程序包 org.beetl.core.util

类 SparseIntArray

java.lang.Object
org.beetl.core.util.SparseIntArray
所有已实现的接口:
Cloneable
public class SparseIntArray extends Object implements Cloneable
SparseIntArray 的内部是通过两个数组对数据进行存储的， key 为 int 数组， value 为 int 数组 SparseIntArrays map integers to integers. Unlike a normal array of integers, there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Integers, both because it avoids auto-boxing keys and values and its data structure doesn't rely on an extra entry object for each mapping.

Note that this container keeps its mappings in an array data structure, using a binary search to find keys. The implementation is not intended to be appropriate for data structures that may contain large numbers of items. It is generally slower than a traditional HashMap, since lookups require a binary search and adds and removes require inserting and deleting entries in the array. For containers holding up to hundreds of items, the performance difference is not significant, less than 50%.

It is possible to iterate over the items in this container using keyAt(int) and valueAt(int). Iterating over the keys using keyAt(int) with ascending values of the index will return the keys in ascending order, or the values corresponding to the keys in ascending order in the case of valueAt(int).

  • 构造器概要

    构造器
    构造器
    说明
    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.

  • 方法概要

    修饰符和类型
    方法
    说明
    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.
    void
    clear()
    Removes all key-value mappings from this SparseIntArray.
    SparseIntArray
    clone()
     
    int[]
    copyKeys()
    Provides a copy of keys.
    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
    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.
    void
    setValueAt(int index, int value)
    Directly set the value at a particular index.
    int
    size()
    Returns the number of key-value mappings that this SparseIntArray currently stores.
    String
    toString()
    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.

    从类继承的方法 java.lang.Object

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

  • 构造器详细资料

    • 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. If you supply an initial capacity of 0, the sparse array will be initialized with a light-weight representation not requiring any additional array allocations.

  • 方法详细资料

    • clone

      public SparseIntArray clone()
      覆盖:
      clone 在类中 Object

    • 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.

    • 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.

      The keys corresponding to indices in ascending order are guaranteed to be in ascending order, e.g., keyAt(0) will return the smallest key and keyAt(size()-1) will return the largest key.

    • 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.

      The values corresponding to indices in ascending order are guaranteed to be associated with keys in ascending order, e.g., valueAt(0) will return the value associated with the smallest key and valueAt(size()-1) will return the value associated with the largest key.

    • setValueAt

      public void setValueAt(int index, int value)
      Directly set the value at a particular index.

    • 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.

    • copyKeys

      public int[] copyKeys()
      Provides a copy of keys.

    • toString

      public String toString()

      This implementation composes a string by iterating over its mappings.

      覆盖:
      toString 在类中 Object