Fix diagram generation for multiple languages in source model

Author: atextor

core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/diagram/AspectModelDiagramGenerator.java

@@ -102,13 +102,18 @@ public AspectModelDiagramGenerator( final Aspect aspect, final DiagramGeneration
 
    @Override
    public Stream<DiagramArtifact> generate() {
-      final String artifactName = "%s_%s.%s".formatted( aspect().getName(), config.language().toLanguageTag(),
-            config.format().toString().toLowerCase() );
-      final String svg = generateSvg();
-      final byte[] content = config.format() == DiagramGenerationConfig.Format.SVG
-            ? svg.getBytes( StandardCharsets.UTF_8 )
-            : generatePng( svg );
-      return Stream.of( new DiagramArtifact( artifactName, content ) );
+      final Set<Locale> targetLanguages = config.language() == null
+            ? LanguageCollector.collectUsedLanguages( aspect() )
+            : Set.of( config.language() );
+      return targetLanguages.stream().map( language -> {
+         final String artifactName = "%s_%s.%s".formatted( aspect().getName(), language.toLanguageTag(),
+               config.format().toString().toLowerCase() );
+         final String svg = generateSvg();
+         final byte[] content = config.format() == DiagramGenerationConfig.Format.SVG
+               ? svg.getBytes( StandardCharsets.UTF_8 )
+               : generatePng( svg );
+         return new DiagramArtifact( artifactName, content, language );
+      } );
    }
 
    private InputStream getInputStream( final String resource ) {
@@ -251,7 +256,11 @@ public void generateDiagrams( final Format outputFormat, final Function<String,
                .language( language )
                .format( outputFormat == Format.PNG ? DiagramGenerationConfig.Format.PNG : DiagramGenerationConfig.Format.SVG )
                .build();
-         final DiagramArtifact diagramArtifact = new AspectModelDiagramGenerator( aspect(), config ).singleResult();
+         final DiagramArtifact diagramArtifact = new AspectModelDiagramGenerator( aspect(), config )
+               .generate()
+               .filter( artifact -> artifact.language().equals( language ) )
+               .findFirst()
+               .orElseThrow();
          IOUtils.copy( new ByteArrayInputStream( diagramArtifact.getContent() ), nameMapper.apply( diagramArtifact.getId() ) );
       }
    }

core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/diagram/DiagramArtifact.java

@@ -13,10 +13,24 @@
 
 package org.eclipse.esmf.aspectmodel.generator.diagram;
 
+import java.util.Locale;
+
 import org.eclipse.esmf.aspectmodel.generator.BinaryArtifact;
+import org.eclipse.esmf.aspectmodel.generator.LocalizedArtifact;
+
+/**
+ * Generation artifact that represents a diagram
+ */
+public class DiagramArtifact extends BinaryArtifact implements LocalizedArtifact {
+   private final Locale language;
 
-public class DiagramArtifact extends BinaryArtifact {
-   public DiagramArtifact( final String id, final byte[] content ) {
+   public DiagramArtifact( final String id, final byte[] content, final Locale language ) {
       super( id, content );
+      this.language = language;
+   }
+
+   @Override
+   public Locale language() {
+      return language;
    }
 }

core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/diagram/DiagramGenerationConfig.java

@@ -37,8 +37,5 @@ public static String allValues() {
       if ( format == null ) {
          format = Format.SVG;
       }
-      if ( language == null ) {
-         language = Locale.ENGLISH;
-      }
    }
 }

core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/docu/AspectModelDocumentationGenerator.java

@@ -104,7 +104,7 @@ public Stream<DocumentationArtifact> generate() {
          source = insertAspectModelDiagram( source, language );
          source = insertStaticPlaceholders( source );
          source = insertCustomCss( source );
-         return new DocumentationArtifact( artifactName, source );
+         return new DocumentationArtifact( artifactName, source, language );
       } );
    }
 

core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/docu/DocumentationArtifact.java

@@ -13,10 +13,24 @@
 
 package org.eclipse.esmf.aspectmodel.generator.docu;
 
+import java.util.Locale;
+
+import org.eclipse.esmf.aspectmodel.generator.LocalizedArtifact;
 import org.eclipse.esmf.aspectmodel.generator.StringArtifact;
 
-public class DocumentationArtifact extends StringArtifact {
-   public DocumentationArtifact( final String id, final String content ) {
+/**
+ * Generation artifact that represents documentation for an Aspect Model
+ */
+public class DocumentationArtifact extends StringArtifact implements LocalizedArtifact {
+   private final Locale language;
+
+   public DocumentationArtifact( final String id, final String content, final Locale language ) {
       super( id, content );
+      this.language = language;
+   }
+
+   @Override
+   public Locale language() {
+      return language;
    }
 }

core/esmf-aspect-model-document-generators/src/test/java/org/eclipse/esmf/aspectmodel/generator/diagram/AspectModelDiagramGeneratorTest.java

@@ -16,12 +16,18 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatCode;
 
+import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
+import java.util.function.Function;
 
 import org.eclipse.esmf.metamodel.Aspect;
+import org.eclipse.esmf.metamodel.AspectModel;
 import org.eclipse.esmf.test.TestAspect;
 import org.eclipse.esmf.test.TestResources;
 
+import org.apache.commons.io.output.NullOutputStream;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.EnumSource;
 import org.junit.jupiter.params.provider.ValueSource;
@@ -56,4 +62,27 @@ void generateDiagramsShouldReturnUtf8StringRegardlessOfPlatformEncoding( final S
          System.setProperty( "file.encoding", platformEncoding );
       }
    }
+
+   @Test
+   void testGenerateDiagramsInMultipleLanguages() throws IOException {
+      final AspectModel aspectModel = TestResources.load( TestAspect.ASPECT_WITH_ENGLISH_AND_GERMAN_DESCRIPTION );
+      final AspectModelDiagramGenerator generator = new AspectModelDiagramGenerator(
+            aspectModel.aspect(), DiagramGenerationConfigBuilder.builder().format( DiagramGenerationConfig.Format.SVG ).build() );
+      assertThat( generator.generate().toList() ).size().isEqualTo( 2 );
+
+      // Test legacy API
+      final AspectModelDiagramGenerator generator2 = new AspectModelDiagramGenerator( aspectModel.aspect() );
+      class GenerationFunction implements Function<String, OutputStream> {
+         int count = 0;
+
+         @Override
+         public OutputStream apply( final String name ) {
+            count++;
+            return NullOutputStream.INSTANCE;
+         }
+      }
+      final GenerationFunction nameMapper = new GenerationFunction();
+      generator2.generateDiagrams( AspectModelDiagramGenerator.Format.SVG, nameMapper );
+      assertThat( nameMapper.count ).isEqualTo( 2 );
+   }
 }

core/esmf-aspect-model-generator/src/main/java/org/eclipse/esmf/aspectmodel/generator/LocalizedArtifact.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Robert Bosch Manufacturing Solutions GmbH
+ *
+ * See the AUTHORS file(s) distributed with this work for additional
+ * information regarding authorship.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
+package org.eclipse.esmf.aspectmodel.generator;
+
+import java.util.Locale;
+
+/**
+ * Interface that indicates that an artifact is also localized
+ */
+public interface LocalizedArtifact {
+   Locale language();
+}