The Parallel composite acts in a similar way to the Sequence composite. It has a set of child tasks, and it runs them until one of them fails. At that point, the Parallel task as a whole fails. If all of the child tasks complete successfully, the Parallel task returns with success. In this way, it is identical to the Sequence task and its non-deterministic variations. The difference is the way it runs those tasks. Rather than running them one at a time, it runs them all simultaneously. We can think of it as creating a bunch of new threads, one per child, and setting the child tasks off together.

[SerializableAttribute]
public class Parallel : Composite<ParallelData>

<SerializableAttribute>
Public Class Parallel
	Inherits Composite(Of ParallelData)

[SerializableAttribute]
public ref class Parallel : public Composite<ParallelData^>

[<SerializableAttribute>]
type Parallel =  
    class
        inherit Composite<ParallelData>
    end