feat: Enable REST transport for most of Java and Go clients

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceClient.java

@@ -17,13 +17,13 @@
 package com.google.cloud.documentai.v1;
 
 import com.google.api.gax.core.BackgroundResource;
+import com.google.api.gax.httpjson.longrunning.OperationsClient;
 import com.google.api.gax.longrunning.OperationFuture;
 import com.google.api.gax.rpc.OperationCallable;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1.stub.DocumentProcessorServiceStub;
 import com.google.cloud.documentai.v1.stub.DocumentProcessorServiceStubSettings;
 import com.google.longrunning.Operation;
-import com.google.longrunning.OperationsClient;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
@@ -99,13 +99,29 @@
  *     DocumentProcessorServiceClient.create(documentProcessorServiceSettings);
  * }</pre>
  *
+ * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending and receiving requests over
+ * the wire:
+ *
+ * <pre>{@code
+ * // This snippet has been automatically generated for illustrative purposes only.
+ * // It may require modifications to work in your environment.
+ * DocumentProcessorServiceSettings documentProcessorServiceSettings =
+ *     DocumentProcessorServiceSettings.newBuilder()
+ *         .setTransportChannelProvider(
+ *             DocumentProcessorServiceSettings.defaultHttpJsonTransportProviderBuilder().build())
+ *         .build();
+ * DocumentProcessorServiceClient documentProcessorServiceClient =
+ *     DocumentProcessorServiceClient.create(documentProcessorServiceSettings);
+ * }</pre>
+ *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
 @Generated("by gapic-generator-java")
 public class DocumentProcessorServiceClient implements BackgroundResource {
   private final DocumentProcessorServiceSettings settings;
   private final DocumentProcessorServiceStub stub;
-  private final OperationsClient operationsClient;
+  private final OperationsClient httpJsonOperationsClient;
+  private final com.google.longrunning.OperationsClient operationsClient;
 
   /** Constructs an instance of DocumentProcessorServiceClient with default settings. */
   public static final DocumentProcessorServiceClient create() throws IOException {
@@ -139,13 +155,17 @@ protected DocumentProcessorServiceClient(DocumentProcessorServiceSettings settin
       throws IOException {
     this.settings = settings;
     this.stub = ((DocumentProcessorServiceStubSettings) settings.getStubSettings()).createStub();
-    this.operationsClient = OperationsClient.create(this.stub.getOperationsStub());
+    this.operationsClient =
+        com.google.longrunning.OperationsClient.create(this.stub.getOperationsStub());
+    this.httpJsonOperationsClient = OperationsClient.create(this.stub.getHttpJsonOperationsStub());
   }
 
   protected DocumentProcessorServiceClient(DocumentProcessorServiceStub stub) {
     this.settings = null;
     this.stub = stub;
-    this.operationsClient = OperationsClient.create(this.stub.getOperationsStub());
+    this.operationsClient =
+        com.google.longrunning.OperationsClient.create(this.stub.getOperationsStub());
+    this.httpJsonOperationsClient = OperationsClient.create(this.stub.getHttpJsonOperationsStub());
   }
 
   public final DocumentProcessorServiceSettings getSettings() {
@@ -160,10 +180,18 @@ public DocumentProcessorServiceStub getStub() {
    * Returns the OperationsClient that can be used to query the status of a long-running operation
    * returned by another API method call.
    */
-  public final OperationsClient getOperationsClient() {
+  public final com.google.longrunning.OperationsClient getOperationsClient() {
     return operationsClient;
   }
 
+  /**
+   * Returns the OperationsClient that can be used to query the status of a long-running operation
+   * returned by another API method call.
+   */
+  public final OperationsClient getHttpJsonOperationsClient() {
+    return httpJsonOperationsClient;
+  }
+
   // AUTO-GENERATED DOCUMENTATION AND METHOD.
   /**
    * Processes a single document.

