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.asterix.external.input.stream;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.ServerSocket;
  import java.net.Socket;
  
  import org.apache.asterix.external.api.AsterixInputStream;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.util.CleanupUtils;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  public class SocketServerInputStream extends AsterixInputStream {
      private static final Logger LOGGER = LogManager.getLogger();
      private ServerSocket server;
      private Socket socket;
      private InputStream connectionStream;
  
      public SocketServerInputStream(ServerSocket server) {
          this.server = server;
          socket = new Socket();
          connectionStream = new InputStream() {
              @Override
              public int read() throws IOException {
                  return -1;
              }
          };
      }
  
      @Override
      public int read() throws IOException {
          int read = connectionStream.read();
          while (read < 0) {
              accept();
              read = connectionStream.read();
          }
          return read;
      }
  
      @Override
      public int read(byte b[]) throws IOException {
          return read(b, 0, b.length);
      }
  
      @Override
      public int read(byte b[], int off, int len) throws IOException {
          if (server == null) {
              return -1;
          }
          int read = -1;
          try {
              if (connectionStream.available() < 1) {
                  controller.flush();
              }
              read = connectionStream.read(b, off, len);
          } catch (IOException e) {
              // exception is expected when no connection available
              LOGGER.info("Exhausted all pending connections. Waiting for new ones to come.");
              read = -1;
          }
          while (read < 0) {
              if (!accept()) {
                  return -1;
              }
              try {
                  read = connectionStream.read(b, off, len);
              } catch (IOException e) {
                  e.printStackTrace();
                  read = -1;
              }
          }
          return read;
      }
  
      @Override
      public long skip(long n) throws IOException {
          return 0;
      }
  
      @Override
      public int available() throws IOException {
          return 1;
      }
  
      @Override
      public synchronized void close() throws IOException {
          Throwable failure = CleanupUtils.close(connectionStream, null);
          connectionStream = null;
          failure = CleanupUtils.close(socket, failure);
          socket = null;
          failure = CleanupUtils.close(server, failure);
          server = null;
          if (failure != null) {
              throw HyracksDataException.create(failure);
          }
      }
  
      private boolean accept() throws IOException {
          try {
              connectionStream.close();
              connectionStream = null;
              socket.close();
              socket = null;
              socket = server.accept();
              connectionStream = socket.getInputStream();
              return true;
          } catch (Exception e) {
              close();
              return false;
          }
      }
  
      @Override
      public boolean stop() throws Exception {
          close();
          return true;
      }
  
      @Override
      public boolean handleException(Throwable th) {
          if (th instanceof RuntimeException) {
              //Log runtime exception
              //TODO Should we continue anyway?
              LOGGER.error("Encountered an unexpected error", th);
          }
          try {
              return accept();
          } catch (IOException e) {
              LOGGER.warn("Failed accepting more connections", e);
              return false;
          }
      }
  }
  