[composer][samplecode]Implement Setting Class Header Comment Sample Code

src/main/java/com/google/api/generator/gapic/composer/BUILD.bazel

@@ -15,8 +15,10 @@ java_library(
     deps = [
         "//:service_config_java_proto",
         "//src/main/java/com/google/api/generator/engine/ast",
+        "//src/main/java/com/google/api/generator/engine/writer",
         "//src/main/java/com/google/api/generator/gapic:status_java_proto",
         "//src/main/java/com/google/api/generator/gapic/model",
+        "//src/main/java/com/google/api/generator/gapic/composer/samplecode",
         "//src/main/java/com/google/api/generator/gapic/utils",
         "@com_google_api_api_common//jar",
         "@com_google_api_gax_java//gax",

src/main/java/com/google/api/generator/gapic/composer/ServiceSettingsClassComposer.java

@@ -54,6 +54,7 @@
 import com.google.api.generator.gapic.model.GapicClass.Kind;
 import com.google.api.generator.gapic.model.Message;
 import com.google.api.generator.gapic.model.Method;
+import com.google.api.generator.gapic.model.Method.Stream;
 import com.google.api.generator.gapic.model.Service;
 import com.google.api.generator.gapic.utils.JavaStyle;
 import com.google.common.base.Preconditions;
@@ -101,7 +102,7 @@ public GapicClass generate(Service service, Map<String, Message> ignore) {
     ClassDefinition classDef =
         ClassDefinition.builder()
             .setPackageString(pakkage)
-            .setHeaderCommentStatements(createClassHeaderComments(service))
+            .setHeaderCommentStatements(createClassHeaderComments(service, types.get(className)))
             .setAnnotations(createClassAnnotations())
             .setScope(ScopeNode.PUBLIC)
             .setName(className)
@@ -119,11 +120,20 @@ public GapicClass generate(Service service, Map<String, Message> ignore) {
     return GapicClass.create(kind, classDef);
   }
 
-  private static List<CommentStatement> createClassHeaderComments(Service service) {
+  private static List<CommentStatement> createClassHeaderComments(
+      Service service, TypeNode classType) {
+    // Pick the first pure unary rpc method, if no such method exists, then pick the first in the
+    // list.
     Optional<Method> methodOpt =
-        service.methods().isEmpty() ? Optional.empty() : Optional.of(service.methods().get(0));
+        service.methods().isEmpty()
+            ? Optional.empty()
+            : Optional.of(
+                service.methods().stream()
+                    .filter(m -> m.stream() == Stream.NONE && !m.hasLro() && !m.isPaged())
+                    .findFirst()
+                    .orElse(service.methods().stream().findFirst().get()));
     return SettingsCommentComposer.createClassHeaderComments(
-        getClientClassName(service.name()), service.defaultHost(), methodOpt);
+        getClientClassName(service.name()), service.defaultHost(), methodOpt, classType);
   }
 
   private static List<AnnotationNode> createClassAnnotations() {

src/main/java/com/google/api/generator/gapic/composer/ServiceStubSettingsClassComposer.java

@@ -78,6 +78,7 @@
 import com.google.api.generator.gapic.model.GapicServiceConfig;
 import com.google.api.generator.gapic.model.Message;
 import com.google.api.generator.gapic.model.Method;
+import com.google.api.generator.gapic.model.Method.Stream;
 import com.google.api.generator.gapic.model.Service;
 import com.google.api.generator.gapic.utils.JavaStyle;
 import com.google.common.base.Preconditions;
@@ -163,7 +164,7 @@ public GapicClass generate(
     ClassDefinition classDef =
         ClassDefinition.builder()
             .setPackageString(pakkage)
-            .setHeaderCommentStatements(createClassHeaderComments(service))
+            .setHeaderCommentStatements(createClassHeaderComments(service, types.get(className)))
             .setAnnotations(createClassAnnotations())
             .setScope(ScopeNode.PUBLIC)
             .setName(className)
@@ -187,11 +188,20 @@ private static List<AnnotationNode> createClassAnnotations() {
             .build());
   }
 
