Smithy Generator Experiment

java-codegen/build.gradle.kts

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+plugins {
+    java
+    id("com.github.johnrengelman.shadow") version "7.1.2"
+}
+
+group = "org.opensearch.client"
+version = "2.1.1-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    val smithyVersion = "1.26.1"
+    val junitVersion = "5.8.2"
+
+    implementation("org.jetbrains:annotations:24.0.0")
+
+    implementation("software.amazon.smithy:smithy-codegen-core:$smithyVersion")
+    implementation("software.amazon.smithy:smithy-waiters:$smithyVersion")
+    implementation("software.amazon.smithy:smithy-rules-engine:$smithyVersion")
+    implementation("software.amazon.smithy:smithy-aws-traits:$smithyVersion")
+    implementation("software.amazon.smithy:smithy-protocol-test-traits:$smithyVersion")
+
+    // Test dependencies
+    testImplementation("org.junit.jupiter:junit-jupiter:$junitVersion")
+}
+
+tasks.getByName<Test>("test") {
+    useJUnitPlatform()
+}

java-codegen/src/main/java/org/opensearch/client/codegen/CodegenVisitor.java

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+package org.opensearch.client.codegen;
+
+import org.opensearch.client.codegen.core.GenerationContext;
+import org.opensearch.client.codegen.core.JavaDelegator;
+import org.opensearch.client.codegen.core.JavaSymbolProvider;
+import org.opensearch.client.codegen.core.RenderingContext;
+import org.opensearch.client.codegen.model.OperationNormalizer;
+import org.opensearch.client.codegen.render.ServiceGenerator;
+import org.opensearch.client.codegen.render.StructureGenerator;
+import software.amazon.smithy.build.FileManifest;
+import software.amazon.smithy.build.PluginContext;
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.knowledge.HttpBindingIndex;
+import software.amazon.smithy.model.neighbor.Walker;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.model.shapes.Shape;
+import software.amazon.smithy.model.shapes.ShapeVisitor;
+import software.amazon.smithy.model.shapes.StructureShape;
+import software.amazon.smithy.model.transform.ModelTransformer;
+
+import java.util.logging.Logger;
+
+public class CodegenVisitor extends ShapeVisitor.Default<Void> {
+    private static final Logger LOGGER = Logger.getLogger(CodegenVisitor.class.getName());
+    private final OpenSearchJavaSettings settings;
+    private final Model model;
+    private final ServiceShape service;
+    private final JavaSymbolProvider symbolProvider;
+    private final JavaDelegator writers;
+    private final GenerationContext generationContext;
+
+
+    public CodegenVisitor(PluginContext context) {
+        settings = OpenSearchJavaSettings.from(context.getModel(), context.getSettings());
+        model = baselineTransform(context.getModel());
+        service = settings.getService(model);
+        FileManifest fileManifest = context.getFileManifest();
+        symbolProvider = new JavaSymbolProvider(model);
+        HttpBindingIndex httpBindingIndex = HttpBindingIndex.of(model);
+        writers = new JavaDelegator(fileManifest, symbolProvider);
+        generationContext = new GenerationContext(model, symbolProvider, httpBindingIndex, settings);
+    }
+
+    private Model baselineTransform(Model model) {
+        model = ModelTransformer.create().flattenAndRemoveMixins(model);
+        model = ModelTransformer.create().copyServiceErrorsToOperations(model, settings.getService(model));
+        model = OperationNormalizer.transform(model);
+        return model;
+    }
+
+    public void execute() {
+        new Walker(model)
+                .walkShapes(service)
+                .forEach(s -> s.accept(this));
+        writers.flushWriters();
+    }
+
+    @Override
+    protected Void getDefault(Shape shape) {
+        return null;
+    }
+
+    @Override
+    public Void serviceShape(ServiceShape shape) {
+        LOGGER.info("Generating structure " + shape.getId().getName());
+
+        writers.useShapeWriter(shape, w -> {
+            RenderingContext<ServiceShape> ctx = new RenderingContext<>(generationContext, w, shape);
+            new ServiceGenerator(ctx).render();
+        });
+
+        Symbol asyncSymbol = symbolProvider.serviceAsyncSymbol(shape);
+        writers.useSymbolWriter(asyncSymbol, w -> {
+            RenderingContext<ServiceShape> ctx = new RenderingContext<>(generationContext, w, shape, asyncSymbol);
+            new ServiceGenerator(ctx).render();
+        });
+
+        return null;
+    }
+
+    @Override
+    public Void structureShape(StructureShape shape) {
+        writers.useShapeWriter(shape, w -> {
+            RenderingContext<StructureShape> ctx = new RenderingContext<>(generationContext, w, shape);
+            new StructureGenerator(ctx).render();
+        });
+
+        return null;
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/OpenSearchJavaCodegenPlugin.java

