docs(sample): Update parallel append sample to use StreamWriterV2 (#883)

* Support building a BigQueryWriteClient within the StreamWriterV2.

* feat: Support building a BigQueryWriteClient within the StreamWriterV2

* docs(sample): Update parallel append sample to use StreamWriterV2

samples/snippets/src/main/java/com/example/bigquerystorage/ParallelWriteCommittedStream.java

@@ -20,21 +20,29 @@
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutureCallback;
 import com.google.api.core.ApiFutures;
+import com.google.cloud.bigquery.storage.v1beta2.AppendRowsRequest;
 import com.google.cloud.bigquery.storage.v1beta2.AppendRowsResponse;
+import com.google.cloud.bigquery.storage.v1beta2.BQTableSchemaToProtoDescriptor;
 import com.google.cloud.bigquery.storage.v1beta2.BigQueryWriteClient;
 import com.google.cloud.bigquery.storage.v1beta2.CreateWriteStreamRequest;
-import com.google.cloud.bigquery.storage.v1beta2.JsonStreamWriter;
+import com.google.cloud.bigquery.storage.v1beta2.JsonToProtoMessage;
+import com.google.cloud.bigquery.storage.v1beta2.ProtoRows;
+import com.google.cloud.bigquery.storage.v1beta2.ProtoSchema;
+import com.google.cloud.bigquery.storage.v1beta2.ProtoSchemaConverter;
+import com.google.cloud.bigquery.storage.v1beta2.StreamWriterV2;
 import com.google.cloud.bigquery.storage.v1beta2.TableName;
 import com.google.cloud.bigquery.storage.v1beta2.WriteStream;
 import com.google.common.util.concurrent.MoreExecutors;
+import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.DescriptorValidationException;
+import com.google.protobuf.Int64Value;
+import com.google.protobuf.Message;
 import java.io.IOException;
 import java.time.Duration;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.GuardedBy;
-import org.json.JSONArray;
 import org.json.JSONObject;
 
 public class ParallelWriteCommittedStream {
@@ -151,20 +159,20 @@ private void writeToStream(
       lastMetricsSuccessCount = 0;
       lastMetricsFailureCount = 0;
     }
-    // Use the JSON stream writer to send records in JSON format.
-    // For more information about JsonStreamWriter, see:
-    // https://googleapis.dev/java/google-cloud-bigquerystorage/latest/com/google/cloud/bigquery/storage/v1beta2/JsonStreamWriter.html
-    try (JsonStreamWriter writer =
-        JsonStreamWriter.newBuilder(writeStream.getName(), writeStream.getTableSchema(), client)
-            .build()) {
+    Descriptor descriptor =
+        BQTableSchemaToProtoDescriptor.convertBQTableSchemaToProtoDescriptor(
+            writeStream.getTableSchema());
+    ProtoSchema protoSchema = ProtoSchemaConverter.convert(descriptor);
+    try (StreamWriterV2 writer = StreamWriterV2.newBuilder(writeStream.getName()).build()) {
       while (System.currentTimeMillis() < deadlineMillis) {
         synchronized (this) {
           if (error != null) {
             // Stop writing once we get an error.
             throw error;
           }
         }
-        ApiFuture<AppendRowsResponse> future = writer.append(createPayload(), -1);
+        ApiFuture<AppendRowsResponse> future =
+            writer.append(createAppendRequest(writeStream.getName(), descriptor, protoSchema, -1));
         synchronized (this) {
           inflightCount++;
         }
@@ -189,17 +197,26 @@ private void waitForInflightToReachZero(Duration timeout) {
     throw new RuntimeException("Timeout waiting for inflight count to reach 0");
   }
 
-  private JSONArray createPayload() {
-    // Create a JSON object that is compatible with the table schema.
-    JSONArray jsonArr = new JSONArray();
+  private AppendRowsRequest createAppendRequest(
+      String streamName, Descriptor descriptor, ProtoSchema protoSchema, long offset) {
+    ProtoRows.Builder rowsBuilder = ProtoRows.newBuilder();
     for (int i = 0; i < BATCH_SIZE; i++) {
       byte[] payload = new byte[ROW_SIZE];
       ThreadLocalRandom.current().nextBytes(payload);
       JSONObject record = new JSONObject();
       record.put("col1", new String(payload));
-      jsonArr.put(record);
+      Message protoMessage = JsonToProtoMessage.convertJsonToProtoMessage(descriptor, record);
+      rowsBuilder.addSerializedRows(protoMessage.toByteString());
     }
-    return jsonArr;
+    AppendRowsRequest.ProtoData.Builder data = AppendRowsRequest.ProtoData.newBuilder();
+    data.setWriterSchema(protoSchema);
+    data.setRows(rowsBuilder.build());
+    AppendRowsRequest.Builder request = AppendRowsRequest.newBuilder().setProtoRows(data.build());
+    request.setWriteStream(streamName);
+    if (offset >= 0) {
+      request.setOffset(Int64Value.of(offset));
+    }
+    return request.build();
   }
 
   private void sleepIgnoringInterruption(Duration duration) {