DIREGAPIC LRO implementation without annotations

WORKSPACE

@@ -32,7 +32,7 @@ jvm_maven_import_external(
 # gapic-generator-java dependencies to match the order in googleapis repository,
 # which in its turn, prioritizes actual generated clients runtime dependencies
 # over the generator dependencies.
-_gax_java_version = "1.65.1"
+_gax_java_version = "2.2.0"
 
 http_archive(
     name = "com_google_api_gax_java",

src/main/java/com/google/api/generator/gapic/composer/rest/HttpJsonServiceCallableFactoryClassComposer.java

@@ -16,14 +16,27 @@
 
 import com.google.api.gax.core.BackgroundResource;
 import com.google.api.gax.httpjson.ApiMessage;
+import com.google.api.gax.httpjson.HttpJsonCallableFactory;
+import com.google.api.gax.httpjson.HttpJsonOperationSnapshotCallable;
+import com.google.api.gax.rpc.OperationCallable;
+import com.google.api.gax.rpc.UnaryCallable;
 import com.google.api.generator.engine.ast.AnnotationNode;
+import com.google.api.generator.engine.ast.AssignmentExpr;
 import com.google.api.generator.engine.ast.ConcreteReference;
+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.NewObjectExpr;
+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.gapic.composer.common.AbstractServiceCallableFactoryClassComposer;
 import com.google.api.generator.gapic.composer.store.TypeStore;
 import com.google.api.generator.gapic.model.Service;
+import com.google.longrunning.Operation;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -90,6 +103,7 @@ protected MethodDefinition createOperationCallableMethod(TypeStore typeStore) {
             "The surface for long-running operations is not stable yet and may change in the"
                 + " future.");
 
+    // Generate generic method without the body
     MethodDefinition method =
         createGenericCallableMethod(
             typeStore,
@@ -104,6 +118,116 @@ protected MethodDefinition createOperationCallableMethod(TypeStore typeStore) {
                 .map(n -> (Object) n)
                 .collect(Collectors.toList()),
             Arrays.asList(betaAnnotation));
-    return method.toBuilder().setReturnExpr(ValueExpr.createNullExpr()).build();
+
+    List<Statement> createOperationCallableBody = new ArrayList<Statement>(2);
+
+    List<VariableExpr> arguments = method.arguments();
+
+    // Generate innerCallable
+    VariableExpr innerCallableVarExpr =
+        VariableExpr.builder()
+            .setVariable(
+                Variable.builder()
+                    .setName("innerCallable")
+                    .setType(
+                        TypeNode.withReference(ConcreteReference.withClazz(UnaryCallable.class)))
+                    .build())
+            .setTemplateObjects(Arrays.asList(requestTemplateName, methodVariantName))
+            .build();
+    MethodInvocationExpr getInitialCallSettingsExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(VariableExpr.withVariable(arguments.get(1).variable()))
+            .setMethodName("getInitialCallSettings")
+            .build();
+    MethodInvocationExpr createBaseUnaryCallableExpr =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(
+                TypeNode.withReference(ConcreteReference.withClazz(HttpJsonCallableFactory.class)))
+            .setMethodName("createBaseUnaryCallable")
+            .setArguments(
+                VariableExpr.withVariable(arguments.get(0).variable()),
+                getInitialCallSettingsExpr,
+                VariableExpr.withVariable(arguments.get(2).variable()))
+            .setReturnType(TypeNode.withReference(ConcreteReference.withClazz(UnaryCallable.class)))
+            .build();
+    AssignmentExpr innerCallableAssignExpr =
+        AssignmentExpr.builder()
+            .setVariableExpr(innerCallableVarExpr.toBuilder().setIsDecl(true).build())
+            .setValueExpr(createBaseUnaryCallableExpr)
+            .build();
+    createOperationCallableBody.add(ExprStatement.withExpr(innerCallableAssignExpr));
+
+    // Generate initialCallable
+    VariableExpr initialCallableVarExpr =
+        VariableExpr.builder()
+            .setVariable(
+                Variable.builder()
+                    .setName("initialCallable")
+                    .setType(
+                        TypeNode.withReference(ConcreteReference.withClazz(UnaryCallable.class)))
+                    .build())
+            .setTemplateObjects(Arrays.asList(requestTemplateName, methodVariantName))
+            .build();
+    MethodInvocationExpr getMethodDescriptorExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(VariableExpr.withVariable(arguments.get(0).variable()))
+            .setMethodName("getMethodDescriptor")
+            .build();
+    MethodInvocationExpr getOperationSnapshotFactoryExpr =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(getMethodDescriptorExpr)
+            .setMethodName("getOperationSnapshotFactory")
+            .build();
+    // This is a temporary solution
+    VaporReference requestT =
+        VaporReference.builder()
+            .setName("RequestT")
+            .setPakkage("com.google.cloud.compute.v1.stub")
+            .build();
+    TypeNode operationSnapshotCallableType =
+        TypeNode.withReference(
+            ConcreteReference.builder()
+                .setClazz(HttpJsonOperationSnapshotCallable.class)
+                .setGenerics(requestT, ConcreteReference.withClazz(Operation.class))
+                .build());
+    NewObjectExpr initialCallableObject =
+        NewObjectExpr.builder()
+            .setType(operationSnapshotCallableType)
+            .setIsGeneric(true)
+            .setArguments(innerCallableVarExpr, getOperationSnapshotFactoryExpr)
+            .build();
+    AssignmentExpr initialCallableAssignExpr =
+        AssignmentExpr.builder()
+            .setVariableExpr(initialCallableVarExpr.toBuilder().setIsDecl(true).build())
+            .setValueExpr(initialCallableObject)
+            .build();
+    createOperationCallableBody.add(ExprStatement.withExpr(initialCallableAssignExpr));
+
+    // Generate return statement
+    MethodInvocationExpr longRunningClient =
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(VariableExpr.withVariable(arguments.get(3).variable()))
+            .setMethodName("longRunningClient")
+            .build();
+    MethodInvocationExpr createOperationCallable =
+        MethodInvocationExpr.builder()
+            .setStaticReferenceType(
+                TypeNode.withReference(ConcreteReference.withClazz(HttpJsonCallableFactory.class)))
+            .setMethodName("createOperationCallable")
+            .setArguments(
+                VariableExpr.withVariable(arguments.get(1).variable()),
+                VariableExpr.withVariable(arguments.get(2).variable()),
+                longRunningClient,
+                initialCallableVarExpr)
+            .setReturnType(
+                TypeNode.withReference(ConcreteReference.withClazz(OperationCallable.class)))
+            .build();
+
+    // Add body and return statement to method
+    return method
+        .toBuilder()
+        .setBody(createOperationCallableBody)
+        .setReturnExpr(createOperationCallable)
+        .build();
   }
 }