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+package org.opensearch.client.codegen;
+
+import software.amazon.smithy.build.PluginContext;
+import software.amazon.smithy.build.SmithyBuildPlugin;
+
+public class OpenSearchJavaCodegenPlugin implements SmithyBuildPlugin {
+    @Override
+    public String getName() {
+        return "opensearch-java";
+    }
+
+    @Override
+    public void execute(PluginContext context) {
+        new CodegenVisitor(context).execute();
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/OpenSearchJavaSettings.java

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+package org.opensearch.client.codegen;
+
+import software.amazon.smithy.codegen.core.CodegenException;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.node.ObjectNode;
+import software.amazon.smithy.model.node.StringNode;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.model.shapes.Shape;
+import software.amazon.smithy.model.shapes.ShapeId;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+public class OpenSearchJavaSettings {
+    private static final Logger LOGGER = Logger.getLogger(OpenSearchJavaSettings.class.getName());
+    private static final String SERVICE = "service";
+    private final ShapeId service;
+
+    private OpenSearchJavaSettings(ShapeId service) {
+        this.service = service;
+    }
+
+    public ServiceShape getService(Model model) {
+        return model.expectShape(service, ServiceShape.class);
+    }
+
+    public static OpenSearchJavaSettings from(Model model, ObjectNode config) {
+        config.warnIfAdditionalProperties(Collections.singletonList(SERVICE));
+
+        ShapeId service = config.getStringMember(SERVICE).map(StringNode::expectShapeId).orElseGet(() -> inferService(model));
+
+        return new OpenSearchJavaSettings(service);
+    }
+
+    private static ShapeId inferService(Model model) {
+        List<ShapeId> services = model.shapes(ServiceShape.class).map(Shape::getId).sorted().collect(Collectors.toList());
+
+        if (services.isEmpty()) {
+            throw new CodegenException("Cannot infer a service to generate because the model does not contain any service shapes");
+        }
+        if (services.size() > 1) {
+            throw new CodegenException("Cannot infer a service to generate because the model contains multiple service shapes: " + services);
+        }
+
+        ShapeId service = services.get(0);
+        LOGGER.info("Inferring service to generate as: " + service);
+        return service;
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/core/CodegenContext.java

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+package org.opensearch.client.codegen.core;
+
+import org.opensearch.client.codegen.OpenSearchJavaSettings;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.knowledge.HttpBindingIndex;
+
+public interface CodegenContext {
+    Model getModel();
+
+    SymbolProvider getSymbolProvider();
+
+    HttpBindingIndex getHttpBindingIndex();
+
+    OpenSearchJavaSettings getSettings();
+}

java-codegen/src/main/java/org/opensearch/client/codegen/core/GenerationContext.java

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+package org.opensearch.client.codegen.core;
+
+import org.opensearch.client.codegen.OpenSearchJavaSettings;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.model.Model;
+import software.amazon.smithy.model.knowledge.HttpBindingIndex;
+
+public class GenerationContext implements CodegenContext {
+    private final Model model;
+    private final SymbolProvider symbolProvider;
+    private final HttpBindingIndex httpBindingIndex;
+    private final OpenSearchJavaSettings settings;
+
+    public GenerationContext(Model model, SymbolProvider symbolProvider, HttpBindingIndex httpBindingIndex, OpenSearchJavaSettings settings) {
+        this.model = model;
+        this.symbolProvider = symbolProvider;
+        this.httpBindingIndex = httpBindingIndex;
+        this.settings = settings;
+    }
+
+    @Override
+    public Model getModel() {
+        return model;
+    }
+
+    @Override
+    public SymbolProvider getSymbolProvider() {
+        return symbolProvider;
+    }
+
+    @Override
+    public HttpBindingIndex getHttpBindingIndex() {
+        return httpBindingIndex;
+    }
+
+    @Override
+    public OpenSearchJavaSettings getSettings() {
+        return settings;
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/core/ImportStatements.java

