content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you 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 org.apache.calcite.avatica.remote;
  
  import org.apache.calcite.avatica.AvaticaUtils;
  
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.HttpURLConnection;
  import java.net.URL;
  
  /**
   * A common class to invoke HTTP requests against the Avatica server agnostic of the data being
   * sent and received across the wire.
   */
  public class AvaticaHttpClientImpl implements AvaticaHttpClient {
    protected final URL url;
  
    public AvaticaHttpClientImpl(URL url) {
      this.url = url;
    }
  
    public byte[] send(byte[] request) {
      // TODO back-off policy?
      while (true) {
        try {
          final HttpURLConnection connection = openConnection();
          connection.setRequestMethod("POST");
          connection.setDoInput(true);
          connection.setDoOutput(true);
          try (DataOutputStream wr = new DataOutputStream(connection.getOutputStream())) {
            wr.write(request);
            wr.flush();
            wr.close();
          }
          final int responseCode = connection.getResponseCode();
          final InputStream inputStream;
          if (responseCode == HttpURLConnection.HTTP_UNAVAILABLE) {
            // Could be sitting behind a load-balancer, try again.
            continue;
          } else if (responseCode != HttpURLConnection.HTTP_OK) {
            inputStream = connection.getErrorStream();
            if (inputStream == null) {
              // HTTP Transport exception that resulted in no content coming back
              throw new RuntimeException("Failed to read data from the server: HTTP/" + responseCode);
            }
          } else {
            inputStream = connection.getInputStream();
          }
          return AvaticaUtils.readFullyToBytes(inputStream);
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
    }
  
    HttpURLConnection openConnection() throws IOException {
      return (HttpURLConnection) url.openConnection();
    }
  }
  
  // End AvaticaHttpClientImpl.java
  