/*
    * 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.block_app.reducers.collect;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.giraph.block_app.framework.api.CreateReducersApi;
  import org.apache.giraph.block_app.framework.piece.global_comm.BroadcastHandle;
  import org.apache.giraph.block_app.framework.piece.global_comm.array.BroadcastArrayHandle;
  import org.apache.giraph.master.MasterGlobalCommUsage;
  import org.apache.giraph.reducers.ReduceOperation;
  import org.apache.giraph.worker.WorkerBroadcastUsage;
  import org.apache.giraph.writable.kryo.KryoWritableWrapper;
  
  /**
   * ShardedReducerHandle where we keep a list of reduced values
   *
   * @param <S> Single value type
   */
  public class CollectShardedReducerHandle<S>
      extends ShardedReducerHandle<S, List<S>> {
    public CollectShardedReducerHandle(CreateReducersApi reduceApi) {
      register(reduceApi);
    }
  
    @Override
    public ReduceOperation<S, KryoWritableWrapper<List<S>>>
    createReduceOperation() {
      return new CollectReduceOperation<>();
    }
  
    @Override
    public List<S> createReduceResult(MasterGlobalCommUsage master) {
      int size = 0;
      for (int i = 0; i < REDUCER_COUNT; i++) {
        size += reducers.get(i).getReducedValue(master).get().size();
      }
      return createList(size);
    }
  
    public List<S> createList(int size) {
      return new ArrayList<S>(size);
    }
  
    @Override
    public BroadcastHandle<List<S>> createBroadcastHandle(
        BroadcastArrayHandle<KryoWritableWrapper<List<S>>> broadcasts) {
      return new CollectShardedBroadcastHandle(broadcasts);
    }
  
    /**
     * BroadcastHandle for CollectShardedReducerHandle
     */
    public class CollectShardedBroadcastHandle extends ShardedBroadcastHandle {
      public CollectShardedBroadcastHandle(
          BroadcastArrayHandle<KryoWritableWrapper<List<S>>> broadcasts) {
        super(broadcasts);
      }
  
      @Override
      public List<S> createBroadcastResult(WorkerBroadcastUsage worker) {
        int size = 0;
        for (int i = 0; i < REDUCER_COUNT; i++) {
          size += broadcasts.get(i).getBroadcast(worker).get().size();
        }
        return createList(size);
      }
    }
  }