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+package org.opensearch.client.codegen.core;
+
+import software.amazon.smithy.codegen.core.CodegenException;
+import software.amazon.smithy.codegen.core.ImportContainer;
+import software.amazon.smithy.codegen.core.Symbol;
+
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class ImportStatements implements ImportContainer {
+    private final String packageName;
+    private final HashSet<ImportStatement> imports = new HashSet<>();
+
+    public ImportStatements(String packageName) {
+        this.packageName = packageName;
+    }
+
+    @Override
+    public void importSymbol(Symbol symbol, String alias) {
+        String name = symbol.getName();
+        String namespace = symbol.getNamespace();
+
+        if (!name.equals(alias)) {
+            throw new CodegenException("Java does not allow import aliasing");
+        }
+
+        if (!namespace.isEmpty() && !namespace.equals(packageName)) {
+            imports.add(new ImportStatement(namespace, name));
+        }
+    }
+
+    @Override
+    public String toString() {
+        return imports
+                .stream()
+                .map(ImportStatement::toString)
+                .sorted()
+                .collect(Collectors.joining("\n"));
+    }
+
+    private static class ImportStatement {
+        private final String packageName;
+        private final String symbolName;
+
+        public ImportStatement(String packageName, String symbolName) {
+            this.packageName = packageName;
+            this.symbolName = symbolName;
+        }
+
+        @Override
+        public String toString() {
+            return "import " + packageName + "." + symbolName + ";";
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            ImportStatement that = (ImportStatement) o;
+            return Objects.equals(packageName, that.packageName) && Objects.equals(symbolName, that.symbolName);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(packageName, symbolName);
+        }
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/core/JavaDelegator.java

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+package org.opensearch.client.codegen.core;
+
+import software.amazon.smithy.build.FileManifest;
+import software.amazon.smithy.codegen.core.Symbol;
+import software.amazon.smithy.codegen.core.SymbolProvider;
+import software.amazon.smithy.codegen.core.WriterDelegator;
+import software.amazon.smithy.model.shapes.Shape;
+
+import java.util.function.Consumer;
+
+public class JavaDelegator {
+    private final WriterDelegator<JavaWriter> inner;
+
+    public JavaDelegator(FileManifest fileManifest, SymbolProvider symbolProvider) {
+        inner = new WriterDelegator<>(fileManifest, symbolProvider, JavaWriter.factory());
+    }
+
+    public void useShapeWriter(Shape shape, Consumer<JavaWriter> writerConsumer) {
+        inner.useShapeWriter(shape, writerConsumer);
+    }
+
+    public void useSymbolWriter(Symbol symbol, Consumer<JavaWriter> writerConsumer) {
+        inner.useFileWriter(symbol.getDefinitionFile(), symbol.getNamespace(), writerConsumer);
+    }
+
+    public void flushWriters() {
+        inner.flushWriters();
+    }
+}

java-codegen/src/main/java/org/opensearch/client/codegen/core/JavaReservedWords.java

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+package org.opensearch.client.codegen.core;
+
+import software.amazon.smithy.codegen.core.ReservedWords;
+import software.amazon.smithy.codegen.core.ReservedWordsBuilder;
+
+public class JavaReservedWords {
+    private static final String[] HARD_RESERVED_WORDS = {
+            "null"
+    };
+    private static final ReservedWords INSTANCE;
+
+    static {
+        ReservedWordsBuilder builder = new ReservedWordsBuilder();
+        for (String word : HARD_RESERVED_WORDS) {
+            builder.put(word, "_" + word);
+        }
+        INSTANCE = builder.build();
+    }
+
+    public static ReservedWords instance() {
+        return INSTANCE;
+    }
+}