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Data Sketches Core

There is a newer version: 0.6.0

/*
 * Copyright 2015-16, Yahoo! Inc.
 * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
 */

package com.yahoo.sketches.tuple;

import com.yahoo.memory.Memory;

/**
 * Convenient static methods to instantiate generic tuple sketches.
 */
public final class Sketches {

  /**
   * @param  Type of Summary
   * @return an empty instance of Sketch
   */
  public static  Sketch createEmptySketch() {
    return new CompactSketch(null, null, Long.MAX_VALUE, true);
  }

  /**
   * Instantiate Sketch from a given Memory
   * @param  Type of Summary
   * @param mem Memory object representing a Sketch
   * @param deserializer instance of SummaryDeserializer
   * @return Sketch created from its Memory representation
   */
  public static  Sketch heapifySketch(final Memory mem,
      final SummaryDeserializer deserializer) {
    final SerializerDeserializer.SketchType sketchType = SerializerDeserializer.getSketchType(mem);
    if (sketchType == SerializerDeserializer.SketchType.QuickSelectSketch) {
      return new QuickSelectSketch(mem, deserializer, null);
    }
    return new CompactSketch(mem, deserializer);
  }

  /**
   * Instantiate UpdatableSketch from a given Memory
   * @param  Type of update value
   * @param  Type of Summary
   * @param mem Memory object representing a Sketch
   * @param deserializer instance of SummaryDeserializer
   * @param summaryFactory instance of SummaryFactory
   * @return Sketch created from its Memory representation
   */
  public static > UpdatableSketch heapifyUpdatableSketch(final Memory mem,
          final SummaryDeserializer deserializer, final SummaryFactory summaryFactory) {
    return new UpdatableSketch(mem, deserializer, summaryFactory);
  }

}