Package org.jf.util

Class SparseIntArray

java.lang.Object
org.jf.util.SparseIntArray
public class SparseIntArray extends Object
SparseIntArrays map integers to integers. Unlike a normal array of integers, there can be gaps in the indices. It is intended to be more efficient than using a HashMap to map Integers to Integers.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private int[]
    mKeys
     
    private int
    mSize
     
    private int[]
    mValues
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    SparseIntArray()
    Creates a new SparseIntArray containing no mappings.
    SparseIntArray(int initialCapacity)
    Creates a new SparseIntArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    append(int key, int value)
    Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.
    private static int
    binarySearch(int[] a, int start, int len, int key)
     
    void
    clear()
    Removes all key-value mappings from this SparseIntArray.
    void
    delete(int key)
    Removes the mapping from the specified key, if there was any.
    int
    get(int key)
    Gets the int mapped from the specified key, or 0 if no such mapping has been made.
    int
    get(int key, int valueIfKeyNotFound)
    Gets the int mapped from the specified key, or the specified value if no such mapping has been made.
    int
    getClosestSmaller(int key)
    Gets the int mapped from the specified key, or if not present, the closest key that is less than the specified key.
    int
    indexOfKey(int key)
    Returns the index for which keyAt(int) would return the specified key, or a negative number if the specified key is not mapped.
    int
    indexOfValue(int value)
    Returns an index for which valueAt(int) would return the specified key, or a negative number if no keys map to the specified value.
    int
    keyAt(int index)
    Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this SparseIntArray stores.
    void
    put(int key, int value)
    Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.
    void
    removeAt(int index)
    Removes the mapping at the given index.
    int
    size()
    Returns the number of key-value mappings that this SparseIntArray currently stores.
    int
    valueAt(int index)
    Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this SparseIntArray stores.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • mKeys

      private int[] mKeys

    • mValues

      private int[] mValues

    • mSize

      private int mSize

  • Constructor Details

    • SparseIntArray

      public SparseIntArray()
      Creates a new SparseIntArray containing no mappings.

    • SparseIntArray

      public SparseIntArray(int initialCapacity)
      Creates a new SparseIntArray containing no mappings that will not require any additional memory allocation to store the specified number of mappings.

  • Method Details

    • get

      public int get(int key)
      Gets the int mapped from the specified key, or 0 if no such mapping has been made.

    • get

      public int get(int key, int valueIfKeyNotFound)
      Gets the int mapped from the specified key, or the specified value if no such mapping has been made.

    • getClosestSmaller

      public int getClosestSmaller(int key)
      Gets the int mapped from the specified key, or if not present, the closest key that is less than the specified key.

    • delete

      public void delete(int key)
      Removes the mapping from the specified key, if there was any.

    • removeAt

      public void removeAt(int index)
      Removes the mapping at the given index.

    • put

      public void put(int key, int value)
      Adds a mapping from the specified key to the specified value, replacing the previous mapping from the specified key if there was one.

    • size

      public int size()
      Returns the number of key-value mappings that this SparseIntArray currently stores.

    • keyAt

      public int keyAt(int index)
      Given an index in the range 0...size()-1, returns the key from the indexth key-value mapping that this SparseIntArray stores.

    • valueAt

      public int valueAt(int index)
      Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this SparseIntArray stores.

    • indexOfKey

      public int indexOfKey(int key)
      Returns the index for which keyAt(int) would return the specified key, or a negative number if the specified key is not mapped.

    • indexOfValue

      public int indexOfValue(int value)
      Returns an index for which valueAt(int) would return the specified key, or a negative number if no keys map to the specified value. Beware that this is a linear search, unlike lookups by key, and that multiple keys can map to the same value and this will find only one of them.

    • clear

      public void clear()
      Removes all key-value mappings from this SparseIntArray.

    • append

      public void append(int key, int value)
      Puts a key/value pair into the array, optimizing for the case where the key is greater than all existing keys in the array.

    • binarySearch

      private static int binarySearch(int[] a, int start, int len, int key)