org.htmlunit.cyberneko.util

Class FastHashMap<K,V>

java.lang.Object

org.htmlunit.cyberneko.util.FastHashMap<K,V>

Type Parameters:

K - the type of the key

V - the type of the value

All Implemented Interfaces:

Serializable

public class FastHashMap<K,V>
extends Object
implements Serializable

Simple hash map implementation taken from here https://github.com/mikvor/hashmapTest/blob/master/src/main/java/map/objobj/ObjObjMap.java No concrete license specified at the source. The project is public domain. Not thread-safe! Null support was removed.

Since:

3.10.0

Author:

René Schwietzke

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
FastHashMap()
FastHashMap(int size, float fillFactor)

Method Summary

Modifier and Type	Method and Description
static int	arraySize(int expected, float f) Returns the least power of two smaller than or equal to 230 and larger than or equal to Math.ceil( expected / f ).
void	clear() Clears the map, reuses the data structure by clearing it out.
V	get(K key)
List<K>	keys()
static long	nextPowerOfTwo(long x) Return the least power of two greater than or equal to the specified value.
V	put(K key, V value)
V	remove(K key)
int	size()
List<V>	values()

Methods inherited from class java.lang.Object

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

Constructor Detail

FastHashMap

public FastHashMap()

FastHashMap

public FastHashMap(int size,
                   float fillFactor)

Method Detail

get

public V get(K key)

put

public V put(K key,
             V value)

remove

public V remove(K key)

size

public int size()

keys

public List<K> keys()

Returns:

a list of all keys

values

public List<V> values()

Returns:

a list of all values

clear

public void clear()

Clears the map, reuses the data structure by clearing it out. It won't shrink the underlying array!

nextPowerOfTwo

public static long nextPowerOfTwo(long x)

Return the least power of two greater than or equal to the specified value.

Note that this function will return 1 when the argument is 0.

Parameters:

x - a long integer smaller than or equal to 2⁶².

Returns:

the least power of two greater than or equal to the specified value.

arraySize

public static int arraySize(int expected,
                            float f)

Returns the least power of two smaller than or equal to 2³⁰ and larger than or equal to Math.ceil( expected / f ).

Parameters:

expected - the expected number of elements in a hash table.

f - the load factor.

Returns:

the minimum possible size for a backing array.

Throws:

IllegalArgumentException - if the necessary size is larger than 2³⁰.