com.prosyst.util.hash
Class HashObjLongNS

java.lang.Object
  com.prosyst.util.hash.HashObjLongNS

Direct Known Subclasses:

HashObjLongS

public class HashObjLongNS
extends java.lang.Object

Hashtable for mapping Object keys to long values. The methods of this hashtable are not synchronized, and if used concurently must be externally synchronized

Field Summary

java.lang.Object[]	keys Used to enumerate the keys in the hash table.
int[]	next Can be used to check if a key or value is valid.
long[]	values Used to enumerate the values in the hash table.

Constructor Summary

HashObjLongNS()
Constructs an empty hash table with keys of type int and values af type Object.

HashObjLongNS(int capacity)
Constructs an empty hash table with keys of type int and values af type Object.

HashObjLongNS(int capacity, double lf)
Constructs an empty hash table with keys of type int and values of type Object.

Method Summary

long	get(java.lang.Object key) Returns an value which is mapped to the key key.
void	put(java.lang.Object key, long value) Adds in hashtable an element with key key and value value.
void	rehash() Rehashes the contents of the hashtable into a hashtable with a larger capacity.
long	remove(java.lang.Object key) Removes an element with the specified key from the table.
void	removeAll() Empties the hash table
int	size() Returns the count of elements currently in the table

Methods inherited from class java.lang.Object

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

Field Detail

keys

public java.lang.Object[] keys

Used to enumerate the keys in the hash table. The key at index i is valid only if

keys[i] != null

values

public long[] values

Used to enumerate the values in the hash table. The value at index i is valid only if

keys[i] != null

next

public int[] next

Can be used to check if a key or value is valid. The value or key at index i is valid if the following expression is true

next[i] != -1 && next[i] < next.length

Constructor Detail

HashObjLongNS

public HashObjLongNS()

Constructs an empty hash table with keys of type int and values af type Object. Uses default load factor (0.75) and default capacity (89)

HashObjLongNS

public HashObjLongNS(int capacity)

Constructs an empty hash table with keys of type int and values af type Object. Uses default load factor (0.75).

Parameters:

capacity - initial capacity of the table

Throws:

java.lang.IllegalArgumentException - if capacity < 1.

HashObjLongNS

public HashObjLongNS(int capacity,
                     double lf)

Constructs an empty hash table with keys of type int and values of type Object.

Parameters:

capacity - initial capacity of the table

lf - load factor ot the table

Throws:

java.lang.IllegalArgumentException - if capacity < 1 or lf < 0.0

Method Detail

put

public void put(java.lang.Object key,
                long value)

Adds in hashtable an element with key key and value value. If an element with the specified key is already in the table only change it's value.

Parameters:

key - the key of the inserted element

value - the value of the inserted element

get

public long get(java.lang.Object key)

Returns an value which is mapped to the key key. If there is no such a key, throws NoSuchElementException.

Parameters:

key - the key we are searching for

Returns:

the value this key is mapped to in the table.

Throws:

java.util.NoSuchElementException - if there is no element with the specified key.

remove

public long remove(java.lang.Object key)

Removes an element with the specified key from the table. throws NoSuchElementException if there is no element with this key.

Parameters:

key - the key of the element we want to remove

Throws:

java.util.NoSuchElementException - if there is no element with the specified key.

removeAll

public void removeAll()

Empties the hash table

rehash

public void rehash()

Rehashes the contents of the hashtable into a hashtable with a larger capacity. This method is called automatically when the number of keys in the hashtable exceeds this hashtable's capacity and load factor.

size

public int size()

Returns the count of elements currently in the table

Returns:

the count of elements