public Task<AggregateOperationsResult> ProcessQueue(IEnumerable<IOperationViewModel> operations,
CancellationToken token)
{
foreach (var operation in operations)
{
// Check if previous previousOperation failed.
var previousOperation = GetPreviousItem(operations, operation);
if (token.IsCancellationRequested || !this.CanContinue(previousOperation))
{
break;
}
operation.State = OperationState.InProgress;
eventAggregator.PublishOnUIThread(new LogEntry(operation.Description, LogEntrySeverity.Info,
LogEntrySource.UI));
var result = new OperationResult();
try
{
token.ThrowIfCancellationRequested();
result = operation.Process();
LogResultMessages(result);
resultHandlershandle[result.State](result, operation);
}
catch (OperationCanceledException)
{
resultHandlershandle[OperationResultState.Canceled](result, operation);
}
catch (Exception e)
{
eventAggregator.PublishOnUIThread(
new LogEntry(string.Format("Unhandled exception occurred: {0}", e.Message),
LogEntrySeverity.Error, LogEntrySource.UI));
}
}
return Task.FromResult(CalculateResult(operations));
}
private void LogResultMessages(OperationResult result)
{
const int maxEntriesToShow = 1500;
if (result.LogEntries.Count <= maxEntriesToShow)
{
this.PublishLogEntries(result.LogEntries);
}
else
{
var lastEntries =
result.LogEntries.AsEnumerable<LogEntry>().Skip(Math.Max(0, result.LogEntries.Count - maxEntriesToShow));
this.PublishLogEntries(lastEntries);
eventAggregator.PublishOnUIThread(new LogEntry("The converter returned " + result.LogEntries.Count + " lines.", LogEntrySeverity.Warning, LogEntrySource.UI));
eventAggregator.PublishOnUIThread(new LogEntry("Only showing the last " + maxEntriesToShow, LogEntrySeverity.Warning, LogEntrySource.UI));
}
}
private void HandleWarning(OperationResult result, IOperationViewModel operation)
{
operation.State = OperationState.CompleteWithWarnings;
eventAggregator.PublishOnUIThread(
new LogEntry(string.Format("{0} completed with warnings!", operation.Description),
LogEntrySeverity.Warning, LogEntrySource.UI));
}
private void HandleSuccess(OperationResult result, IOperationViewModel operation)
{
operation.State = OperationState.Success;
eventAggregator.PublishOnUIThread(
new LogEntry(string.Format("{0} completed successfully.", operation.Description), LogEntrySeverity.Info,
LogEntrySource.UI));
}
private void HandleErrors(OperationResult result, IOperationViewModel operation)
{
operation.State = OperationState.Failed;
eventAggregator.PublishOnUIThread(new LogEntry(string.Format("{0} failed!", operation.Description),
LogEntrySeverity.Error, LogEntrySource.UI));
}
private void HandleCancellation(OperationResult result, IOperationViewModel operation)
{
eventAggregator.PublishOnUIThread(
new LogEntry(string.Format("Operation {0} canceled.", operation.Description), LogEntrySeverity.Warning,
LogEntrySource.UI));
}
