Class QuantilesItemsUnion<T>

java.lang.Object
org.apache.datasketches.quantiles.QuantilesItemsUnion<T>
Type Parameters:
T - The sketch item data type.
public final class QuantilesItemsUnion<T> extends Object
The API for Union operations for generic QuantilesItemsSketches
Author:
Lee Rhodes, Alexander Saydakov

  • Method Details

    • getInstance

      public static <T> QuantilesItemsUnion<T> getInstance(Class<T> clazz, Comparator<? super T> comparator)
      Create an instance of QuantilesItemsUnion with the default k.
      Type Parameters:
      T - The sketch item data type.
      Parameters:
      clazz - The sketch class type.
      comparator - to compare items.
      Returns:
      a new instance of QuantilesItemsUnion

    • getInstance

      public static <T> QuantilesItemsUnion<T> getInstance(Class<T> clazz, int maxK, Comparator<? super T> comparator)
      Create an instance of QuantilesItemsUnion
      Type Parameters:
      T - The sketch item data type.
      Parameters:
      clazz - The sketch class type.
      maxK - determines the accuracy and size of the union and is a maximum. The effective k can be smaller due to unions with smaller k sketches. maxK must be a power of 2 to enable unioning of sketches with a different k.
      comparator - to compare items.
      Returns:
      an new instance of QuantilesItemsUnion

    • initializeWithMemorySegment

      public static <T> QuantilesItemsUnion<T> initializeWithMemorySegment(Class<T> clazz, MemorySegment srcSeg, Comparator<? super T> comparator, ArrayOfItemsSerDe<T> serDe)
      Initialize a new QuantilesItemsUnion with a heapified instance of an QuantilesItemsSketch from a MemorySegment.
      Type Parameters:
      T - The sketch data type.
      Parameters:
      clazz - The sketch class type.
      srcSeg - the given srcSeg, an image of an QuantilesItemsSketch. A reference to srcSeg will not be maintained internally.
      comparator - to compare items.
      serDe - an instance of ArrayOfItemsSerDe.
      Returns:
      an QuantilesItemsUnion initialized with a heapified QuantilesItemsSketch from a MemorySegment.

    • initialize

      public static <T> QuantilesItemsUnion<T> initialize(QuantilesItemsSketch<T> sketch)
      Initialize a new QuantilesItemsUnion with an instance of QuantilesItemsSketch
      Type Parameters:
      T - The sketch data type
      Parameters:
      sketch - an instance of QuantilesItemsSketch to initialize this union
      Returns:
      an initialized instance of QuantilesItemsUnion

    • union

      public void union(QuantilesItemsSketch<T> sketchIn)
      Iterative union operation, which means this method can be repeatedly called. Merges the given sketch into this union object. The given sketch is not modified. It is required that the ratio of the two K's be a power of 2. This is easily satisfied if each of the K's are already a power of 2. If the given sketch is null or empty it is ignored.

      It is required that the results of the union operation, which can be obtained at any time, is obtained from getResult().

      Parameters:
      sketchIn - the sketch to be merged into this one.

    • union

      public void union(MemorySegment srcSeg, ArrayOfItemsSerDe<T> serDe)
      Iterative union operation, which means this method can be repeatedly called. Merges the given MemorySegment image of a QuantilesItemsSketch into this union object. The given MemorySegment object is not modified and a link to it is not retained. It is required that the ratio of the two K's be a power of 2. This is easily satisfied if each of the K's are already a power of 2. If the given sketch is null or empty it is ignored.

      It is required that the results of the union operation, which can be obtained at any time, is obtained from getResult().

      Parameters:
      srcSeg - MemorySegment image of sketch to be merged
      serDe - an instance of ArrayOfItemsSerDe

    • update

      public void update(T dataItem)
      Update this union with the given dataItem.
      Parameters:
      dataItem - The given datum.

    • getResult

      public QuantilesItemsSketch<T> getResult()
      Gets the result of this Union operation as a copy of the internal state. This enables further union update operations on this state.
      Returns:
      the result of this Union operation

    • getResultAndReset

      public QuantilesItemsSketch<T> getResultAndReset()
      Gets the sketch result of this Union operation and resets this Union to the virgin state.
      Returns:
      the result of this Union operation and reset.

    • reset

      public void reset()
      Resets this Union to a virgin state. Keeps maxK, comparator and clazz

    • isEmpty

      public boolean isEmpty()
      Returns true if this union is empty
      Returns:
      true if this union is empty

    • getMaxK

      public int getMaxK()
      Returns the configured maxK of this Union.
      Returns:
      the configured maxK of this Union.

    • getEffectiveK

      public int getEffectiveK()
      Returns the effective k of this Union.
      Returns:
      the effective k of this Union.

    • toString

      public String toString()
      Returns summary information about the backing sketch.
      Overrides:
      toString in class Object

    • toString

      public String toString(boolean sketchSummary, boolean dataDetail)
      Returns summary information about the backing sketch. Used for debugging.
      Parameters:
      sketchSummary - if true includes sketch summary
      dataDetail - if true includes data detail
      Returns:
      summary information about the sketch.

    • toByteArray

      public byte[] toByteArray(ArrayOfItemsSerDe<T> serDe)
      Serialize this union to a byte array. Result is an QuantilesItemsSketch, serialized in an unordered, non-compact form. The resulting byte[] can be passed to getInstance for either a sketch or union.
      Parameters:
      serDe - an instance of ArrayOfItemsSerDe
      Returns:
      byte array of this union