org.qbroker.common

Class UniqueID

java.lang.Object

org.qbroker.common.UniqueID

public class UniqueID
extends java.lang.Object

UniqueID generates unique and monotonously increaing IDs. It supports three different uniqueness scopes, JVM wide, machine wide and globe wide.

The unique ID is a 16 byte HexString on globe scope, 12 byte HexString on machine scope and 10 byte HexString on JVM scope. For a full length HexString, the first 8 bytes are for timestamp, the next 2 byes for sequence number and next 2 byes for pid of JVM and the last 4 bytes for the hostid of the machine. Currently, hostid is not implemented yet.

Since Win2K does not support hostid, you should use the IP address to identify the machine. Please remember, there may be overlap between some hostid and ip. Therefore, please use ip across entire cluster if there is any Win2K node.

Author:

yannanlu@yahoo.com

Field Summary

Fields

Modifier and Type	Field and Description
static int	SCOPE_GLOBE
static int	SCOPE_JVM
static int	SCOPE_MACHINE
static int	SCOPE_UNIVERSE

Constructor Summary

Constructors

Constructor and Description
UniqueID(int scope)

Method Summary

Modifier and Type	Method and Description
java.lang.String	getNext()
static byte[]	toBytes(java.lang.String uid)
static java.lang.String	toString(byte[] b)

Methods inherited from class java.lang.Object

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

Field Detail

SCOPE_JVM

public static final int SCOPE_JVM

See Also:

Constant Field Values

SCOPE_MACHINE

public static final int SCOPE_MACHINE

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Constant Field Values

SCOPE_GLOBE

public static final int SCOPE_GLOBE

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Constant Field Values

SCOPE_UNIVERSE

public static final int SCOPE_UNIVERSE

See Also:

Constant Field Values

Constructor Detail

UniqueID

public UniqueID(int scope)

Method Detail

getNext

public java.lang.String getNext()

toBytes

public static byte[] toBytes(java.lang.String uid)

toString

public static java.lang.String toString(byte[] b)