yass.backoff
Class GeometricProgressionBackoffManager

java.lang.Object
  yass.backoff.BackoffManager
      yass.backoff.GeometricProgressionBackoffManager

All Implemented Interfaces:

Advanceable

public class GeometricProgressionBackoffManager
extends BackoffManager

Backoff manager in which the sequence of backoff periods forms a geometric progression. This class generates similar behaviour to that of ExponentialBackoffManager but with a different style of parameterisation which may be more convenient under some circumstances.

Nested Class Summary

Nested classes/interfaces inherited from class yass.backoff.BackoffManager

BackoffManager.BackoffState

Field Summary

protected int	backoffCycleLimit The maximum permitted number of backoff cycles before timeout
protected double	ratio The ratio by which the previous backoff period is multiplied to find the next backoff period

Fields inherited from class yass.backoff.BackoffManager

backoffCyclesCompleted, currentBackoffPeriod, currentBackoffRemaining, initialBackoffPeriod, nextBackoffPeriod, state

Constructor Summary

GeometricProgressionBackoffManager(double initialBackoffPeriod, double ratio, int backoffCycleLimit)
Creates a new instance of GeometricProgressionBackoffManager

Method Summary

boolean	attemptBackoff() Attempts to initiate a new backoff period, the duration of which is the next term in the geometric sequence
BackoffManager	clonePrototype() Obtains a new GeometricProgressionBackoffManager instance, using the called instance as a template instance
int	getBackoffCycleLimit() Obtains the maximum permitted number of backoff cycles before timeout
double	getRatio() Obtains the ratio by which adjacent terms in the geometric sequence of backoff times differ

Methods inherited from class yass.backoff.BackoffManager

advanceTime, checkBackoffStatePreconditions, getBackoffCyclesCompleted, getCurrentBackoffPeriod, getCurrentBackoffRemaining, getInitialBackoffPeriod, getNextBackoffPeriod, getState, toString

Methods inherited from class java.lang.Object

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

Field Detail

ratio

protected double ratio

The ratio by which the previous backoff period is multiplied to find the next backoff period

backoffCycleLimit

protected int backoffCycleLimit

The maximum permitted number of backoff cycles before timeout

Constructor Detail

GeometricProgressionBackoffManager

public GeometricProgressionBackoffManager(double initialBackoffPeriod,
                                          double ratio,
                                          int backoffCycleLimit)

Creates a new instance of GeometricProgressionBackoffManager

Parameters:

initialBackoffPeriod - the initial backoff period, in seconds

ratio - ratio by which adjacent terms in geometric sequence of backoff times differ

backoffCycleLimit - maximum permitted number of backoff cycles before timeout

Method Detail

clonePrototype

public BackoffManager clonePrototype()

Obtains a new GeometricProgressionBackoffManager instance, using the called instance as a template instance

Specified by:

clonePrototype in class BackoffManager

Returns:

the GeometricProgressionBackoffManager copy instance

attemptBackoff

public boolean attemptBackoff()
                       throws BackoffException

Attempts to initiate a new backoff period, the duration of which is the next term in the geometric sequence

Specified by:

attemptBackoff in class BackoffManager

Returns:

true if a new backoff period is permitted and has been initiated, otherwise false

Throws:

BackoffException - if called when the backoff manager is not currently in a READY state

getRatio

public double getRatio()

Obtains the ratio by which adjacent terms in the geometric sequence of backoff times differ

Returns:

the ratio by which adjacent terms in the geometric sequence of backoff times differ

getBackoffCycleLimit

public int getBackoffCycleLimit()

Obtains the maximum permitted number of backoff cycles before timeout

Returns:

the maximum permitted number of backoff cycles before timeout