/// <summary>Clean up the cache if necessary and close the context provided (if the flag indicates that processing was successful).</summary>
/// <param name="retryPolicy">The retry policy.</param>
/// <param name="context">The context.</param>
/// <param name="state">The state.</param>
/// <param name="succeeded">The succeeded.</param>
protected void Close(IRetryPolicy retryPolicy, IRetryContext context, IRetryState state, bool succeeded)
{
if (state != null)
{
if (succeeded)
{
this.retryContextCache.Remove(state.GetKey());
retryPolicy.Close(context);
}
}
else
{
retryPolicy.Close(context);
}
}
/// <summary>The register exception.</summary>
/// <param name="retryPolicy">The retry policy.</param>
/// <param name="state">The state.</param>
/// <param name="context">The context.</param>
/// <param name="e">The e.</param>
/// <exception cref="RetryException"></exception>
protected void RegisterThrowable(IRetryPolicy retryPolicy, IRetryState state, IRetryContext context, Exception e)
{
if (state != null)
{
var key = state.GetKey();
if (context.RetryCount > 0 && !this.retryContextCache.ContainsKey(key))
{
throw new RetryException(
"Inconsistent state for failed item key: cache key has changed. "
+ "Consider whether equals() or hashCode() for the key might be inconsistent, "
+ "or if you need to supply a better key");
}
this.retryContextCache.Put(key, context);
}
retryPolicy.RegisterException(context, e);
}
/// <summary>Delegate to the <see cref="IRetryPolicy"/> having checked in the cache for an existing value if the state is not null.</summary>
/// <param name="retryPolicy">The retry policy.</param>
/// <param name="state">The state.</param>
/// <returns>The Spring.Retry.Retry.IRetryContext, either a new one or the one used last time the same state was encountered.</returns>
protected IRetryContext Open(IRetryPolicy retryPolicy, IRetryState state)
{
if (state == null)
{
return(this.DoOpenInternal(retryPolicy));
}
var key = state.GetKey();
if (state.IsForceRefresh())
{
return(this.DoOpenInternal(retryPolicy));
}
// If there is no cache hit we can avoid the possible expense of the
// cache re-hydration.
if (!this.retryContextCache.ContainsKey(key))
{
// The cache is only used if there is a failure.
return(this.DoOpenInternal(retryPolicy));
}
var context = this.retryContextCache.Get(key);
if (context == null)
{
if (this.retryContextCache.ContainsKey(key))
{
throw new RetryException(
"Inconsistent state for failed item: no history found. "
+ "Consider whether equals() or hashCode() for the item might be inconsistent, "
+ "or if you need to supply a better ItemKeyGenerator");
}
// The cache could have been expired in between calls to
// containsKey(), so we have to live with this:
return(this.DoOpenInternal(retryPolicy));
}
return(context);
}
/// <summary>Extension point for subclasses to decide on behaviour after catching an
/// exception in a <see cref="IRetryCallback{T}"/>. Normal stateless behaviour is not
/// to rethrow, and if there is state we rethrow.</summary>
/// <param name="retryPolicy">The retry policy.</param>
/// <param name="context">The context.</param>
/// <param name="state">The state.</param>
/// <returns>The System.Boolean.</returns>
protected bool ShouldRethrow(IRetryPolicy retryPolicy, IRetryContext context, IRetryState state)
{
if (state == null)
{
return(false);
}
else
{
return(state.RollbackFor(context.LastException));
}
}
/// <summary>Actions to take after final attempt has failed. If there is state clean
/// up the cache. If there is a recovery callback, execute that and return
/// its result. Otherwise throw an exception.</summary>
/// <param name="recoveryCallback">The callback for recovery (might be null).</param>
/// <param name="context">The current retry context.</param>
/// <param name="state">The state.</param>
/// <returns>The T.</returns>
/// <typeparam name="T">Type T.</typeparam>
protected T HandleRetryExhausted <T>(Func <IRetryContext, T> recoveryCallback, IRetryContext context, IRetryState state)
{
if (state != null)
{
this.retryContextCache.Remove(state.GetKey());
}
if (recoveryCallback != null)
{
return(recoveryCallback.Invoke(context));
}
if (state != null)
{
Logger.Debug(m => m("Retry exhausted after last attempt with no recovery path."));
throw new ExhaustedRetryException("Retry exhausted after last attempt with no recovery path", context.LastException);
}
throw WrapIfNecessary(context.LastException);
}
protected T DoExecute <T>(object retryCallback, object recoveryCallback, IRetryState state)
{
if (retryCallback == null || (!(retryCallback is IRetryCallback <T>) & !(retryCallback is Func <IRetryContext, T>)))
{
throw new ArgumentException("retryCallback must be an IRetryCallback<T> or a Func<IRetryContext, T>");
}
if (recoveryCallback != null && (!(recoveryCallback is IRetryCallback <T>) & !(recoveryCallback is Func <IRetryContext, T>)))
{
throw new ArgumentException("recoveryCallback must be an IRecoveryCallback<T> or a Func<IRetryContext, T>");
}
var retryPolicy = this.retryPolicy;
var backOffPolicy = this.backOffPolicy;
// Allow the retry policy to initialise itself...
var context = this.Open(retryPolicy, state);
Logger.Trace(m => m("RetryContext retrieved: {0}", context));
// Make sure the context is available globally for clients who need
// it...