-  private static List<CommentStatement> createClassHeaderComments(Service service) {
+  private static List<CommentStatement> createClassHeaderComments(
+      Service service, TypeNode classType) {
+    // Pick the first pure unary rpc method, if no such method exists, then pick the first in the
+    // list.
     Optional<Method> methodOpt =
-        service.methods().isEmpty() ? Optional.empty() : Optional.of(service.methods().get(0));
+        service.methods().isEmpty()
+            ? Optional.empty()
+            : Optional.of(
+                service.methods().stream()
+                    .filter(m -> m.stream() == Stream.NONE && !m.hasLro() && !m.isPaged())
+                    .findFirst()
+                    .orElse(service.methods().stream().findFirst().get()));
     return SettingsCommentComposer.createClassHeaderComments(
-        String.format(STUB_PATTERN, service.name()), service.defaultHost(), methodOpt);
+        String.format(STUB_PATTERN, service.name()), service.defaultHost(), methodOpt, classType);
   }
 
   private static TypeNode createExtendsType(Service service, Map<String, TypeNode> types) {

src/main/java/com/google/api/generator/gapic/composer/SettingsCommentComposer.java

@@ -17,6 +17,7 @@
 import com.google.api.generator.engine.ast.CommentStatement;
 import com.google.api.generator.engine.ast.JavaDocComment;
 import com.google.api.generator.engine.ast.LineComment;
+import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.gapic.model.Method;
 import com.google.api.generator.gapic.utils.JavaStyle;
 import com.google.common.base.Preconditions;
@@ -28,6 +29,8 @@
 class SettingsCommentComposer {
   private static final String COLON = ":";
 
+  private static final String CLIENT_CLASS_NAME_PATTERN = "%sClient";
+  private static final String STUB_PATTERN = "%sStub";
   private static final String BUILDER_CLASS_DOC_PATTERN = "Builder for %s.";
   private static final String CALL_SETTINGS_METHOD_DOC_PATTERN =
       "Returns the object with the settings used for calls to %s.";
@@ -102,7 +105,10 @@ static CommentStatement createCallSettingsBuilderGetterComment(String javaMethod
   }
 
   static List<CommentStatement> createClassHeaderComments(
-      String configuredClassName, String defaultHost, Optional<Method> methodOpt) {
+      String configuredClassName,
+      String defaultHost,
+      Optional<Method> methodOpt,
+      TypeNode classType) {
     // Split default address and port.
     int colonIndex = defaultHost.indexOf(COLON);
     Preconditions.checkState(
@@ -127,12 +133,16 @@ static List<CommentStatement> createClassHeaderComments(
             .addParagraph(CLASS_HEADER_BUILDER_DESCRIPTION);
 
     if (methodOpt.isPresent()) {
+      String sampleCode =
+          SettingsSampleCodeComposer.composeSettingClassHeaderSampleCode(
+              methodOpt.get(), classType);
       javaDocCommentBuilder =
-          javaDocCommentBuilder.addParagraph(
-              String.format(
-                  CLASS_HEADER_SAMPLE_CODE_PATTERN,
-                  JavaStyle.toLowerCamelCase(methodOpt.get().name())));
-      // TODO(summerji): Add sample code here.
+          javaDocCommentBuilder
+              .addParagraph(
+                  String.format(
+                      CLASS_HEADER_SAMPLE_CODE_PATTERN,
+                      JavaStyle.toLowerCamelCase(methodOpt.get().name())))
+              .addSampleCode(sampleCode);
     }
 
     return Arrays.asList(

src/main/java/com/google/api/generator/gapic/composer/SettingsSampleCodeComposer.java

