internal static void Composite()
{
// <Composites>
CancellationTokenSource firstCancellationTokenSource = new();
CancellationChangeToken firstCancellationChangeToken = new(firstCancellationTokenSource.Token);
CancellationTokenSource secondCancellationTokenSource = new();
CancellationChangeToken secondCancellationChangeToken = new(secondCancellationTokenSource.Token);
CancellationTokenSource thirdCancellationTokenSource = new();
CancellationChangeToken thirdCancellationChangeToken = new(thirdCancellationTokenSource.Token);
var compositeChangeToken =
new CompositeChangeToken(
new IChangeToken[]
{
firstCancellationChangeToken,
secondCancellationChangeToken,
thirdCancellationChangeToken
});
Action <object?> callback = state => Console.WriteLine($"The {state} callback was invoked.");
// 1st, 2nd, 3rd, and 4th.
compositeChangeToken.RegisterChangeCallback(callback, "1st");
compositeChangeToken.RegisterChangeCallback(callback, "2nd");
compositeChangeToken.RegisterChangeCallback(callback, "3rd");
compositeChangeToken.RegisterChangeCallback(callback, "4th");
// It doesn't matter which cancellation source triggers the change.
// If more than one trigger the change, each callback is only fired once.
Random random = new();
int index = random.Next(3);
CancellationTokenSource[] sources = new[]
{
firstCancellationTokenSource,
secondCancellationTokenSource,
thirdCancellationTokenSource
};
sources[index].Cancel();
Console.WriteLine();
// Outputs:
// The 4th callback was invoked.
// The 3rd callback was invoked.
// The 2nd callback was invoked.
// The 1st callback was invoked.
// </Composites>
}
