/*

  * 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 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 primitive values reduce operation

  *

  * @param <S> Primitive Writable type, which has its type ops

  */

 public class CollectPrimitiveReduceOperation<S>

     extends KryoWrappedReduceOperation<S, WArrayList<S>> {

   /**

    * Type ops if available, or null

    */

   private PrimitiveTypeOps<S> typeOps;

   /** For reflection only */

   public CollectPrimitiveReduceOperation() {

   }

   public CollectPrimitiveReduceOperation(PrimitiveTypeOps<S> typeOps) {

     this.typeOps = typeOps;

   }

   @Override

   public WArrayList<S> createValue() {

     return createList();

   }

   @Override

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

     reduceInto.addW(value);

   }

   @Override

   public void reduceMerge(final WArrayList<S> reduceInto,

       WArrayList<S> toReduce) {

     ResettableIterator<S> iterator = toReduce.fastIteratorW();

     while (iterator.hasNext()) {

       reduceInto.addW(iterator.next());

     }

   }

   public WArrayList<S> createList() {

     return typeOps.createArrayList();

   }

   @Override

   public void write(DataOutput out) throws IOException {

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

   }

   @Override

   public void readFields(DataInput in) throws IOException {

     typeOps = TypeOpsUtils.getPrimitiveTypeOps(

         WritableUtils.<S>readClass(in));

   }

 }