net.lecousin.framework.collections.map

Class HalfByteHashMap<T>

java.lang.Object

net.lecousin.framework.collections.map.HalfByteHashMap<T>

Type Parameters:

T - type of elements

All Implemented Interfaces:

ByteMap<T>, PrimitiveMap<T>

public class HalfByteHashMap<T>
extends Object
implements ByteMap<T>

This class uses the 4 lower bits of a byte as a hash code, then for each hash code associates an ordered array.
In other words, it splits bytes over 16 buckets, each bucket containing up to 16 key-value pairs.
The insert and remove operations are costly because we need to reallocate and order the arrays, but the get operation is fast, while using reasonable amount of memory.

Constructor Summary

Constructors

Constructor and Description
HalfByteHashMap() Constructor.

Method Summary

Modifier and Type	Method and Description
void	clear() Clear all elements of this map.
boolean	containsKey(byte key) Return true if the map contains the given key.
T	get(byte key) Get a value.
boolean	isEmpty() Return true if this map is empty.
T	put(byte key, T element) Put a value and return the previous value associated with this key, or null.
T	remove(byte key) Remove a value.
int	size() Return the number of elements.
Iterator<T>	values() Iterates on values.

Methods inherited from class java.lang.Object

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

Constructor Detail

HalfByteHashMap

public HalfByteHashMap()

Constructor.

Method Detail

get

public T get(byte key)

Description copied from interface: ByteMap

Get a value.

Specified by:

get in interface ByteMap<T>

put

public T put(byte key,
             T element)

Description copied from interface: ByteMap

Put a value and return the previous value associated with this key, or null.

Specified by:

put in interface ByteMap<T>

size

public int size()

Description copied from interface: PrimitiveMap

Return the number of elements.

Specified by:

size in interface PrimitiveMap<T>

isEmpty

public boolean isEmpty()

Description copied from interface: PrimitiveMap

Return true if this map is empty.

Specified by:

isEmpty in interface PrimitiveMap<T>

containsKey

public boolean containsKey(byte key)

Description copied from interface: ByteMap

Return true if the map contains the given key.

Specified by:

containsKey in interface ByteMap<T>

remove

public T remove(byte key)

Description copied from interface: ByteMap

Remove a value.

Specified by:

remove in interface ByteMap<T>

clear

public void clear()

Description copied from interface: PrimitiveMap

Clear all elements of this map.

Specified by:

clear in interface PrimitiveMap<T>

values

public Iterator<T> values()

Description copied from interface: PrimitiveMap

Iterates on values.

Specified by:

values in interface PrimitiveMap<T>