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java

@@ -21,6 +21,7 @@
 import com.google.api.gax.core.GoogleCredentialsProvider;
 import com.google.api.gax.core.InstantiatingExecutorProvider;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
+import com.google.api.gax.httpjson.InstantiatingHttpJsonChannelProvider;
 import com.google.api.gax.rpc.ApiClientHeaderProvider;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.ClientSettings;
@@ -128,11 +129,18 @@ public static GoogleCredentialsProvider.Builder defaultCredentialsProviderBuilde
     return DocumentProcessorServiceStubSettings.defaultCredentialsProviderBuilder();
   }
 
-  /** Returns a builder for the default ChannelProvider for this service. */
+  /** Returns a builder for the default gRPC ChannelProvider for this service. */
   public static InstantiatingGrpcChannelProvider.Builder defaultGrpcTransportProviderBuilder() {
     return DocumentProcessorServiceStubSettings.defaultGrpcTransportProviderBuilder();
   }
 
+  /** Returns a builder for the default REST ChannelProvider for this service. */
+  @BetaApi
+  public static InstantiatingHttpJsonChannelProvider.Builder
+      defaultHttpJsonTransportProviderBuilder() {
+    return DocumentProcessorServiceStubSettings.defaultHttpJsonTransportProviderBuilder();
+  }
+
   public static TransportChannelProvider defaultTransportChannelProvider() {
     return DocumentProcessorServiceStubSettings.defaultTransportChannelProvider();
   }
@@ -142,11 +150,17 @@ public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuil
     return DocumentProcessorServiceStubSettings.defaultApiClientHeaderProviderBuilder();
   }
 
-  /** Returns a new builder for this class. */
+  /** Returns a new gRPC builder for this class. */
   public static Builder newBuilder() {
     return Builder.createDefault();
   }
 
+  /** Returns a new REST builder for this class. */
+  @BetaApi
+  public static Builder newHttpJsonBuilder() {
+    return Builder.createHttpJsonDefault();
+  }
+
   /** Returns a new builder for this class. */
   public static Builder newBuilder(ClientContext clientContext) {
     return new Builder(clientContext);
@@ -185,6 +199,11 @@ private static Builder createDefault() {
       return new Builder(DocumentProcessorServiceStubSettings.newBuilder());
     }
 
+    @BetaApi
+    private static Builder createHttpJsonDefault() {
+      return new Builder(DocumentProcessorServiceStubSettings.newHttpJsonBuilder());
+    }
+
     public DocumentProcessorServiceStubSettings.Builder getStubSettingsBuilder() {
       return ((DocumentProcessorServiceStubSettings.Builder) getStubSettings());
     }

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStub.java

@@ -41,7 +41,11 @@
 public abstract class DocumentProcessorServiceStub implements BackgroundResource {
 
   public OperationsStub getOperationsStub() {
-    throw new UnsupportedOperationException("Not implemented: getOperationsStub()");
+    return null;
+  }
+
+  public com.google.api.gax.httpjson.longrunning.stub.OperationsStub getHttpJsonOperationsStub() {
+    return null;
   }
 
   public UnaryCallable<ProcessRequest, ProcessResponse> processDocumentCallable() {

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java

@@ -25,6 +25,9 @@
 import com.google.api.gax.grpc.GrpcTransportChannel;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.api.gax.grpc.ProtoOperationTransformers;
+import com.google.api.gax.httpjson.GaxHttpJsonProperties;
+import com.google.api.gax.httpjson.HttpJsonTransportChannel;
+import com.google.api.gax.httpjson.InstantiatingHttpJsonChannelProvider;
 import com.google.api.gax.longrunning.OperationSnapshot;
 import com.google.api.gax.longrunning.OperationTimedPollAlgorithm;
 import com.google.api.gax.retrying.RetrySettings;
@@ -139,6 +142,11 @@ public DocumentProcessorServiceStub createStub() throws IOException {
         .equals(GrpcTransportChannel.getGrpcTransportName())) {
       return GrpcDocumentProcessorServiceStub.create(this);
     }
+    if (getTransportChannelProvider()
+        .getTransportName()
+        .equals(HttpJsonTransportChannel.getHttpJsonTransportName())) {
+      return HttpJsonDocumentProcessorServiceStub.create(this);
+    }
     throw new UnsupportedOperationException(
         String.format(
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
@@ -171,30 +179,56 @@ public static GoogleCredentialsProvider.Builder defaultCredentialsProviderBuilde
         .setUseJwtAccessWithScope(true);
   }
 
