er.extensions.concurrency

Class ERXJobLoadBalancer

java.lang.Object

er.extensions.concurrency.ERXJobLoadBalancer

public class ERXJobLoadBalancer
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ERXJobLoadBalancer.JobSet Describes which jobs (index mod modulo) the worker should attempt to process
static class	ERXJobLoadBalancer.WorkerIdentification Identifies a worker to the load balancer

Constructor Summary

Constructors

Constructor and Description
ERXJobLoadBalancer()

Method Summary

Modifier and Type	Method and Description
static void	createJobs(String workerType, int n)
void	heartbeat(ERXJobLoadBalancer.WorkerIdentification workerId) Signals to the load balancer that the worker identified is alive Clients should call this periodically, and certainly more often than the timeout
ERXJobLoadBalancer.JobSet	idSpace(ERXJobLoadBalancer.WorkerIdentification workerId)
static ERXJobLoadBalancer	jobLoadBalancer()
static void	main(String[] args)
protected String	pathForWorkerIdentification(ERXJobLoadBalancer.WorkerIdentification workerId)
static void	processJobs(String workerType, int workerNumber)
void	setTtlForWorkerType(String type, long ttl) Sets the timeout for a given worker type
protected File	sharedRoot()
String	sharedRootLocation()
long	ttlForWorkerType(String type)
static void	usage()
String	workerInstanceIdentification()

Methods inherited from class java.lang.Object

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

Constructor Detail

ERXJobLoadBalancer

public ERXJobLoadBalancer()

Method Detail

jobLoadBalancer

public static ERXJobLoadBalancer jobLoadBalancer()

sharedRootLocation

public String sharedRootLocation()

Returns:

the shared path where the state of the workers is stored

sharedRoot

protected File sharedRoot()

ttlForWorkerType

public long ttlForWorkerType(String type)

Parameters:

type -

Returns:

the ttl for a given worker type. An instance that has not called heartbeat for more than this TTL will be considered dead by the other instances

setTtlForWorkerType

public void setTtlForWorkerType(String type,
                                long ttl)

Sets the timeout for a given worker type

Parameters:

type -

ttl - (in milliseconds)

pathForWorkerIdentification

protected String pathForWorkerIdentification(ERXJobLoadBalancer.WorkerIdentification workerId)

heartbeat

public void heartbeat(ERXJobLoadBalancer.WorkerIdentification workerId)

Signals to the load balancer that the worker identified is alive Clients should call this periodically, and certainly more often than the timeout

Parameters:

workerId - which worker is alive

idSpace

public ERXJobLoadBalancer.JobSet idSpace(ERXJobLoadBalancer.WorkerIdentification workerId)

Parameters:

workerId -

Returns:

the JobSet that the worker should attempt to process Given a worker looks at the shared state and determine the id space (index mod module) they should be processing

workerInstanceIdentification

public String workerInstanceIdentification()

Returns:

a String suitable to identify this particular worker instance !! this string is not MT safe

main

public static void main(String[] args)

usage

public static void usage()

createJobs

public static void createJobs(String workerType,
                              int n)

processJobs

public static void processJobs(String workerType,
                               int workerNumber)