Emit Suggestion message (#3073)

Contributes to: cucumber/common#2272

Author: mpkorstanje

CHANGELOG.md

@@ -10,6 +10,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- [Core] Emit Suggestion message ([#3073](https://github.com/cucumber/cucumber-jvm/pull/3073) M.P. Korstanje)
+
 ### Fixed
 - [Core] Emit StepMatchArgumentsList for ambiguous steps ([#3066](https://github.com/cucumber/cucumber-jvm/pull/3066) M.P. Korstanje)
 

cucumber-core/src/main/java/io/cucumber/core/backend/Snippet.java

@@ -5,10 +5,21 @@
 import java.lang.reflect.Type;
 import java.text.MessageFormat;
 import java.util.Map;
+import java.util.Optional;
 
 @API(status = API.Status.STABLE)
 public interface Snippet {
 
+    /**
+     * The language of the generated snippet.
+     * 
+     * @see    io.cucumber.messages.types.Snippet#getLanguage()
+     * @return the language of the generated snippet.
+     */
+    default Optional<String> language() {
+        return Optional.empty();
+    }
+
     /**
      * @return a {@link java.text.MessageFormat} template used to generate a
      *         snippet. The template can access the following variables:

cucumber-core/src/main/java/io/cucumber/core/runner/Runner.java

@@ -13,8 +13,9 @@
 import io.cucumber.core.logging.LoggerFactory;
 import io.cucumber.core.snippets.SnippetGenerator;
 import io.cucumber.core.stepexpression.StepTypeRegistry;
+import io.cucumber.messages.types.Envelope;
+import io.cucumber.messages.types.Snippet;
 import io.cucumber.plugin.event.HookType;
-import io.cucumber.plugin.event.Location;
 import io.cucumber.plugin.event.SnippetsSuggestedEvent;
 import io.cucumber.plugin.event.SnippetsSuggestedEvent.Suggestion;
 
@@ -26,11 +27,11 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
-import java.util.stream.Collectors;
 
 import static io.cucumber.core.exception.ExceptionUtils.throwAsUncheckedException;
 import static io.cucumber.core.runner.StackManipulation.removeFrameworkFrames;
 import static java.util.Collections.emptyList;
+import static java.util.stream.Collectors.toList;
 
 public final class Runner {
 
@@ -128,7 +129,7 @@ private List<SnippetGenerator> createSnippetGeneratorsForPickle(StepTypeRegistry
                 .map(Backend::getSnippet)
                 .filter(Objects::nonNull)
                 .map(s -> new SnippetGenerator(s, stepTypeRegistry.parameterTypeRegistry()))
-                .collect(Collectors.toList());
+                .collect(toList());
     }
 
     private void buildBackendWorlds() {
@@ -193,16 +194,28 @@ private PickleStepDefinitionMatch matchStepToStepDefinition(Pickle pickle, Step
     }
 
     private void emitSnippetSuggestedEvent(Pickle pickle, Step step) {
-        List<String> snippets = generateSnippetsForStep(step);
+        List<Snippet> snippets = generateSnippetsForStep(step);
         if (snippets.isEmpty()) {
             return;
         }
-        Suggestion suggestion = new Suggestion(step.getText(), snippets);
-        Location scenarioLocation = pickle.getLocation();
-        Location stepLocation = step.getLocation();
-        SnippetsSuggestedEvent event = new SnippetsSuggestedEvent(bus.getInstant(), pickle.getUri(), scenarioLocation,
-            stepLocation, suggestion);
-        bus.send(event);
+
+        bus.send(new SnippetsSuggestedEvent(
+            bus.getInstant(),
+            pickle.getUri(),
+            pickle.getLocation(),
+            step.getLocation(),
+            new Suggestion(
+                step.getText(),
+                snippets.stream()
+                        .map(Snippet::getCode)
+                        .collect(toList()))));
+
+        bus.send(
+            Envelope.of(
+                new io.cucumber.messages.types.Suggestion(
+                    bus.generateId().toString(),
+                    step.getId(),
+                    snippets)));
     }
 
     private List<HookTestStep> createAfterStepHooks(List<String> tags) {
@@ -219,16 +232,18 @@ private List<HookTestStep> createTestStepsForHooks(
         return hooks.stream()
                 .filter(hook -> hook.matches(tags))
                 .map(hook -> new HookTestStep(bus.generateId(), hookType, new HookDefinitionMatch(hook)))
-                .collect(Collectors.toList());
-    }
-
-    private List<String> generateSnippetsForStep(Step step) {
-        List<String> snippets = new ArrayList<>();
-        for (SnippetGenerator snippetGenerator : snippetGenerators) {
-            List<String> snippet = snippetGenerator.getSnippet(step, runnerOptions.getSnippetType());
-            snippets.addAll(snippet);
-        }
-        return snippets;
+                .collect(toList());
+    }
+
+    private List<Snippet> generateSnippetsForStep(Step step) {
+        return snippetGenerators.stream()
+                .flatMap(generator -> {
+                    String language = generator.getLanguage().orElse("unknown");
+                    return generator.getSnippet(step, runnerOptions.getSnippetType())
+                            .stream()
+                            .map(code -> new Snippet(language, code));
+                })
+                .collect(toList());
     }
 
 }

cucumber-core/src/main/java/io/cucumber/core/snippets/SnippetGenerator.java

@@ -15,6 +15,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -37,6 +38,10 @@ public SnippetGenerator(Snippet snippet, ParameterTypeRegistry parameterTypeRegi
         this.generator = new CucumberExpressionGenerator(parameterTypeRegistry);
     }
 
+    public Optional<String> getLanguage() {
+        return snippet.language();
+    }
+
     public List<String> getSnippet(Step step, SnippetType snippetType) {
         List<GeneratedExpression> generatedExpressions = generator.generateExpressions(step.getText());
         IdentifierGenerator functionNameGenerator = new IdentifierGenerator(snippetType.joiner());

cucumber-core/src/test/java/io/cucumber/core/snippets/TestSnippet.java

@@ -5,9 +5,15 @@
 import java.lang.reflect.Type;
 import java.text.MessageFormat;
 import java.util.Map;
+import java.util.Optional;
 
 public class TestSnippet implements Snippet {
 
+    @Override
+    public Optional<String> language() {
+        return Optional.of("test");
+    }
+
     private int i;
 
     @Override

cucumber-java/src/main/java/io/cucumber/java/AbstractJavaSnippet.java

@@ -5,11 +5,17 @@
 
 import java.lang.reflect.Type;
 import java.util.Map;
+import java.util.Optional;
 
 import static java.util.stream.Collectors.joining;
 
 abstract class AbstractJavaSnippet implements Snippet {
 
+    @Override
+    public Optional<String> language() {
+        return Optional.of("java");
+    }
+
     @Override
     public final String tableHint() {
         return "" +