org.qbroker.common

Class HashChain

java.lang.Object

org.qbroker.common.HashChain

All Implemented Interfaces:

java.util.Comparator<int[]>

public class HashChain
extends java.lang.Object
implements java.util.Comparator<int[]>

HashChain contains a list of the unique keys, and the sorted integer values hashed from the replicas of these keys. These integer values have divided the entire number axis into plenty of intervals. Each key will have many intervals due to its replicas. But any interval belongs only to a specific key. Therefore, HashChain can be used to map a message to one of the keys in a consistent way. The method of add() and remove() are used to add/remove a key to/from HashChain. The method of map() returns the id of a specific key for the message. The number of the replicas is predfined.

The default hash method is MD5.

This is NOT MT-Safe. Therefore please use it with care.

Author:

yannanlu@yahoo.com

Constructor Summary

Constructors

Constructor and Description
HashChain(java.lang.String name)
HashChain(java.lang.String name, int capacity)
HashChain(java.lang.String name, int capacity, int numOfReplica)

Method Summary

Modifier and Type	Method and Description
int	add(java.lang.String key)
int	add(java.lang.String key, int weight) It adds the key to the KeyChain and returns its id
Browser	browser() returns a browser for all keys
void	clear()
int	compare(int[] a, int[] b) It compares a and b in the ascending order
void	dump()
int	getCapacity()
int	getID(java.lang.String key)
java.lang.String	getKey(int id)
int	getMeasure(java.lang.String key) returns the measure in the HashChain for the given node
int	getSize()
static void	main(java.lang.String[] args)
int	map(java.lang.String msg) It maps the msg to a key and returns its id upon success or -1 otherwise
int	remove(java.lang.String key) It removes the key from the HashChain and returns its id

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

HashChain

public HashChain(java.lang.String name,
                 int capacity,
                 int numOfReplica)

HashChain

public HashChain(java.lang.String name,
                 int capacity)

HashChain

public HashChain(java.lang.String name)

Method Detail

add

public int add(java.lang.String key,
               int weight)

It adds the key to the KeyChain and returns its id

add

public int add(java.lang.String key)

remove

public int remove(java.lang.String key)

It removes the key from the HashChain and returns its id

map

public int map(java.lang.String msg)

It maps the msg to a key and returns its id upon success or -1 otherwise

getMeasure

public int getMeasure(java.lang.String key)

returns the measure in the HashChain for the given node

getKey

public java.lang.String getKey(int id)

getID

public int getID(java.lang.String key)

browser

public Browser browser()

returns a browser for all keys

getCapacity

public int getCapacity()

getSize

public int getSize()

clear

public void clear()

compare

public int compare(int[] a,
                   int[] b)

It compares a and b in the ascending order

Specified by:

compare in interface java.util.Comparator<int[]>

dump

public void dump()

main

public static void main(java.lang.String[] args)