Module datarush.analytics
Package com.pervasive.datarush.analytics.arm

Class ItemSet

java.lang.Object
com.pervasive.datarush.analytics.arm.ItemSet
All Implemented Interfaces:
Serializable
public class ItemSet extends Object implements Serializable
A representation of a set of items with their support (frequency) within a data set. Items are represented by int values. It is assumed that each item has a distinct integer identifier.

The necessary methods are implemented allowing instances of this class to be used within the standard utility library (i.e. HashMap ...).

See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    ItemSet(int itemID)
    Construct an item set with a single item.
    ItemSet(int[] itemIDs)
    Construct an item set from the given items.
    ItemSet(int[] itemIDs, int length)
    Create an item set from the list of items specifying how many from the list to use.
    ItemSet(int[] itemsLHS, int[] itemsRHS)
    Combine the two sets of items into one set.
    ItemSet(int[] itemIDs, long support, double supportPct)
    Construct an item set from the given items.
    ItemSet(int itemID, int[] itemIDs)
    Combine the given singular item and a list of items into a single item set.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    calculateSupportPct(long transactionTotal)
    Given the number of transactions in a DB compute the support percent for this item set.
    boolean
    equals(Object o)
     
    int[]
    getItemIDs()
    Get the item identifiers contained in this item list.
    long
    getSupport()
    Get the current support value.
    double
    getSupportPct()
    Get the support percentage value.
    int
    hashCode()
     
    void
    incrementSupport()
    Increment the support value.
    static Comparator<ItemSet>
    newSetSizeComparator()
    Create a new Comparator that compares item sets and allows sorting by item set size and support.
    boolean
    represents(int[] items)
    Returns whether the given list of items matches the list of items within this item set.
    void
    setSupport(long support)
    Set the support value.
    int
    size()
    Return the size of this item set.
    String
    toString()
     

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • ItemSet

      public ItemSet(int itemID)
      Construct an item set with a single item.
      Parameters:
      itemID - item identifier

    • ItemSet

      public ItemSet(int[] itemIDs)
      Construct an item set from the given items. Assume ownership of the array.
      Parameters:
      itemIDs - items within the item set

    • ItemSet

      public ItemSet(int[] itemIDs, long support, double supportPct)
      Construct an item set from the given items. Assume ownership of the array. Use the given support values for initial values.
      Parameters:
      itemIDs - items within the item set
      support - the initial support value
      supportPct - the initial support percentage value

    • ItemSet

      public ItemSet(int itemID, int[] itemIDs)
      Combine the given singular item and a list of items into a single item set.
      Parameters:
      itemID - the singular item
      itemIDs - a list of items

    • ItemSet

      public ItemSet(int[] itemsLHS, int[] itemsRHS)
      Combine the two sets of items into one set.
      Parameters:
      itemsLHS - a list of item identifiers
      itemsRHS - a list of item identifiers

    • ItemSet

      public ItemSet(int[] itemIDs, int length)
      Create an item set from the list of items specifying how many from the list to use.
      Parameters:
      itemIDs - the item identifiers
      length - the number of items to include

  • Method Details

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • represents

      public boolean represents(int[] items)
      Returns whether the given list of items matches the list of items within this item set.
      Parameters:
      items - item identifiers
      Returns:
      true if all items match, false otherwise

    • size

      public int size()
      Return the size of this item set.
      Returns:
      the size of the item set

    • getItemIDs

      public int[] getItemIDs()
      Get the item identifiers contained in this item list.
      Returns:
      list of item identifiers

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • calculateSupportPct

      public void calculateSupportPct(long transactionTotal)
      Given the number of transactions in a DB compute the support percent for this item set.
      Parameters:
      transactionTotal - total number of transactions

    • getSupportPct

      public double getSupportPct()
      Get the support percentage value.
      Returns:
      support percentage (support / transaction count)

    • incrementSupport

      public void incrementSupport()
      Increment the support value.

    • getSupport

      public long getSupport()
      Get the current support value.
      Returns:
      support value

    • setSupport

      public void setSupport(long support)
      Set the support value.
      Parameters:
      support - support value to set

    • newSetSizeComparator

      public static Comparator<ItemSet> newSetSizeComparator()
      Create a new Comparator that compares item sets and allows sorting by item set size and support.
      Returns:
      a new Comparator instance