Package org.refcodes.controlflow

Class RetryCounterImpl

java.lang.Object

org.refcodes.controlflow.RetryCounterImpl

All Implemented Interfaces:

Retryable, RetryCounter, org.refcodes.mixin.Abortable, org.refcodes.mixin.Restartable

public class RetryCounterImpl
extends Object
implements RetryCounter

Implementation of the RetryCounter interface.

Constructor Summary

Constructors

Constructor	Description
RetryCounterImpl(int aRetryNumber)	Constructs a retry retry counter by providing the number of retries with no delay before each retry.
RetryCounterImpl(int aRetryNumber, long aRetryDelayInMs)	Constructs a retry timeout counter by providing the number of retries and the delay before each retry.
RetryCounterImpl(int aRetryNumber, long aRetryDelayInMs, long aExpRetryDelayExtensionInMs)	Constructs a retry timeout counter by providing the number of retries and the delay before each retry and taking an exponential delay extension into calculation: ------------------------------------------------------------------------- "(getRetryDelayInMs() + (Math.pow( 4, getRetryCount() - 1 ) * getExpRetryDelayExtensionInMs())" ------------------------------------------------------------------------- In case a delay greater than 0 is set, then each retry is being delayed by the according amount of milliseconds, in case no retries are left, then delaying is skipped.
RetryCounterImpl(long aTotalDelayInMs, long aRetryDelayInMs)	Constructs a retry timeout counter by providing the total delay time and the delay before each retry.

Method Summary

Modifier and Type	Method	Description
void	abort()
long	getCurrentRetryDelayInMs()	Returns the current delay before each retry to wait in milliseconds.
long	getExpRetryDelayExtensionInMs()	Returns the exponential retry delay extension time in milliseconds.
long	getInitialRetryDelayInMs()	Returns the initial delay before each retry to wait in milliseconds.
long	getNextRetryDelayInMs()	Calculates the next retry delay in milliseconds.
int	getRetryCount()	The current state regarding the retires.
int	getRetryNumber()	Returns the number of retires this instance allows altogether.
boolean	hasNextRetry()	Returns true in case not all retires have been used up.
boolean	nextRetry()	Tests whether a next retry is possible.
void	restart()
void	setRetryDelyInMs(long aRetryDelayInMs)	Sets the delay before each retry to wait in milliseconds.

Methods inherited from class java.lang.Object

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

Constructor Detail

RetryCounterImpl

public RetryCounterImpl(int aRetryNumber)

Constructs a retry retry counter by providing the number of retries with no delay before each retry.

Parameters:

aRetryNumber - Sets the number of retires this instance allows altogether

RetryCounterImpl

public RetryCounterImpl(long aTotalDelayInMs,
                        long aRetryDelayInMs)

Constructs a retry timeout counter by providing the total delay time and the delay before each retry. The total delay time is the total time this RetryCounter will delay till the last call of the nextRetry(). It does not take the time "lost" into account lost by business logic calling the RetryCounter. The actual caclultated number of retires may be a rounded one, depending whether the total delay divided by the retry delay has a reminder. Basically speaking this is a convenience constructor calling RetryCounterImpl(int, long, long) calculating the number of retires by: ------------------------------------------------------------------------- "aRetryNumber = (aTotalDelayInMs / aRetryDelayInMs)" -------------------------------------------------------------------------

Parameters:

aTotalDelayInMs - Sets the total delay time this instance allows altogether. From this number divided by the actual retry delay results in the number of retires.

aRetryDelayInMs - The delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped.

RetryCounterImpl

public RetryCounterImpl(int aRetryNumber,
                        long aRetryDelayInMs)

Constructs a retry timeout counter by providing the number of retries and the delay before each retry. In case a delay greater than 0 is set, then each retry is being delayed by the according amount of milliseconds, in case no retries are left, then delaying is skipped. A delay of 0 or smaller skips delaying altogether.

Parameters:

aRetryNumber - Sets the number of retires this instance allows altogether

aRetryDelayInMs - The delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped.

RetryCounterImpl

public RetryCounterImpl(int aRetryNumber,
                        long aRetryDelayInMs,
                        long aExpRetryDelayExtensionInMs)

Constructs a retry timeout counter by providing the number of retries and the delay before each retry and taking an exponential delay extension into calculation: ------------------------------------------------------------------------- "(getRetryDelayInMs() + (Math.pow( 4, getRetryCount() - 1 ) * getExpRetryDelayExtensionInMs())" ------------------------------------------------------------------------- In case a delay greater than 0 is set, then each retry is being delayed by the according amount of milliseconds, in case no retries are left, then delaying is skipped. In case an exponential delay extension is being set greater than 0, then the delay is extended accordingly. A delay of 0 or smaller skips delaying altogether.

