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.spark.ml.tree.sketch;
  
  import java.io.Serializable;
  
  public abstract class QuantileSketch implements Serializable {
  
    protected long n; // total number of data items appeared
    protected long estimateN; // estimated total number of data items there will be,
    // if not -1, sufficient space will be allocated at once
  
    protected float minValue;
    protected float maxValue;
  
    public QuantileSketch(long estimateN) {
      this.estimateN = estimateN > 0 ? estimateN : -1L;
    }
  
    public QuantileSketch() {
      this(-1L);
    }
  
    public abstract void reset();
  
    public abstract void update(float value);
  
    public abstract void merge(QuantileSketch other);
  
    public abstract float getQuantile(float fraction);
  
    public abstract float[] getQuantiles(float[] fractions);
  
    public abstract float[] getQuantiles(int evenPartition);
  
    public boolean isEmpty() {
      return n == 0;
    }
  
    public long getN() {
      return n;
    }
  
    public long getEstimateN() {
      return estimateN;
    }
  
    public float getMinValue() {
      return minValue;
    }
  
    public float getMaxValue() {
      return maxValue;
    }
  }
  