BeeeOn::ExponentialBackOff Class Reference

ExponentialBackOff implements the computation of delay when retrying an operation. It is usually used to lower load of a server. More...

#include <ExponentialBackOff.h>

Inheritance diagram for BeeeOn::ExponentialBackOff:

Data Structures
class	Config

Public Types
typedef Poco::SharedPtr < ExponentialBackOff >	Ptr
Public Types inherited from BeeeOn::BackOff
typedef Poco::SharedPtr< BackOff >	Ptr

Public Member Functions
void	applyConfig (const Config &config)
const Config &	config () const
Poco::Timespan	initialInterval () const
Poco::Timespan	maxInterval () const
Poco::Timespan	maxElapsedTime () const
double	randomizationFactor () const
double	multiplier () const
Poco::Timespan	nextInterval () const
Poco::Timespan	elapsed () const
Poco::Timespan	next () override
void	reset () override

Protected Member Functions
Poco::Timespan	nextRandom ()

Additional Inherited Members
Static Public Attributes inherited from BeeeOn::BackOff
static const Poco::Timespan	STOP = -1

Detailed Description

ExponentialBackOff implements the computation of delay when retrying an operation. It is usually used to lower load of a server.

The instance manages a time interval (e.g. 5 seconds) suitable for random generation of the delay (example random delayes: 1 second, 3,5 seconds). The time interval changes in each iteration by applying the multiplier (configures the expenential grow speed).

The time interval is in fact represented as <min, max>. The min and max are computed from the current time interval and the randomization factor. Than, the min is computed as min = current_interval * (1 - factor) and the max is computed as max = = current_interval * (1 + factor). This way, the initial time interval boundaries grow over time and gives lower probability to generate a time delay colliding with some other client.

The interval grows until the max interval limit is reached or until a given (real) time has elapsed. Thus, we are not generate delays indefinitely.

See Also

https://en.wikipedia.org/wiki/Exponential_backoff

google-http-java-client: com.google.api.client.util.ExponentialBackOff

Member Function Documentation

Timespan ExponentialBackOff::elapsed

(

)

const

Time elapsed from the last reset or from the initial creation of the ExponentialBackOff instance.

Timespan ExponentialBackOff::next ( )

overridevirtual

Returns

next timeout generated by the back-off algorithm.

Implements BeeeOn::BackOff.

Timespan ExponentialBackOff::nextInterval

(

)

const

Return next interval for the next computation.

void ExponentialBackOff::reset ( )

overridevirtual

Reset state of the back-off algorithm.

Implements BeeeOn::BackOff.

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The documentation for this class was generated from the following files:

• /var/lib/jenkins/workspace/beeeon-gateway-master/base/src/util/ExponentialBackOff.h
• /var/lib/jenkins/workspace/beeeon-gateway-master/base/src/util/ExponentialBackOff.cpp