RetrySynchronizationManager.Register(context);
Exception lastException = null;
try
{
// Give clients a chance to enhance the context...
var running = retryCallback is IRetryCallback <T>?this.DoOpenInterceptors((IRetryCallback <T>) retryCallback, context) : this.DoOpenInterceptors((Func <IRetryContext, T>)retryCallback, context);
if (!running)
{
throw new TerminatedRetryException("Retry terminated abnormally by interceptor before first attempt");
}
// Get or Start the backoff context...
IBackOffContext backOffContext = null;
IAttributeAccessor attributeAccessor = null;
if (context is IAttributeAccessor)
{
attributeAccessor = context;
var resource = attributeAccessor.GetAttribute("backOffContext");
if (resource is IBackOffContext)
{
backOffContext = (IBackOffContext)resource;
}
}
if (backOffContext == null)
{
backOffContext = backOffPolicy.Start(context);
if (attributeAccessor != null && backOffContext != null)
{
attributeAccessor.SetAttribute("backOffContext", backOffContext);
}
}
// We allow the whole loop to be skipped if the policy or context
// already forbid the first try. This is used in the case of
// external retry to allow a recovery in handleRetryExhausted
// without the callback processing (which would throw an exception).
while (this.CanRetry(retryPolicy, context) && !context.ExhaustedOnly)
{
try
{
Logger.Debug(m => m("Retry: count={0}", context.RetryCount));
// Reset the last exception, so if we are successful
// the close interceptors will not think we failed...
lastException = null;
return(retryCallback is IRetryCallback <T>?((IRetryCallback <T>)retryCallback).DoWithRetry(context) : ((Func <IRetryContext, T>)retryCallback).Invoke(context));
}
catch (Exception e)
{
lastException = e;
if (retryCallback is IRetryCallback <T> )
{
this.DoOnErrorInterceptors((IRetryCallback <T>)retryCallback, context, e);
}
else
{
this.DoOnErrorInterceptors((Func <IRetryContext, T>)retryCallback, context, e);
}
try
{
this.RegisterThrowable(retryPolicy, state, context, e);
}
catch (Exception ex)
{
throw new TerminatedRetryException("Could not register exception", ex);
}
if (this.CanRetry(retryPolicy, context) && !context.ExhaustedOnly)
{
try
{
backOffPolicy.BackOff(backOffContext);
}
catch (BackOffInterruptedException ex)
{
lastException = e;
// back off was prevented by another thread - fail
// the retry
Logger.Debug(m => m("Abort retry because interrupted: count={0}", context.RetryCount));
throw;
}
}
Logger.Debug(m => m("Checking for rethrow: count={0}", context.RetryCount));
if (this.ShouldRethrow(retryPolicy, context, state))
{
Logger.Debug(m => m("Rethrow in retry for policy: count={0}", context.RetryCount));
throw WrapIfNecessary(e);
}
}
// A stateful attempt that can retry should have rethrown the
// exception by now - i.e. we shouldn't get this far for a
// stateful attempt if it can retry.
}
Logger.Debug(m => m("Retry failed last attempt: count={0}" + context.RetryCount));
if (context.ExhaustedOnly)
{
throw new ExhaustedRetryException("Retry exhausted after last attempt with no recovery path.", context.LastException);
}
if (recoveryCallback == null)
{
return(this.HandleRetryExhausted(default(IRecoveryCallback <T>), context, state));
}
else if (recoveryCallback is IRecoveryCallback <T> )
{
return(this.HandleRetryExhausted((IRecoveryCallback <T>)recoveryCallback, context, state));
}
else
{
return(this.HandleRetryExhausted((Func <IRetryContext, T>)recoveryCallback, context, state));
}
}
finally
{
this.Close(retryPolicy, context, state, lastException == null);
if (retryCallback is IRetryCallback <T> )
{
this.DoCloseInterceptors((IRetryCallback <T>)retryCallback, context, lastException);
}
else
{
this.DoCloseInterceptors((Func <IRetryContext, T>)retryCallback, context, lastException);
}
RetrySynchronizationManager.Clear();
}
}
/// <summary>The execute.</summary>
/// <param name="retryCallback">The retry callback.</param>
/// <param name="recoveryCallback">The recovery callback.</param>
/// <param name="retryState">The retry state.</param>
/// <returns>The T.</returns>
/// <typeparam name="T">Type T.</typeparam>
public T Execute <T>(Func <IRetryContext, T> retryCallback, Func <IRetryContext, T> recoveryCallback, IRetryState retryState)
{
return(this.DoExecute <T>(retryCallback, recoveryCallback, retryState));
}
/// <summary>The execute.</summary>
/// <param name="retryCallback">The retry callback.</param>
/// <param name="recoveryCallback">The recovery callback.</param>
/// <param name="retryState">The retry state.</param>
/// <returns>The T.</returns>
/// <typeparam name="T">Type T.</typeparam>
public T Execute <T>(IRetryCallback <T> retryCallback, IRecoveryCallback <T> recoveryCallback, IRetryState retryState)
{
return(this.DoExecute <T>(retryCallback, recoveryCallback, retryState));
}