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.spark.serializer;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  
  import scala.reflect.ClassTag;
  
  import org.apache.spark.annotation.Private;
  import org.apache.spark.unsafe.Platform;
  
  /**
   * Unfortunately, we need a serializer instance in order to construct a DiskBlockObjectWriter.
   * Our shuffle write path doesn't actually use this serializer (since we end up calling the
   * `write() OutputStream methods), but DiskBlockObjectWriter still calls some methods on it. To work
   * around this, we pass a dummy no-op serializer.
   */
  @Private
  public final class DummySerializerInstance extends SerializerInstance {
  
    public static final DummySerializerInstance INSTANCE = new DummySerializerInstance();
  
    private DummySerializerInstance() { }
  
    @Override
    public SerializationStream serializeStream(final OutputStream s) {
      return new SerializationStream() {
        @Override
        public void flush() {
          // Need to implement this because DiskObjectWriter uses it to flush the compression stream
          try {
            s.flush();
          } catch (IOException e) {
            Platform.throwException(e);
          }
        }
  
        @Override
        public <T> SerializationStream writeObject(T t, ClassTag<T> ev1) {
          throw new UnsupportedOperationException();
        }
  
        @Override
        public void close() {
          // Need to implement this because DiskObjectWriter uses it to close the compression stream
          try {
            s.close();
          } catch (IOException e) {
            Platform.throwException(e);
          }
        }
      };
    }
  
    @Override
    public <T> ByteBuffer serialize(T t, ClassTag<T> ev1) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public DeserializationStream deserializeStream(InputStream s) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public <T> T deserialize(ByteBuffer bytes, ClassLoader loader, ClassTag<T> ev1) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public <T> T deserialize(ByteBuffer bytes, ClassTag<T> ev1) {
      throw new UnsupportedOperationException();
    }
  }
  