/*

  * 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.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.List;

 import org.apache.giraph.reducers.impl.KryoWrappedReduceOperation;

 import org.apache.giraph.types.ops.PrimitiveTypeOps;

 import org.apache.giraph.types.ops.TypeOpsUtils;

 import org.apache.giraph.types.ops.collections.ResettableIterator;

 import org.apache.giraph.types.ops.collections.array.WArrayList;

 import org.apache.giraph.utils.WritableUtils;

 /**

  * Collect tuples of primitive values reduce operation

  */

 public class CollectTuplesOfPrimitivesReduceOperation

     extends KryoWrappedReduceOperation<List<Object>, List<WArrayList>> {

   /**

    * Type ops if available, or null

    */

   private List<PrimitiveTypeOps> typeOpsList;

   /** For reflection only */

   public CollectTuplesOfPrimitivesReduceOperation() {

   }

   public CollectTuplesOfPrimitivesReduceOperation(

       List<PrimitiveTypeOps> typeOpsList) {

     this.typeOpsList = typeOpsList;

   }

   @Override

   public List<WArrayList> createValue() {

     List<WArrayList> ret = new ArrayList<>(typeOpsList.size());

     for (PrimitiveTypeOps typeOps : typeOpsList) {

       ret.add(typeOps.createArrayList());

     }

     return ret;

   }

   @Override

   public void reduce(List<WArrayList> reduceInto, List<Object> value) {

     for (int i = 0; i < reduceInto.size(); i++) {

       reduceInto.get(i).addW(value.get(i));

     }

   }

   @Override

   public void reduceMerge(final List<WArrayList> reduceInto,

       List<WArrayList> toReduce) {

     for (int i = 0; i < reduceInto.size(); i++) {

       ResettableIterator iterator = toReduce.get(i).fastIteratorW();

       while (iterator.hasNext()) {

         reduceInto.get(i).addW(iterator.next());

       }

     }

   }

   @Override

   public void write(DataOutput out) throws IOException {

     out.writeInt(typeOpsList.size());

     for (PrimitiveTypeOps typeOps : typeOpsList) {

       WritableUtils.writeClass(typeOps.getTypeClass(), out);

     }

   }

   @Override

   public void readFields(DataInput in) throws IOException {

     int size = in.readInt();

     typeOpsList = new ArrayList<>(size);

     for (int i = 0; i < size; i++) {

       typeOpsList.add(TypeOpsUtils.getPrimitiveTypeOps(

           WritableUtils.readClass(in)));

     }

   }

 }