程序包 org.beetl.core.util

类 SparseLongArray

java.lang.Object
org.beetl.core.util.SparseLongArray
所有已实现的接口:
Cloneable
public class SparseLongArray extends Object implements Cloneable
SparseLongArray 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 long 数组 SparseLongArrays map integers to longs. Unlike a normal array of longs, there can be gaps in the indices. It is intended to be more memory efficient than using a HashMap to map Integers to Longs, 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
    SparseLongArray()
    Creates a new SparseLongArray containing no mappings.
    SparseLongArray(int initialCapacity)
    Creates a new SparseLongArray 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, long 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.
    SparseLongArray
    clone()
     
    void
    delete(int key)
    Removes the mapping from the specified key, if there was any.
    long
    get(int key)
    Gets the long mapped from the specified key, or 0 if no such mapping has been made.
    long
    get(int key, long valueIfKeyNotFound)
    Gets the long 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(long 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 SparseLongArray stores.
    void
    put(int key, long 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
    removeAtRange(int index, int size)
     
    int
    size()
    Returns the number of key-value mappings that this SparseIntArray currently stores.
    String
    toString()
    long
    valueAt(int index)
    Given an index in the range 0...size()-1, returns the value from the indexth key-value mapping that this SparseLongArray 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

    • SparseLongArray

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

    • SparseLongArray

      public SparseLongArray(int initialCapacity)
      Creates a new SparseLongArray 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 SparseLongArray clone()
      覆盖:
      clone 在类中 Object

    • get

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

    • get

      public long get(int key, long valueIfKeyNotFound)
      Gets the long 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.

    • removeAtRange

      public void removeAtRange(int index, int size)
      参数:
      index - Index to begin at
      size - Number of mappings to remove

      For indices outside of the range 0...size()-1, the behavior is undefined.

    • removeAt

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

    • put

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

    • 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(long 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, long 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.

    • toString

      public String toString()

      This implementation composes a string by iterating over its mappings.

      覆盖:
      toString 在类中 Object