feat: ExecutableSampleComposer

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

@@ -0,0 +1,53 @@
+// Copyright 2021 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.samplecode;
+
+import com.google.api.generator.engine.ast.AssignmentExpr;
+import com.google.api.generator.engine.ast.Statement;
+import java.util.List;
+
+public class ExecutableSample {
+  private final String samplePackage;
+  private final String sampleName;
+  private final List<AssignmentExpr> sampleVariableAssignments;
+  private final List<Statement> sampleBody;
+
+  public ExecutableSample(
+      String samplePackage,
+      String sampleName,
+      List<AssignmentExpr> sampleVariableAssignments,
+      List<Statement> sampleBody) {
+    this.samplePackage = samplePackage;
+    this.sampleName = sampleName;
+    this.sampleVariableAssignments = sampleVariableAssignments;
+    this.sampleBody = sampleBody;
+  }
+
+  public String getSamplePackage() {
+    return samplePackage;
+  }
+
+  public String getSampleName() {
+    return sampleName;
+  }
+
+  public List<AssignmentExpr> getSampleVariableAssignments() {
+    return sampleVariableAssignments;
+  }
+
+  public List<Statement> getSampleBody() {
+    return sampleBody;
+  }
+}

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

@@ -0,0 +1,140 @@
+// Copyright 2021 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.samplecode;
+
+import com.google.api.generator.engine.ast.AssignmentExpr;
+import com.google.api.generator.engine.ast.ClassDefinition;
+import com.google.api.generator.engine.ast.Expr;
+import com.google.api.generator.engine.ast.ExprStatement;
+import com.google.api.generator.engine.ast.MethodDefinition;
+import com.google.api.generator.engine.ast.MethodInvocationExpr;
+import com.google.api.generator.engine.ast.ScopeNode;
+import com.google.api.generator.engine.ast.Statement;
+import com.google.api.generator.engine.ast.TypeNode;
+import com.google.api.generator.engine.ast.Variable;
+import com.google.api.generator.engine.ast.VariableExpr;
+import com.google.api.generator.gapic.utils.JavaStyle;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class ExecutableSampleComposer {
+  public static String createExecutableSample(ExecutableSample executableSample) {
+    Preconditions.checkNotNull(executableSample);
+    String sampleMethodName = JavaStyle.toLowerCamelCase(executableSample.getSampleName());
+    return SampleCodeWriter.write(
+        composeExecutableSample(
+            executableSample.getSamplePackage(),
+            sampleMethodName,
+            executableSample.getSampleVariableAssignments(),
+            executableSample.getSampleBody()));
+  }
+
+  private static ClassDefinition composeExecutableSample(
+      String packageName,
+      String sampleMethodName,
+      List<AssignmentExpr> sampleVariableAssignments,
+      List<Statement> sampleBody) {
+    String sampleClassName = JavaStyle.toUpperCamelCase(sampleMethodName);
+    List<VariableExpr> sampleMethodArgs = composeSampleMethodArgs(sampleVariableAssignments);
+    MethodDefinition mainMethod =
+        composeMainMethod(
+            composeMainBody(
+                sampleVariableAssignments,
+                composeInvokeMethodStatement(sampleMethodName, sampleMethodArgs)));
+    MethodDefinition sampleMethod =
+        composeSampleMethod(sampleMethodName, sampleMethodArgs, sampleBody);
+    return composeSampleClass(packageName, sampleClassName, mainMethod, sampleMethod);
+  }
+
+  private static List<VariableExpr> composeSampleMethodArgs(
+      List<AssignmentExpr> sampleVariableAssignments) {
+    return sampleVariableAssignments.stream()
+        .map(v -> v.variableExpr().toBuilder().setIsDecl(true).build())
+        .collect(Collectors.toList());
+  }
+
+  private static Statement composeInvokeMethodStatement(
+      String sampleMethodName, List<VariableExpr> sampleMethodArgs) {
+    List<Expr> invokeArgs =
+        sampleMethodArgs.stream()
+            .map(arg -> arg.toBuilder().setIsDecl(false).build())
+            .collect(Collectors.toList());
+    return ExprStatement.withExpr(
+        MethodInvocationExpr.builder()
+            .setMethodName(sampleMethodName)
+            .setArguments(invokeArgs)
+            .build());
+  }
+
+  private static List<Statement> composeMainBody(
+      List<AssignmentExpr> sampleVariableAssignments, Statement invokeMethod) {
+    List<ExprStatement> setVariables =
+        sampleVariableAssignments.stream()
+            .map(var -> ExprStatement.withExpr(var))
+            .collect(Collectors.toList());
+    List<Statement> body = new ArrayList<>(setVariables);
+    body.add(invokeMethod);
+    return body;
+  }
+
+  private static ClassDefinition composeSampleClass(
+      String packageName,
+      String sampleClassName,
+      MethodDefinition mainMethod,
+      MethodDefinition sampleMethod) {
+    return ClassDefinition.builder()
+        .setScope(ScopeNode.PUBLIC)
+        .setPackageString(packageName)
+        .setName(sampleClassName)
+        .setMethods(ImmutableList.of(mainMethod, sampleMethod))
+        .build();
+  }
+
+  private static MethodDefinition composeMainMethod(List<Statement> mainBody) {
+    return MethodDefinition.builder()
+        .setScope(ScopeNode.PUBLIC)
+        .setIsStatic(true)
+        .setReturnType(TypeNode.VOID)
+        .setName("main")
+        .setArguments(
+            VariableExpr.builder()
+                .setVariable(
+                    Variable.builder().setType(TypeNode.STRING_ARRAY).setName("args").build())
+                .setIsDecl(true)
+                .build())
+        .setThrowsExceptions(Arrays.asList(TypeNode.withExceptionClazz(Exception.class)))
+        .setBody(mainBody)
+        .build();
+  }
+
+  private static MethodDefinition composeSampleMethod(
+      String sampleMethodName,
+      List<VariableExpr> sampleMethodArgs,
+      List<Statement> sampleMethodBody) {
+    return MethodDefinition.builder()
+        .setScope(ScopeNode.PUBLIC)
+        .setIsStatic(true)
+        .setReturnType(TypeNode.VOID)
+        .setName(sampleMethodName)
+        .setArguments(sampleMethodArgs)
+        .setThrowsExceptions(Arrays.asList(TypeNode.withExceptionClazz(Exception.class)))
+        .setBody(sampleMethodBody)
+        .build();
+  }
+}

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

@@ -14,6 +14,7 @@
 
 package com.google.api.generator.gapic.composer.samplecode;
 
+import com.google.api.generator.engine.ast.ClassDefinition;
 import com.google.api.generator.engine.ast.Statement;
 import com.google.api.generator.engine.writer.JavaWriterVisitor;
 import java.util.Arrays;
@@ -34,4 +35,10 @@ public static String write(List<Statement> statements) {
     // Escape character "@" in the markdown code block <pre>{@code...} tags.
     return formattedSampleCode.replaceAll("@", "{@literal @}");
   }
+
+  public static String write(ClassDefinition classDefinition) {
+    JavaWriterVisitor visitor = new JavaWriterVisitor();
+    classDefinition.accept(visitor);
+    return visitor.write();
+  }
 }

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

@@ -7,6 +7,7 @@ TESTS = [
     "SampleCodeWriterTest",
     "ServiceClientSampleCodeComposerTest",
     "SettingsSampleCodeComposerTest",
+    "ExecutableSampleComposerTest"
 ]
 
 filegroup(