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/*
 * 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.quantiles;

import com.yahoo.memory.Memory;
import com.yahoo.memory.WritableMemory;

/**
 * For building a new DoublesSketch Union operation.
 *
 * @author Lee Rhodes
 */
public class DoublesUnionBuilder {
  private int bMaxK = PreambleUtil.DEFAULT_K;

  /**
   * Constructor for a new DoublesUnionBuilder. The default configuration is
   * 
   * k: 128. This produces a normalized rank error of about 1.7%
   * Memory: null
   * 
   */
  public DoublesUnionBuilder() {}

  /**
   * Sets the parameter masK that determines the maximum size of the sketch that
   * results from a union and its accuracy.
   * @param maxK determines the accuracy and size of the union and is a maximum value.
   * The effective k can be smaller due to unions with smaller k sketches.
   * It is recommended that maxK be a power of 2 to enable unioning of sketches with
   * different values of k.
   * @return this builder
   */
  public DoublesUnionBuilder setMaxK(final int maxK) {
    Util.checkK(maxK);
    bMaxK = maxK;
    return this;
  }

  /**
   * Gets the current configured value of maxK
   * @return the current configured value of maxK
   */
  public int getMaxK() {
    return bMaxK;
  }

  /**
   * Returns a new empty Union object with the current configuration of this Builder.
   * @return a Union object
   */
  public DoublesUnion build() {
    return DoublesUnionImpl.heapInstance(bMaxK);
  }

  /**
   * Returns a new empty Union object with the current configuration of this Builder
   * and the specified backing destination Memory store.
   * @param dstMem the destination memory
   * @return a Union object
   */
  public DoublesUnion build(final WritableMemory dstMem) {
    return DoublesUnionImpl.directInstance(bMaxK, dstMem);
  }

  /**
   * Returns a Heap Union object that has been initialized with the data from the given sketch.
   * @param sketch A DoublesSketch to be used as a source of data only and will not be modified.
   * @return a DoublesUnion object
   * @deprecated moved to DoublesUnion
   */
  @Deprecated
  public static DoublesUnion heapify(final DoublesSketch sketch) {
    return DoublesUnionImpl.heapifyInstance(sketch);
  }

  /**
   * Returns a Heap Union object that has been initialized with the data from the given memory
   * image of a sketch.
   *
   * @param srcMem A memory image of a DoublesSketch to be used as a source of data,
   * but will not be modified.
   * @return a Union object
   * @deprecated moved to DoublesUnion
   */
  @Deprecated
  public static DoublesUnion heapify(final Memory srcMem) {
    return DoublesUnionImpl.heapifyInstance(srcMem);
  }

  /**
   * Returns a read-only Union object that wraps off-heap data of the given memory image of
   * a sketch. The data structures of the Union remain off-heap.
   *
   * @param mem A memory region to be used as the data structure for the sketch
   * and will be modified.
   * @return a Union object
   * @deprecated moved to DoublesUnion
   */
  @Deprecated
  public static DoublesUnion wrap(final Memory mem) {
    return DoublesUnionImplR.wrapInstance(mem);
  }

  /**
   * Returns an updatable Union object that wraps off-heap data of the given memory image of
   * a sketch. The data structures of the Union remain off-heap.
   *
   * @param mem A memory region to be used as the data structure for the sketch
   * and will be modified.
   * @return a Union object
   * @deprecated moved to DoublesUnion
   */
  @Deprecated
  public static DoublesUnion wrap(final WritableMemory mem) {
    return DoublesUnionImpl.wrapInstance(mem);
  }

}