/// <summary>
/// Retries while the given method has an exception and returns the value from the method.
/// </summary>
public static RetryResult <T> WhileException <T>(Func <T> retryMethod, TimeSpan?timeout = null, TimeSpan?interval = null, bool throwOnTimeout = false, string timeoutMessage = null)
{
var returnValue = default(T);
var result = WhileTrue(() => { returnValue = retryMethod(); return(false); }, timeout, interval, ignoreException: true, throwOnTimeout: throwOnTimeout, timeoutMessage: timeoutMessage);
var newResult = new RetryResult <T>();
if (result.HadException)
{
newResult.SetException(result.LastException);
}
newResult.Finish(returnValue, result.TimedOut);
return(newResult);
}
/// <summary>
/// Retries while the given method evaluates to true and returns the value from the method.
/// If it fails, it returns the default of <typeparamref name="T"/>.
/// </summary>
/// <typeparam name="T">The type of the return value.</typeparam>
/// <param name="retryMethod">The method which is retried.</param>
/// <param name="checkMethod">The method which is used to decide if a retry is needed or if the value is correct.</param>
/// <param name="timeout">The timeout when the retry aborts.</param>
/// <param name="interval">The interval of retries.</param>
/// <param name="throwOnTimeout">A flag indicating if it should throw on timeout.</param>
/// <param name="ignoreException">A flag indicating if it should retry on an exception.</param>
/// <param name="timeoutMessage">The message that should be added to the timeout exception in case a timeout occurs.</param>
/// <param name="lastValueOnTimeout">A flag indicating if the last value should be returned on timeout. Returns the default if the value could never be fetched.</param>
/// <param name="defaultOnTimeout">Allows to define a default value in case of a timeout.</param>
/// <returns>The value from <paramref name="retryMethod"/> or the default of <typeparamref name="T"/>.</returns>
public static RetryResult <T> While <T>(Func <T> retryMethod, Func <T, bool> checkMethod, TimeSpan?timeout = null, TimeSpan?interval = null, bool throwOnTimeout = false, bool ignoreException = false, string timeoutMessage = null, bool lastValueOnTimeout = false, T defaultOnTimeout = default(T))
{
var retryResult = new RetryResult <T>();
timeout = timeout ?? DefaultTimeout;
interval = interval ?? DefaultInterval;
var startTime = DateTime.UtcNow;
Exception lastException = null;
T lastValue = defaultOnTimeout;
do
{
retryResult.Iterations++;
try
{
lastValue = retryMethod();
if (!checkMethod(lastValue))
{
return(retryResult.Finish(lastValue));
}
}
catch (Exception ex)
{
if (!ignoreException)
{
throw;
}
lastException = ex;
retryResult.SetException(ex);
}
Thread.Sleep(interval.Value);
} while (!IsTimeoutReached(startTime, timeout.Value));
if (throwOnTimeout)
{
timeoutMessage = timeoutMessage ?? "Timeout occurred in retry";
throw new TimeoutException(timeoutMessage, lastException);
}
return(retryResult.Finish(lastValueOnTimeout ? lastValue : defaultOnTimeout, true));
}