/*
    * 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.giraph.writable.kryo.serializers;
  
  import java.util.Collections;
  import java.util.List;
  
  import com.esotericsoftware.kryo.Kryo;
  import com.esotericsoftware.kryo.Serializer;
  import com.esotericsoftware.kryo.io.Input;
  import com.esotericsoftware.kryo.io.Output;
  
  /**
   * Special serializer for Collections.nCopies
   *
   * @param <T> Element type
   */
  public class CollectionsNCopiesSerializer<T> extends Serializer<List<T>> {
    @Override
    public void write(Kryo kryo, Output output, List<T> object) {
      output.writeInt(object.size(), true);
      if (object.size() > 0) {
        kryo.writeClassAndObject(output, object.get(0));
      }
    }
  
    @Override
    public List<T> read(Kryo kryo, Input input, Class<List<T>> type) {
      int size = input.readInt(true);
      if (size > 0) {
        T object = (T) kryo.readClassAndObject(input);
        return Collections.nCopies(size, object);
      } else {
        return Collections.emptyList();
      }
    }
  }