@@ -0,0 +1,163 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.api.generator.gapic.composer;
+
+import com.google.api.generator.engine.ast.AssignmentExpr;
+import com.google.api.generator.engine.ast.ConcreteReference;
+import com.google.api.generator.engine.ast.Expr;
+import com.google.api.generator.engine.ast.ExprStatement;
+import com.google.api.generator.engine.ast.MethodInvocationExpr;
+import com.google.api.generator.engine.ast.PrimitiveValue;
+import com.google.api.generator.engine.ast.Statement;
+import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.engine.ast.ValueExpr;
+import com.google.api.generator.engine.ast.VaporReference;
+import com.google.api.generator.engine.ast.Variable;
+import com.google.api.generator.engine.ast.VariableExpr;
+import com.google.api.generator.engine.writer.JavaWriterVisitor;
+import com.google.api.generator.gapic.composer.samplecode.SampleCodeJavaFormatter;
+import com.google.api.generator.gapic.model.Method;
+import com.google.api.generator.gapic.utils.JavaStyle;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public final class SettingsSampleCodeComposer {
+  // TODO(summerji): Add unit tests
+
+  private static final String BUILDER_NAME_PATTERN = "%sBuilder";
+  private static final String STUB = "Stub";
+  private static final String EMPTY_STRING = "";
+
+  public static String composeSettingClassHeaderSampleCode(Method method, TypeNode classType) {
+    // Initialize services settingsBuilder with newBuilder()
+    // e.g. FoobarSettings.Builder foobarSettingsBuilder = FoobarSettings.newBuilder();
+    String className = classType.reference().name();
+    TypeNode builderType =
+        TypeNode.withReference(
+            VaporReference.builder()
+                .setEnclosingClassNames(classType.reference().name())
+                .setName("Builder")
+                .setPakkage(classType.reference().pakkage())
+                .build());
+    Variable builderVar =
+        Variable.builder()
+            .setName(getClassSettingsBuilderName(className))
+            .setType(builderType)
+            .build();
+    VariableExpr localSettingsVarExpr = VariableExpr.withVariable(builderVar);
+    Expr settingsBuilderExpr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(classType)
+            .setMethodName("newBuilder")
+            .setReturnType(builderType)
+            .build();
+    Expr initLocalSettingsExpr =
+        AssignmentExpr.builder()
+            .setVariableExpr(localSettingsVarExpr.toBuilder().setIsDecl(true).build())
+            .setValueExpr(settingsBuilderExpr)
+            .build();
+
+    // Builder with set value method
+    // e.g
+    // foobarSettingBuilder.fooSetting().setRetrySettings(echoSettingsBuilder.echoSettings().getRetrySettings().toBuilder().setTotalTimeout(Duration.ofSeconds(30)).build());
+    MethodInvocationExpr retrySettingsMethodExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(localSettingsVarExpr)
+            .setMethodName(JavaStyle.toLowerCamelCase(String.format("%sSettings", method.name())))
+            .setReturnType(method.outputType())
+            .build();
+    MethodInvocationExpr timeoutArExpr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(
+                TypeNode.withReference(ConcreteReference.withClazz(Duration.class)))
+            .setMethodName("ofSeconds")
+            .setArguments(
+                ValueExpr.withValue(
+                    PrimitiveValue.builder().setType(TypeNode.INT).setValue("30").build()))
+            .build();
+    MethodInvocationExpr timeoutBuilderMethodExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(
+                MethodInvocationExpr.builder()
+                    .setExprReferenceExpr(
+                        MethodInvocationExpr.builder()
+                            .setExprReferenceExpr(retrySettingsMethodExpr)
+                            .setMethodName("getRetrySettings")
+                            .build())
+                    .setMethodName("toBuilder")
+                    .build())
+            .setMethodName("setTotalTimeout")
+            .setArguments(Arrays.asList(timeoutArExpr))
+            .build();
+    MethodInvocationExpr retrySettingsArgExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(timeoutBuilderMethodExpr)
+            .setMethodName("build")
+            .build();
+    MethodInvocationExpr settingBuilderMethodExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(retrySettingsMethodExpr)
+            .setMethodName("setRetrySettings")
+            .setArguments(Arrays.asList(retrySettingsArgExpr))
+            .build();
+
+    // Initialize clientSetting with builder() method.
+    // e.g: Foobar<Stub>Settings foobarSettings = foobarSettingsBuilder.build();
+    VariableExpr settingsVarExpr =
+        VariableExpr.withVariable(
+            Variable.builder()
+                .setType(classType)
+                .setName(getServiceSettingsName(className))
+                .build());
+    AssignmentExpr settingBuildAssignmentExpr =
+        AssignmentExpr.builder()
+            .setVariableExpr(settingsVarExpr.toBuilder().setIsDecl(true).build())
+            .setValueExpr(
+                MethodInvocationExpr.builder()
+                    .setExprReferenceExpr(localSettingsVarExpr)
+                    .setMethodName("build")
+                    .setReturnType(classType)
+                    .build())
+            .build();
+
+    List<Statement> statements =
+        Arrays.asList(initLocalSettingsExpr, settingBuilderMethodExpr, settingBuildAssignmentExpr)
+            .stream()
+            .map(e -> ExprStatement.withExpr(e))
+            .collect(Collectors.toList());
+    return SampleCodeJavaFormatter.format(writeStatements(statements));
+  }
+
+  private static String getServiceSettingsName(String className) {
+    return JavaStyle.toLowerCamelCase(className).replace(STUB, EMPTY_STRING);
+  }
+
+  private static String getClassSettingsBuilderName(String className) {
+    return JavaStyle.toLowerCamelCase(
+            String.format(BUILDER_NAME_PATTERN, JavaStyle.toLowerCamelCase(className)))
+        .replace(STUB, EMPTY_STRING);
+  }
+
+  // TODO(summerji): Refactor to use writeSampleCode method after PR#499 merged.
+  private static String writeStatements(List<Statement> statements) {
+    JavaWriterVisitor visitor = new JavaWriterVisitor();
+    for (Statement statement : statements) {
+      statement.accept(visitor);
+    }
+    return visitor.write();
+  }
+}

