it.unimi.dsi.fastutil.objects

Class ObjectOpenHashMap<K,V>

java.lang.Object

it.unimi.dsi.fastutil.objects.ObjectOpenHashMap<K,V>

public final class ObjectOpenHashMap<K,V>
extends java.lang.Object

NOTE: This source code was copied from the fastutil project, and has been modified.

A type-specific hash map with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a map. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create maps with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.

Author:

Sebastiano Vigna

See Also:

HashCommon, fastutil

Constructor Summary

Constructors

Constructor and Description
ObjectOpenHashMap() Creates a new hash map with initial expected DEFAULT_INITIAL_SIZE entries and DEFAULT_LOAD_FACTOR as load factor.
ObjectOpenHashMap(int expected) Creates a new hash map with DEFAULT_LOAD_FACTOR as load factor.
ObjectOpenHashMap(int expected, float f) Creates a new hash map.

Method Summary

Modifier and Type	Method and Description
void	clear()
boolean	containsKey(java.lang.Object k)
V	get(java.lang.Object k)
int	hashCode() Returns a hash code for this map.
boolean	isEmpty()
V	put(K k, V v)
V	remove(java.lang.Object k)
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectOpenHashMap

public ObjectOpenHashMap(int expected,
                         float f)

Creates a new hash map.

The actual table size will be the least power of two greater than expected/f.

Parameters:

expected - the expected number of elements in the hash map.

f - the load factor.

ObjectOpenHashMap

public ObjectOpenHashMap(int expected)

Creates a new hash map with DEFAULT_LOAD_FACTOR as load factor.

Parameters:

expected - the expected number of elements in the hash map.

ObjectOpenHashMap

public ObjectOpenHashMap()

Creates a new hash map with initial expected DEFAULT_INITIAL_SIZE entries and DEFAULT_LOAD_FACTOR as load factor.

Method Detail

put

public V put(K k,
             V v)

get

public V get(java.lang.Object k)

containsKey

public boolean containsKey(java.lang.Object k)

remove

public V remove(java.lang.Object k)

clear

public void clear()

size

public int size()

isEmpty

public boolean isEmpty()

hashCode

public int hashCode()

Returns a hash code for this map.

This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code for this map.