Parameters:

aRetryNumber - Sets the number of retires this instance allows altogether

aRetryDelayInMs - The delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped.

aExpRetryDelayExtensionInMs - the exp retry delay extension in ms

Method Detail

nextRetry

public boolean nextRetry()

Tests whether a next retry is possible. In case this is true, then the retry count is incremented by one. In case this is not the first call to the retry counter, then the thread is delayed by the configured delay time. In case ------------------------------------------------------------------------- The first call does not delay as the first call is not considered to be a retry. In case an exponential retry delay extension time has been provided, then the retry delay is extended by that exponential delay being increased for each retry. ------------------------------------------------------------------------- ATTENTION: The first call the RetryCounter.nextRetry() increments the retry counter RetryCounter.getRetryCount() to be 1 and not 0, so the retry counter is actually a "try" counter, having the first "try" upon invoking RetryCounter.nextRetry(). -------------------------------------------------------------------------

Specified by:

nextRetry in interface Retryable

Specified by:

nextRetry in interface RetryCounter

Returns:

True in case there is a next retry as of Retryable.hasNextRetry().

getNextRetryDelayInMs

public long getNextRetryDelayInMs()

Calculates the next retry delay in milliseconds. This is the time the RetryCounter.nextRetry() method will wait in case its rules match for doing a sleep.

Specified by:

getNextRetryDelayInMs in interface RetryCounter

Returns:

The next retry delay in milliseconds.

hasNextRetry

public boolean hasNextRetry()

Returns true in case not all retires have been used up.

Specified by:

hasNextRetry in interface Retryable

Returns:

True in case there are retries left true in case all retries elapsed.

restart

public void restart()

Specified by:

restart in interface org.refcodes.mixin.Restartable

abort

public void abort()

Specified by:

abort in interface org.refcodes.mixin.Abortable

getRetryNumber

public int getRetryNumber()

Returns the number of retires this instance allows altogether.

Specified by:

getRetryNumber in interface RetryCounter

Returns:

The number of altogether retries.

getInitialRetryDelayInMs

public long getInitialRetryDelayInMs()

Returns the initial delay before each retry to wait in milliseconds. The RetryCounter.getCurrentRetryDelayInMs() is calculated from the initial delay and the exponential retry delay added for each retry (not added for the first call to RetryCounter.nextRetry()).

Specified by:

getInitialRetryDelayInMs in interface RetryCounter

Returns:

The delay to being set in milliseconds.

getCurrentRetryDelayInMs

public long getCurrentRetryDelayInMs()

Returns the current delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped. The current delay is calculated by extending the RetryCounter.getInitialRetryDelayInMs() with the RetryCounter.getExpRetryDelayExtensionInMs() per retry. ------------------------------------------------------------------------- The current retry delay gets incremented for each retry by an exponential retry delay extension time calculated from in case it is greater than 0. -------------------------------------------------------------------------

Specified by:

getCurrentRetryDelayInMs in interface RetryCounter

Returns:

The delay to being set in milliseconds.

getExpRetryDelayExtensionInMs

public long getExpRetryDelayExtensionInMs()

Returns the exponential retry delay extension time in milliseconds. In case an exponential retry delay extension time has been provided, then the retry delay upon calling RetryCounter.nextRetry() is extended by that exponential delay (being increased for each retry): ------------------------------------------------------------------------- "(getRetryDelayInMs() + (Math.pow( 4, getRetryCount() - 1 ) * getExpRetryDelayExtensionInMs())" -------------------------------------------------------------------------

Specified by:

getExpRetryDelayExtensionInMs in interface RetryCounter

Returns:

The exponential retry delay extension time in milliseconds.

getRetryCount

public int getRetryCount()

The current state regarding the retires. It specifies at which retry we currently are. ------------------------------------------------------------------------- ATTENTION: The first call the RetryCounter.nextRetry() increments the retry counter RetryCounter.getRetryCount() to be 1 and not 0, so the retry counter is actually a "try" counter, having the first "try" upon invoking RetryCounter.nextRetry(). -------------------------------------------------------------------------

Specified by:

getRetryCount in interface Retryable

Specified by:

getRetryCount in interface RetryCounter

Returns:

The number of retries used up so far

setRetryDelyInMs

public void setRetryDelyInMs(long aRetryDelayInMs)

Sets the delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped.

Parameters:

aRetryDelayInMs - The delay to be set in milliseconds.