com.metasolutions.util
Class SimpleHashMap

java.lang.Object
  com.metasolutions.util.SimpleHashMap

All Implemented Interfaces:

Serializable

public class SimpleHashMap
extends Object
implements Serializable

An optimized HashMap which is not part of the Collections Framework. This HashMap has been designed for execution speed over all other concerns. This HashMap uses a "power of 2" implementation with a singly-linked collision list. This implemenation uses 0 divisions, 1 multiplication in the constructor, and 1 multiplication per rehash() operation.

The HashMap can be futher optimized by using hashcodes instead of keys. This is an admittedly dangerous operation: the array returned from getKeys() would be missing keys if they were not specified in a put() operation. As a rule of thumb, if you would need to use a getKeys() or getHashCodes() operation, you should fill the map with all keys, or all hashcodes, respectively. Note that getHashCodes will always return all hashcodes, whether keys or hashcodes were used.

This implementation is thread-safe, but it should be noted that the Collection classes provided in the new java.util.concurrent package will undoubtedly be a superior solution for multithreaded applications.

Version:

0.9 May 29, 2005

Author:

Shawn Curry

See Also:

Serialized Form

Constructor Summary

SimpleHashMap()

SimpleHashMap(int cap)

Method Summary

void	clear()
Object	get(int hash)
Object	get(Object key)
int[]	getHashCodes()
Object[]	getKeys()
Object	put(int hash, Object value)
Object	put(Object key, Object value)
Object	remove(int hash)
Object	remove(Object key)
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleHashMap

public SimpleHashMap()

SimpleHashMap

public SimpleHashMap(int cap)

Method Detail

clear

public void clear()

size

public int size()

put

public Object put(Object key,
                  Object value)

put

public Object put(int hash,
                  Object value)

get

public Object get(Object key)

get

public Object get(int hash)

remove

public Object remove(Object key)

remove

public Object remove(int hash)

getHashCodes

public int[] getHashCodes()

getKeys

public Object[] getKeys()