Module org.refcodes.controlflow
Package org.refcodes.controlflow

Class RetryCounter

  • All Implemented Interfaces:
    Retryable, org.refcodes.mixin.Abortable, org.refcodes.mixin.Restartable, org.refcodes.mixin.RetryCountAccessor, org.refcodes.mixin.RetryNumberAccessor
    public class RetryCounter
extends Object
implements Retryable, org.refcodes.mixin.RetryNumberAccessor, org.refcodes.mixin.RetryCountAccessor
    The RetryCounter can be used in loops to test whether a retry should take place and in case a retry is to take place, then a given period of time (delay) is waited and the internal retry counter is decremented. In case no more retries are "available" the business logic may act accordingly such as throwing an exception.

    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.

    The first call to nextRetry() 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 upon calling nextRetry() is extended by that exponential delay (being increased for each retry).

    ATTENTION: The first call the nextRetry() increments the retry counter getRetryCount() to be 1 and not 0, so the retry counter is actually a "try" counter, having the first "try" upon invoking nextRetry().

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface org.refcodes.mixin.RetryCountAccessor

        org.refcodes.mixin.RetryCountAccessor.RetryCountBuilder<B extends org.refcodes.mixin.RetryCountAccessor.RetryCountBuilder<B>>, org.refcodes.mixin.RetryCountAccessor.RetryCountMutator, org.refcodes.mixin.RetryCountAccessor.RetryCountProperty

      • Nested classes/interfaces inherited from interface org.refcodes.mixin.RetryNumberAccessor

        org.refcodes.mixin.RetryNumberAccessor.RetryNumberBuilder<B extends org.refcodes.mixin.RetryNumberAccessor.RetryNumberBuilder<B>>, org.refcodes.mixin.RetryNumberAccessor.RetryNumberMutator, org.refcodes.mixin.RetryNumberAccessor.RetryNumberProperty

    • Constructor Summary

      Constructors 
      Constructor Description
      RetryCounter​(int aRetryNumber)
      Constructs a retry retry counter by providing the number of retries with no delay before each retry.
      RetryCounter​(int aRetryNumber, long aRetryDelayInMs)
      Constructs a retry timeout counter by providing the number of retries and the delay before each retry.
      RetryCounter​(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.
      RetryCounter​(long aTotalDelayInMs, long aRetryDelayInMs)
      Constructs a retry timeout counter by providing the total delay time and the delay before each retry.

    • Constructor Detail

      • RetryCounter

        public RetryCounter​(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

      • RetryCounter

        public RetryCounter​(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 RetryCounter(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.

      • RetryCounter

        public RetryCounter​(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 (value of -1 represents an infinite number which can only be aborted via abort()).
        aRetryDelayInMs - The delay before each retry to wait in milliseconds. When less than or equal to 0, then the delay is skipped.

      • RetryCounter

        public RetryCounter​(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 nextRetry() increments the retry counter getRetryCount() to be 1 and not 0, so the retry counter is actually a "try" counter, having the first "try" upon invoking nextRetry(). -------------------------------------------------------------------------
        Specified by:
        nextRetry in interface Retryable
        Returns:
        True in case there is a next retry as of hasNextRetry().

      • getNextRetryDelayInMs

        public long getNextRetryDelayInMs()
        Calculates the next retry delay in milliseconds. This is the time the nextRetry() method will wait in case its rules match for doing a sleep.
        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 org.refcodes.mixin.RetryNumberAccessor
        Returns:
        The number of altogether retries.

      • getInitialRetryDelayInMs

        public long getInitialRetryDelayInMs()
        Returns the initial delay before each retry to wait in milliseconds. The getCurrentRetryDelayInMs() is calculated from the initial delay and the exponential retry delay added for each retry (not added for the first call to nextRetry()).
        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 getInitialRetryDelayInMs() with the 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. -------------------------------------------------------------------------
        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 nextRetry() is extended by that exponential delay (being increased for each retry): ------------------------------------------------------------------------- "(getRetryDelayInMs() + (Math.pow( 4, getRetryCount() - 1 ) * getExpRetryDelayExtensionInMs())" -------------------------------------------------------------------------
        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 nextRetry() increments the retry counter getRetryCount() to be 1 and not 0, so the retry counter is actually a "try" counter, having the first "try" upon invoking nextRetry(). -------------------------------------------------------------------------
        Specified by:
        getRetryCount in interface Retryable
        Specified by:
        getRetryCount in interface org.refcodes.mixin.RetryCountAccessor
        Returns:
        The number of retries used up so far

      • setRetryDelayInMs

        public void setRetryDelayInMs​(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.