content: /*
   * Tencent is pleased to support the open source community by making Angel available.
   *
   * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
   *
   * Licensed 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
   *
   * https://opensource.org/licenses/Apache-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 com.tencent.angel.graph.client.node2vec.getfuncs.pullpathtail;
  
  import com.tencent.angel.graph.client.node2vec.utils.Merge;
  import com.tencent.angel.graph.client.node2vec.utils.PathQueue;
  import com.tencent.angel.ml.matrix.psf.get.base.GetFunc;
  import com.tencent.angel.ml.matrix.psf.get.base.GetParam;
  import com.tencent.angel.ml.matrix.psf.get.base.GetResult;
  import com.tencent.angel.ml.matrix.psf.get.base.PartitionGetParam;
  import com.tencent.angel.ml.matrix.psf.get.base.PartitionGetResult;
  import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
  import java.util.ArrayList;
  import java.util.List;
  
  public class PullPathTail extends GetFunc {
  
    /**
     * Create a new DefaultGetFunc.
     *
     * @param param parameter of get udf
     */
    public PullPathTail(GetParam param) {
      super(param);
    }
  
    public PullPathTail() {
      super(null);
    }
  
    @Override
    public PartitionGetResult partitionGet(PartitionGetParam partParam) {
      PullPathTailPartitionParam pparam = (PullPathTailPartitionParam) partParam;
      int psPartitionId = pparam.getPartKey().getPartitionId();
  
      Long2ObjectOpenHashMap<long[]> result = new Long2ObjectOpenHashMap<>();
      PathQueue.popBatchTail(psPartitionId, pparam.getBatchSize(), result);
  
      return new PullPathTailPartitionResult(result);
    }
  
    @Override
    public GetResult merge(List<PartitionGetResult> partResults) {
      List<Long2ObjectOpenHashMap<long[]>> maps = new ArrayList<>(partResults.size());
  
      for (PartitionGetResult partResult : partResults) {
        if (partResult != null) {
          maps.add(((PullPathTailPartitionResult) partResult).getPartRestlt());
        }
      }
  
      return new PullPathTailResult(Merge.mergeHadhMap(maps));
    }
  }
  