/// <summary>
/// Initializes a new instance of the <see cref="AsyncLazy<T>"/> class.
/// </summary>
/// <param name="factory">The asynchronous delegate that is invoked to produce the value when it is needed. May not be <c>null</c>.</param>
public AsyncLazy(Func <Task <T> > factory, AsyncLazyFlags flags = AsyncLazyFlags.None)
{
var func = factory;
if ((flags & AsyncLazyFlags.ExecuteOnThreadPool) == AsyncLazyFlags.ExecuteOnThreadPool)
{
func = () => System.Threading.Tasks.Task.Run(factory);
}
_instance = new Lazy <Task <T> >(func);
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncLazy<T>"/> class.
/// </summary>
/// <param name="factory">The asynchronous delegate that is invoked to produce the value when it is needed. May not be <c>null</c>.</param>
/// <param name="flags">Flags to influence async lazy semantics.</param>
public AsyncLazy(Func <Task <T> > factory, AsyncLazyFlags flags = AsyncLazyFlags.None)
{
var f = factory ?? throw new ArgumentNullException(nameof(factory));
if ((flags & AsyncLazyFlags.ExecuteOnCallingThread) != AsyncLazyFlags.ExecuteOnCallingThread)
{
f = RunOnThreadPool(f);
}
_mutex = new object();
_instance = new Lazy <Task <T> >(f);
}
/// <summary>
/// Initializes a new instance of the <see cref="AsyncLazy<T>"/> class.
/// </summary>
/// <param name="factory">The asynchronous delegate that is invoked to produce the value when it is needed. May not be <c>null</c>.</param>
/// <param name="flags">Flags to influence async lazy semantics.</param>
public AsyncLazy(Func <Task <T> > factory, AsyncLazyFlags flags = AsyncLazyFlags.None)
{
_factory = factory ?? throw new ArgumentNullException(nameof(factory));
if ((flags & AsyncLazyFlags.RetryOnFailure) == AsyncLazyFlags.RetryOnFailure)
{
_factory = RetryOnFailure(_factory);
}
if ((flags & AsyncLazyFlags.ExecuteOnCallingThread) != AsyncLazyFlags.ExecuteOnCallingThread)
{
_factory = RunOnThreadPool(_factory);
}
_mutex = new object();
_instance = new Lazy <Task <T> >(_factory);
}
public AsyncLazy(Func <Task <TResult> > func, AsyncLazyFlags flag = AsyncLazyFlags.None)
{
if (func == null)
{
throw new ArgumentNullException(nameof(func));
}
_factory = func;
if ((flag & AsyncLazyFlags.RetryOnFailure) == AsyncLazyFlags.RetryOnFailure)
{
_factory = RetryOnFailure(_factory);
}
if ((flag & AsyncLazyFlags.ExecuteOnCallingThread) != AsyncLazyFlags.ExecuteOnCallingThread)
{
_factory = RunOnThreadPool(_factory);
}
_mutex = new object();
_instance = new Lazy <Task <TResult> >(func);
}
/// <summary>
/// startLazy is only for demo purpose ;-)
/// </summary>
public ObjectWithLazy(bool startLazy, AsyncLazyFlags asyncLazyFlags = AsyncLazyFlags.None)
{
_lazyNumber1 = new AsyncLazy <int>(async() =>
{
await Task.Delay(1500).ConfigureAwait(false);
return(42);
});
_lazyNumber2 = new AsyncLazy <int>(async() =>
{
await Task.Delay(1500).ConfigureAwait(false);
return(42);
});
if (startLazy)
{
_lazyNumber1.Start();
_lazyNumber2.Start();
}
}