/// <summary>
/// see RepeatTemplate#WaitForResults
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
protected override bool WaitForResults(IRepeatInternalState state)
{
IResultQueue <IResultHolder> queue = ((ResultQueueInternalState)state).ResultQueue;
bool result = true;
while (queue.IsExpecting())
{
// Careful that no runnables that are not going to finish ever get
// onto the queue, else this may block forever.
IResultHolder future;
try
{
future = queue.Take();
}
catch (ThreadInterruptedException)
{
Thread.CurrentThread.Interrupt();
throw new RepeatException("InterruptedException while waiting for result.");
}
if (future.Error != null)
{
state.GetExceptions().Add(future.Error);
result = false;
}
else
{
RepeatStatus status = future.Result;
result = result && CanContinue(status);
ExecuteAfterInterceptors(future.Context, status);
}
}
Assert.State(queue.IsEmpty(), "Future results queue should be empty at end of batch.");
return(result);
}
/// <summary>
/// Use the TaskExecutor to generate a result. The
/// internal state in this case is a queue of unfinished result holders of
/// IResultHolder. The holder with the return value should not be
/// on the queue when this method exits. The queue is scoped in the calling
/// method so there is no need to synchronize access.
/// </summary>
/// <param name="context"></param>
/// <param name="callback"></param>
/// <param name="state"></param>
/// <returns></returns>
protected override RepeatStatus GetNextResult(IRepeatContext context, RepeatCallback callback,
IRepeatInternalState state)
{
ExecutingRunnable runnable;
IResultQueue <IResultHolder> queue = ((ResultQueueInternalState)state).ResultQueue;
do
{
// Wrap the callback in a runnable that will add its result to the
// queue when it is ready.
runnable = new ExecutingRunnable(callback, context, queue);
// Tell the runnable that it can expect a result. This could have
// been in-lined with the constructor, but it might block, so it's
// better to do it here, since we have the option (it's a private
// class).
runnable.Expect();
//Start the task possibly concurrently / in the future.
_taskExecutor.Execute(new Task(delegate { runnable.Run(); }));
// Allow termination policy to update its state. This must happen
// immediately before or after the call to the task executor.
Update(context);
// Keep going until we get a result that is finished, or early
// termination...
}while (queue.IsEmpty() && !IsComplete(context));
IResultHolder result = queue.Take();
if (result.Error != null)
{
throw result.Error;
}
return(result.Result);
}
/// <summary>
/// see RepeatTemplate#WaitForResults
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
protected override bool WaitForResults(IRepeatInternalState state)
{
IResultQueue<IResultHolder> queue = ((ResultQueueInternalState)state).ResultQueue;
bool result = true;
while (queue.IsExpecting())
{
// Careful that no runnables that are not going to finish ever get
// onto the queue, else this may block forever.
IResultHolder future;
try
{
future = queue.Take();
}
catch (ThreadInterruptedException)
{
Thread.CurrentThread.Interrupt();
throw new RepeatException("InterruptedException while waiting for result.");
}
if (future.Error != null)
{
state.GetExceptions().Add(future.Error);
result = false;
}
else
{
RepeatStatus status = future.Result;
result = result && CanContinue(status);
ExecuteAfterInterceptors(future.Context, status);
}
}
Assert.State(queue.IsEmpty(), "Future results queue should be empty at end of batch.");
return result;
}
/// <summary>
/// Use the TaskExecutor to generate a result. The
/// internal state in this case is a queue of unfinished result holders of
/// IResultHolder. The holder with the return value should not be
/// on the queue when this method exits. The queue is scoped in the calling
/// method so there is no need to synchronize access.
/// </summary>
/// <param name="context"></param>
/// <param name="callback"></param>
/// <param name="state"></param>
/// <returns></returns>
protected override RepeatStatus GetNextResult(IRepeatContext context, RepeatCallback callback,
IRepeatInternalState state)
{
ExecutingRunnable runnable;
IResultQueue<IResultHolder> queue = ((ResultQueueInternalState)state).ResultQueue;
do
{
// Wrap the callback in a runnable that will add its result to the
// queue when it is ready.
runnable = new ExecutingRunnable(callback, context, queue);
// Tell the runnable that it can expect a result. This could have
// been in-lined with the constructor, but it might block, so it's
// better to do it here, since we have the option (it's a private
// class).
runnable.Expect();
//Start the task possibly concurrently / in the future.
_taskExecutor.Execute(new Task(delegate { runnable.Run(); }));
// Allow termination policy to update its state. This must happen
// immediately before or after the call to the task executor.