src/main/java/com/google/api/generator/gapic/composer/samplecode/BUILD.bazel

@@ -13,6 +13,10 @@ java_library(
         ":samplecode_files",
     ],
     deps = [
+        "//src/main/java/com/google/api/generator/engine/ast",
+        "//src/main/java/com/google/api/generator/engine/writer",
+        "//src/main/java/com/google/api/generator/gapic/model",
+        "//src/main/java/com/google/api/generator/gapic/utils",
         "@google_java_format_all_deps//jar",
     ],
 )

src/test/java/com/google/api/generator/gapic/composer/BUILD.bazel

@@ -31,6 +31,7 @@ TEST_DEPS = [
     "//src/main/java/com/google/api/generator/gapic/composer",
     "//src/test/java/com/google/api/generator/test/framework:asserts",
     "//src/test/java/com/google/api/generator/test/framework:utils",
+    "//src/main/java/com/google/api/generator/gapic/composer/samplecode",
     "//src/main/java/com/google/api/generator/gapic/model",
     "//src/main/java/com/google/api/generator/gapic/protoparser",
     "//src/test/java/com/google/api/generator/gapic/testdata:showcase_java_proto",

src/test/java/com/google/api/generator/gapic/composer/goldens/EchoSettings.golden

@@ -39,6 +39,20 @@ import javax.annotation.Generated;
  * build() is called, the tree of builders is called to create the complete settings object.
  *
  * <p>For example, to set the total timeout of echo to 30 seconds:
+ *
+ * <pre>{@code
+ * EchoSettings.Builder echoSettingsBuilder = EchoSettings.newBuilder();
+ * echoSettingsBuilder
+ *     .echoSettings()
+ *     .setRetrySettings(
+ *         echoSettingsBuilder
+ *             .echoSettings()
+ *             .getRetrySettings()
+ *             .toBuilder()
+ *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .build());
+ * EchoSettings echoSettings = echoSettingsBuilder.build();
+ * }</pre>
  */
 @Generated("by gapic-generator-java")
 public class EchoSettings extends ClientSettings<EchoSettings> {

src/test/java/com/google/api/generator/gapic/composer/goldens/EchoStubSettings.golden

@@ -67,6 +67,20 @@ import org.threeten.bp.Duration;
  * build() is called, the tree of builders is called to create the complete settings object.
  *
  * <p>For example, to set the total timeout of echo to 30 seconds:
+ *
+ * <pre>{@code
+ * EchoStubSettings.Builder echoSettingsBuilder = EchoStubSettings.newBuilder();
+ * echoSettingsBuilder
+ *     .echoSettings()
+ *     .setRetrySettings(
+ *         echoSettingsBuilder
+ *             .echoSettings()
+ *             .getRetrySettings()
+ *             .toBuilder()
+ *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .build());
+ * EchoStubSettings echoSettings = echoSettingsBuilder.build();
+ * }</pre>
  */
 @BetaApi
 @Generated("by gapic-generator-java")

src/test/java/com/google/api/generator/gapic/composer/goldens/LoggingServiceV2StubSettings.golden

@@ -64,6 +64,21 @@ import org.threeten.bp.Duration;
  * build() is called, the tree of builders is called to create the complete settings object.
  *
  * <p>For example, to set the total timeout of deleteLog to 30 seconds:
+ *
+ * <pre>{@code
+ * LoggingServiceV2StubSettings.Builder loggingServiceV2SettingsBuilder =
+ *     LoggingServiceV2StubSettings.newBuilder();
+ * loggingServiceV2SettingsBuilder
+ *     .deleteLogSettings()
+ *     .setRetrySettings(
+ *         loggingServiceV2SettingsBuilder
+ *             .deleteLogSettings()
+ *             .getRetrySettings()
+ *             .toBuilder()
+ *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .build());
+ * LoggingServiceV2StubSettings loggingServiceV2Settings = loggingServiceV2SettingsBuilder.build();
+ * }</pre>
  */
 @BetaApi
 @Generated("by gapic-generator-java")