-  /** Returns a builder for the default ChannelProvider for this service. */
+  /** Returns a builder for the default gRPC ChannelProvider for this service. */
   public static InstantiatingGrpcChannelProvider.Builder defaultGrpcTransportProviderBuilder() {
     return InstantiatingGrpcChannelProvider.newBuilder()
         .setMaxInboundMessageSize(Integer.MAX_VALUE);
   }
 
+  /** Returns a builder for the default REST ChannelProvider for this service. */
+  @BetaApi
+  public static InstantiatingHttpJsonChannelProvider.Builder
+      defaultHttpJsonTransportProviderBuilder() {
+    return InstantiatingHttpJsonChannelProvider.newBuilder();
+  }
+
   public static TransportChannelProvider defaultTransportChannelProvider() {
     return defaultGrpcTransportProviderBuilder().build();
   }
 
   @BetaApi("The surface for customizing headers is not stable yet and may change in the future.")
-  public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuilder() {
+  public static ApiClientHeaderProvider.Builder defaultGrpcApiClientHeaderProviderBuilder() {
     return ApiClientHeaderProvider.newBuilder()
         .setGeneratedLibToken(
             "gapic", GaxProperties.getLibraryVersion(DocumentProcessorServiceStubSettings.class))
         .setTransportToken(
             GaxGrpcProperties.getGrpcTokenName(), GaxGrpcProperties.getGrpcVersion());
   }
 
-  /** Returns a new builder for this class. */
+  @BetaApi("The surface for customizing headers is not stable yet and may change in the future.")
+  public static ApiClientHeaderProvider.Builder defaultHttpJsonApiClientHeaderProviderBuilder() {
+    return ApiClientHeaderProvider.newBuilder()
+        .setGeneratedLibToken(
+            "gapic", GaxProperties.getLibraryVersion(DocumentProcessorServiceStubSettings.class))
+        .setTransportToken(
+            GaxHttpJsonProperties.getHttpJsonTokenName(),
+            GaxHttpJsonProperties.getHttpJsonVersion());
+  }
+
+  public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuilder() {
+    return DocumentProcessorServiceStubSettings.defaultGrpcApiClientHeaderProviderBuilder();
+  }
+
+  /** Returns a new gRPC builder for this class. */
   public static Builder newBuilder() {
     return Builder.createDefault();
   }
 
+  /** Returns a new REST builder for this class. */
+  public static Builder newHttpJsonBuilder() {
+    return Builder.createHttpJsonDefault();
+  }
+
   /** Returns a new builder for this class. */
   public static Builder newBuilder(ClientContext clientContext) {
     return new Builder(clientContext);
@@ -312,6 +346,19 @@ private static Builder createDefault() {
       return initDefaults(builder);
     }
 
+    private static Builder createHttpJsonDefault() {
+      Builder builder = new Builder(((ClientContext) null));
+
+      builder.setTransportChannelProvider(defaultHttpJsonTransportProviderBuilder().build());
+      builder.setCredentialsProvider(defaultCredentialsProviderBuilder().build());
+      builder.setInternalHeaderProvider(defaultHttpJsonApiClientHeaderProviderBuilder().build());
+      builder.setEndpoint(getDefaultEndpoint());
+      builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
+      builder.setSwitchToMtlsEndpointAllowed(true);
+
+      return initDefaults(builder);
+    }
+
     private static Builder initDefaults(Builder builder) {
       builder
           .processDocumentSettings()