Update(context);
// Keep going until we get a result that is finished, or early
// termination...
}
while (queue.IsEmpty() && !IsComplete(context));
IResultHolder result = queue.Take();
if (result.Error != null)
{
throw result.Error;
}
return result.Result;
}
/// <summary>
///
/// </summary>
/// <param name="callback"></param>
/// <returns></returns>
private RepeatStatus ExecuteInternal(RepeatCallback callback)
{
// Reset the termination policy if there is one...
IRepeatContext context = Start();
// Make sure if we are already marked complete before we start then no
// processing takes place.
bool running = !IsMarkedComplete(context);
foreach (IRepeatListener interceptor in _listeners)
{
interceptor.Open(context);
running = running && !IsMarkedComplete(context);
if (!running)
{
break;
}
}
// Return value, default is to allow continued processing.
RepeatStatus result = RepeatStatus.Continuable;
IRepeatInternalState state = CreateInternalState(context);
// This is the list of exceptions thrown by all active callbacks
ICollection <System.Exception> exceptions = state.GetExceptions();
// Keep a separate list of exceptions we handled that need to be
// rethrown
ICollection <System.Exception> deferred = new List <System.Exception>();
try
{
while (running)
{
#region WhileRunning
/*
* Run the before interceptors here, not in the task executor so
* that they all happen in the same thread - it's easier for
* tracking batch status, amongst other things.
*/
foreach (IRepeatListener interceptor in _listeners)
{
interceptor.Before(context);
// Allow before interceptors to veto the batch by setting
// flag.
running = running && !IsMarkedComplete(context);
}
// Check that we are still running (should always be true) ...
if (running)
{
#region Running
try
{
result = GetNextResult(context, callback, state);
ExecuteAfterInterceptors(context, result);
}
catch (System.Exception exception)
{
DoHandle(exception, context, deferred);
}
// N.B. the order may be important here:
if (IsComplete(context, result) || IsMarkedComplete(context) || deferred.Any())
{
running = false;
}
#endregion
}
#endregion
}
result = result.And(WaitForResults(state));
foreach (System.Exception exception in exceptions)
{
DoHandle(exception, context, deferred);
}
// Explicitly drop any references to internal state...
// useless ?
state = null;
}
/*
* No need for explicit catch here - if the business processing threw an
* exception it was already handled by the helper methods. An exception
* here is necessarily fatal.
*/
finally
{
#region HandleFinally
HandleFinally(deferred, _listeners, context);
#endregion
}
return(result);
}
/// <summary>
/// If necessary, wait for results to come back from remote or concurrent
/// processes. By default does nothing and returns true.
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
protected virtual bool WaitForResults(IRepeatInternalState state)
{
// no-op by default
return(true);
}
/// <summary>
/// Get the next completed result, possibly executing several callbacks until
/// one finally finishes. Normally a subclass would have to override both
/// this method and <see cref="CreateInternalState"/> because the
/// implementation of this method would rely on the details of the internal
/// state.
/// </summary>
/// <param name="context"></param>
/// <param name="callback"></param>
/// <param name="state"></param>
/// <returns></returns>
/// <exception cref="Exception"> </exception>
protected virtual RepeatStatus GetNextResult(IRepeatContext context, RepeatCallback callback, IRepeatInternalState state)
{
Update(context);
if (Logger.IsDebugEnabled)
{
Logger.Debug("Repeat operation about to start at count={0}", context.GetStartedCount());
}
return(callback(context)); //"DoInInteration"
}
/// <summary>
/// If necessary, wait for results to come back from remote or concurrent
/// processes. By default does nothing and returns true.
/// </summary>
/// <param name="state"></param>
/// <returns></returns>
protected virtual bool WaitForResults(IRepeatInternalState state)
{
// no-op by default
return true;
}
/// <summary>
/// Get the next completed result, possibly executing several callbacks until
/// one finally finishes. Normally a subclass would have to override both
/// this method and <see cref="CreateInternalState"/> because the
/// implementation of this method would rely on the details of the internal
/// state.
/// </summary>
/// <param name="context"></param>
/// <param name="callback"></param>
/// <param name="state"></param>
/// <returns></returns>
/// <exception cref="Exception"> </exception>
protected virtual RepeatStatus GetNextResult(IRepeatContext context, RepeatCallback callback, IRepeatInternalState state)
{
Update(context);
if (Logger.IsDebugEnabled)
{
Logger.Debug("Repeat operation about to start at count={0}", context.GetStartedCount());
}
return callback(context); //"DoInInteration"
}
