[Core] Support custom UUID generators in test runners

With #2703 a faster UUID generator was introduced. And while the
configuration options were added, they were not actually used by
`cucumber-junit`, `cucumber-junit-platform-engine` and
`cucumber-testng`.

cucumber-core/README.md

@@ -53,7 +53,8 @@ cucumber.plugin=                # comma separated plugin strings.
 cucumber.object-factory=        # object factory class name.
                                 # example: com.example.MyObjectFactory
 
-cucumber.uuid-generator=        # UUID generator class name.
+cucumber.uuid-generator         # uuid generator class name of a registered service provider.
+                                # default: io.cucumber.core.eventbus.RandomUuidGenerator
                                 # example: com.example.MyUuidGenerator
 
 cucumber.publish.enabled        # true or false. default: false
@@ -89,12 +90,13 @@ Cucumber emits events on an event bus in many cases:
 - during the feature file parsing
 - when the test scenarios are executed
 
-An event has a UUID. The UUID generator can be configured using the `cucumber.uuid-generator` property:
+An event has a UUID. The UUID generator can be configured using the
+`cucumber.uuid-generator` property:
 
 | UUID generator                                      | Features                                | Performance [Millions UUID/second] | Typical usage example                                                                                                                                                                                                                                                          | 
 |-----------------------------------------------------|-----------------------------------------|------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | io.cucumber.core.eventbus.RandomUuidGenerator       | Thread-safe, collision-free, multi-jvm  | ~1                                 | Reports may be generated on different JVMs at the same time. A typical example would be one suite that tests against Firefox and another against Safari. The exact browser is configured through a property. These are then executed concurrently on different Gitlab runners. |
-| io.cucumber.core.eventbus.IncrementingUuidGenerator | Thread-safe, collision-free, single-jvm | ~130                               | Reports are generated on a single JVM                                                                                                                                                                                                                                          |
+| io.cucumber.core.eventbus.IncrementingUuidGenerator | Thread-safe, collision-free, single-jvm | ~130                               | Reports are generated on a single JVM in a single execution of Cucumber.                                                                                                                                                                                                       |
 
 The performance gain on real projects depends on the feature size.
 

cucumber-core/src/main/java/io/cucumber/core/eventbus/IncrementingUuidGenerator.java

@@ -10,20 +10,20 @@
  * Thread-safe and collision-free UUID generator for single JVM. This is a
  * sequence generator and each instance has its own counter. This generator is
  * about 100 times faster than #RandomUuidGenerator.
- *
- * Properties:
- * - thread-safe
- * - collision-free in the same classloader
- * - almost collision-free in different classloaders / JVMs
- * - UUIDs generated using the instances from the same classloader are sortable
- *
- * UUID version 8 (custom) / variant 2 <a href=
- * "https://www.ietf.org/archive/id/draft-peabody-dispatch-new-uuid-format-04.html#name-uuid-version-8">...</a>
- * <!-- @formatter:off -->
+ * <p>
+ * Properties: - thread-safe - collision-free in the same classloader - almost
+ * collision-free in different classloaders / JVMs - UUIDs generated using the
+ * instances from the same classloader are sortable
+ * <p>
+ * <a href=
+ * "https://www.ietf.org/archive/id/draft-peabody-dispatch-new-uuid-format-04.html#name-uuid-version-8">UUID
+ * version 8 (custom) / variant 2 </a>
+ * 
+ * <pre>
  * |       40 bits      |      8 bits    |  4 bits |    12 bits    |  2 bits | 62 bits |
  * | -------------------| -------------- | ------- | ------------- | ------- | ------- |
  * | LSBs of epoch-time | sessionCounter | version | classloaderId | variant | counter |
- * <!-- @formatter:on -->
+ * </pre>
  */
 public class IncrementingUuidGenerator implements UuidGenerator {
     /**
@@ -84,7 +84,7 @@ public class IncrementingUuidGenerator implements UuidGenerator {
      * classloaderId which produces about 1% collision rate on the
      * classloaderId, and thus can have UUID collision if the epoch-time,
      * session counter and counter have the same values).
-     * 
+     *
      * @param classloaderId the new classloaderId (only the least significant 12
      *                      bits are used)
      * @see                 IncrementingUuidGenerator#classloaderId

cucumber-core/src/main/java/io/cucumber/core/runtime/UuidGeneratorServiceLoader.java

@@ -38,7 +38,7 @@ public UuidGeneratorServiceLoader(Supplier<ClassLoader> classLoaderSupplier, Opt
         this.options = requireNonNull(options);
     }
 
-    UuidGenerator loadUuidGenerator() {
+    public UuidGenerator loadUuidGenerator() {
         Class<? extends UuidGenerator> objectFactoryClass = options.getUuidGeneratorClass();
         ClassLoader classLoader = classLoaderSupplier.get();
         ServiceLoader<UuidGenerator> loader = ServiceLoader.load(UuidGenerator.class, classLoader);

cucumber-junit-platform-engine/README.md

@@ -373,6 +373,10 @@ cucumber.junit-platform.naming-strategy.long.example-name=     # number or pickl
 
 cucumber.plugin=                                               # comma separated plugin strings.
                                                                # example: pretty, json:path/to/report.json
+
+cucumber.uuid-generator                                        # uuid generator class name of a registered service provider.
+                                                               # default: io.cucumber.core.eventbus.RandomUuidGenerator
+                                                               # example: com.example.MyUuidGenerator
  
 cucumber.object-factory=                                       # object factory class name.
                                                                # example: com.example.MyObjectFactory

cucumber-junit-platform-engine/src/main/java/io/cucumber/junit/platform/engine/CucumberEngineExecutionContext.java

