject nulls here. In principle, we'd like to
   * defer that to Range, since it's ContiguousSet.create() that's used to create the sets. However,
   * that gets messy here, and we already have null tests for Range.
   */

  /*
   * These generators also rely on consecutive integer inputs (not necessarily in order, but no
   * holes).

        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {
        // never generated empty instance for this type before.
        Object emptyInstance = invokeGeneratorMethod(emptyGenerate);
        emptyInstanceGenerated.put(type.getType(), freshness.get());
        return emptyInstance;
      }
    }
    Method generate = GENERATORS.get(rawType);
    if (generate != null) {

## OpenAPI Client Generators

There are many tools to generate clients from **OpenAPI**.

A common tool is <a href="https://openapi-generator.tech/" class="external-link" target="_blank">OpenAPI Generator</a>.

public class SortedMultisetTestSuiteBuilder<E> extends MultisetTestSuiteBuilder<E> {
  public static <E> SortedMultisetTestSuiteBuilder<E> using(TestMultisetGenerator<E> generator) {
    SortedMultisetTestSuiteBuilder<E> result = new SortedMultisetTestSuiteBuilder<>();
    result.usingGenerator(generator);
    return result;
  }

  @Override
  public TestSuite createTestSuite() {
    withFeatures(KNOWN_ORDER);

public class SortedMultisetTestSuiteBuilder<E> extends MultisetTestSuiteBuilder<E> {
  public static <E> SortedMultisetTestSuiteBuilder<E> using(TestMultisetGenerator<E> generator) {
    SortedMultisetTestSuiteBuilder<E> result = new SortedMultisetTestSuiteBuilder<>();
    result.usingGenerator(generator);
    return result;
  }

  @Override
  public TestSuite createTestSuite() {
    withFeatures(KNOWN_ORDER);

inputs into the actual types consumed by the connected XDS clients (typically Envoy). This is done by `Generators`, which register a function to build a given type. For example, there is a `RouteGenerator` responsible for building `Routes`. Along with the core Envoy XDS types, there are a few custom Istio types, such as our `NameTable` type used for DNS, as well as debug interfaces.

`Generators` get as input the `Proxy` (a representation of the current client), the current `PushContext` snapshot,...

  }

  /*
   * All the ContiguousSet generators below manually reject nulls here. In principle, we'd like to
   * defer that to Range, since it's ContiguousSet.create() that's used to create the sets. However,
   * that gets messy here, and we already have null tests for Range.
   */

  /*
   * These generators also rely on consecutive integer inputs (not necessarily in order, but no
   * holes).

* <a href="https://github.com/tiangolo/full-stack-flask-couchdb" class="external-link" target="_blank">https://github.com/tiangolo/full-stack-flask-couchdb</a>

And these same full-stack generators were the base of the [**FastAPI** Project Generators](project-generation.md){.internal-link target=_blank}.

!!! info
    Flask-apispec was created by the same Marshmallow developers.

!!! check "Inspired **FastAPI** to"