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/HttpJsonDocumentProcessorServiceCallableFactory.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2022 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
+ *
+ *      https://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.cloud.documentai.v1.stub;
+
+import com.google.api.core.BetaApi;
+import com.google.api.gax.httpjson.HttpJsonCallSettings;
+import com.google.api.gax.httpjson.HttpJsonCallableFactory;
+import com.google.api.gax.httpjson.HttpJsonOperationSnapshotCallable;
+import com.google.api.gax.httpjson.HttpJsonStubCallableFactory;
+import com.google.api.gax.httpjson.longrunning.stub.OperationsStub;
+import com.google.api.gax.rpc.BatchingCallSettings;
+import com.google.api.gax.rpc.ClientContext;
+import com.google.api.gax.rpc.OperationCallSettings;
+import com.google.api.gax.rpc.OperationCallable;
+import com.google.api.gax.rpc.PagedCallSettings;
+import com.google.api.gax.rpc.ServerStreamingCallSettings;
+import com.google.api.gax.rpc.ServerStreamingCallable;
+import com.google.api.gax.rpc.UnaryCallSettings;
+import com.google.api.gax.rpc.UnaryCallable;
+import com.google.longrunning.Operation;
+import javax.annotation.Generated;
+
+// AUTO-GENERATED DOCUMENTATION AND CLASS.
+/**
+ * REST callable factory implementation for the DocumentProcessorService service API.
+ *
+ * <p>This class is for advanced usage.
+ */
+@Generated("by gapic-generator-java")
+@BetaApi
+public class HttpJsonDocumentProcessorServiceCallableFactory
+    implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
+
+  @Override
+  public <RequestT, ResponseT> UnaryCallable<RequestT, ResponseT> createUnaryCallable(
+      HttpJsonCallSettings<RequestT, ResponseT> httpJsonCallSettings,
+      UnaryCallSettings<RequestT, ResponseT> callSettings,
+      ClientContext clientContext) {
+    return HttpJsonCallableFactory.createUnaryCallable(
+        httpJsonCallSettings, callSettings, clientContext);
+  }
+
+  @Override
+  public <RequestT, ResponseT, PagedListResponseT>
+      UnaryCallable<RequestT, PagedListResponseT> createPagedCallable(
+          HttpJsonCallSettings<RequestT, ResponseT> httpJsonCallSettings,
+          PagedCallSettings<RequestT, ResponseT, PagedListResponseT> callSettings,
+          ClientContext clientContext) {
+    return HttpJsonCallableFactory.createPagedCallable(
+        httpJsonCallSettings, callSettings, clientContext);
+  }
+
+  @Override
+  public <RequestT, ResponseT> UnaryCallable<RequestT, ResponseT> createBatchingCallable(
+      HttpJsonCallSettings<RequestT, ResponseT> httpJsonCallSettings,
+      BatchingCallSettings<RequestT, ResponseT> callSettings,
+      ClientContext clientContext) {
+    return HttpJsonCallableFactory.createBatchingCallable(
+        httpJsonCallSettings, callSettings, clientContext);
+  }
+
+  @BetaApi(
+      "The surface for long-running operations is not stable yet and may change in the future.")
+  @Override
+  public <RequestT, ResponseT, MetadataT>
+      OperationCallable<RequestT, ResponseT, MetadataT> createOperationCallable(
+          HttpJsonCallSettings<RequestT, Operation> httpJsonCallSettings,
+          OperationCallSettings<RequestT, ResponseT, MetadataT> callSettings,
+          ClientContext clientContext,
+          OperationsStub operationsStub) {
+    UnaryCallable<RequestT, Operation> innerCallable =
+        HttpJsonCallableFactory.createBaseUnaryCallable(
+            httpJsonCallSettings, callSettings.getInitialCallSettings(), clientContext);
+    HttpJsonOperationSnapshotCallable<RequestT, Operation> initialCallable =
+        new HttpJsonOperationSnapshotCallable<RequestT, Operation>(
+            innerCallable,
+            httpJsonCallSettings.getMethodDescriptor().getOperationSnapshotFactory());
+    return HttpJsonCallableFactory.createOperationCallable(
+        callSettings, clientContext, operationsStub.longRunningClient(), initialCallable);
+  }
+
+  @Override
+  public <RequestT, ResponseT>
+      ServerStreamingCallable<RequestT, ResponseT> createServerStreamingCallable(
+          HttpJsonCallSettings<RequestT, ResponseT> httpJsonCallSettings,
+          ServerStreamingCallSettings<RequestT, ResponseT> callSettings,
+          ClientContext clientContext) {
+    return HttpJsonCallableFactory.createServerStreamingCallable(
+        httpJsonCallSettings, callSettings, clientContext);
+  }
+}