@@ -19,12 +19,12 @@
 import io.cucumber.core.runtime.ThreadLocalObjectFactorySupplier;
 import io.cucumber.core.runtime.ThreadLocalRunnerSupplier;
 import io.cucumber.core.runtime.TimeServiceEventBus;
+import io.cucumber.core.runtime.UuidGeneratorServiceLoader;
 import org.apiguardian.api.API;
 import org.junit.platform.engine.ConfigurationParameters;
 import org.junit.platform.engine.support.hierarchical.EngineExecutionContext;
 
 import java.time.Clock;
-import java.util.UUID;
 import java.util.function.Supplier;
 
 import static io.cucumber.core.runtime.SynchronizedEventBus.synchronize;
@@ -48,8 +48,10 @@ CucumberEngineOptions getOptions() {
 
     private CucumberExecutionContext createCucumberExecutionContext() {
         Supplier<ClassLoader> classLoader = CucumberEngineExecutionContext.class::getClassLoader;
+        UuidGeneratorServiceLoader uuidGeneratorServiceLoader = new UuidGeneratorServiceLoader(classLoader, options);
+        EventBus bus = synchronize(
+            new TimeServiceEventBus(Clock.systemUTC(), uuidGeneratorServiceLoader.loadUuidGenerator()));
         ObjectFactoryServiceLoader objectFactoryServiceLoader = new ObjectFactoryServiceLoader(classLoader, options);
-        EventBus bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID));
         Plugins plugins = new Plugins(new PluginFactory(), options);
         ExitStatus exitStatus = new ExitStatus(options);
         plugins.addPlugin(exitStatus);

cucumber-junit/src/main/java/io/cucumber/junit/Cucumber.java

@@ -23,6 +23,7 @@
 import io.cucumber.core.runtime.ThreadLocalObjectFactorySupplier;
 import io.cucumber.core.runtime.ThreadLocalRunnerSupplier;
 import io.cucumber.core.runtime.TimeServiceEventBus;
+import io.cucumber.core.runtime.UuidGeneratorServiceLoader;
 import org.apiguardian.api.API;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -38,7 +39,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.UUID;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
@@ -146,11 +146,14 @@ public Cucumber(Class<?> clazz) throws InitializationError {
                 .parse(CucumberProperties.fromSystemProperties())
                 .build(junitEnvironmentOptions);
 
-        this.bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID));
+        Supplier<ClassLoader> classLoader = ClassLoaders::getDefaultClassLoader;
+        UuidGeneratorServiceLoader uuidGeneratorServiceLoader = new UuidGeneratorServiceLoader(classLoader,
+            runtimeOptions);
+        this.bus = synchronize(
+            new TimeServiceEventBus(Clock.systemUTC(), uuidGeneratorServiceLoader.loadUuidGenerator()));
 
         // Parse the features early. Don't proceed when there are lexer errors
         FeatureParser parser = new FeatureParser(bus::generateId);
-        Supplier<ClassLoader> classLoader = ClassLoaders::getDefaultClassLoader;
         FeaturePathFeatureSupplier featureSupplier = new FeaturePathFeatureSupplier(classLoader, runtimeOptions,
             parser);
         List<Feature> features = featureSupplier.get();

cucumber-testng/src/main/java/io/cucumber/testng/TestNGCucumberRunner.java

@@ -23,11 +23,11 @@
 import io.cucumber.core.runtime.ThreadLocalObjectFactorySupplier;
 import io.cucumber.core.runtime.ThreadLocalRunnerSupplier;
 import io.cucumber.core.runtime.TimeServiceEventBus;
+import io.cucumber.core.runtime.UuidGeneratorServiceLoader;
 import org.apiguardian.api.API;
 
 import java.time.Clock;
 import java.util.List;
-import java.util.UUID;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
@@ -98,9 +98,10 @@ public TestNGCucumberRunner(Class<?> clazz, CucumberPropertiesProvider propertie
                 .enablePublishPlugin()
                 .build(environmentOptions);
 
-        EventBus bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID));
-
         Supplier<ClassLoader> classLoader = ClassLoaders::getDefaultClassLoader;
+        UuidGeneratorServiceLoader uuidGeneratorServiceLoader = new UuidGeneratorServiceLoader(classLoader, runtimeOptions);
+        EventBus bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), uuidGeneratorServiceLoader.loadUuidGenerator()));
+
         FeatureParser parser = new FeatureParser(bus::generateId);
         FeaturePathFeatureSupplier featureSupplier = new FeaturePathFeatureSupplier(classLoader, runtimeOptions,
             parser);