ValuePipline -> ReferencePipeline

[Paul Sandoz]

Hi,

A change has been committed (thanks Mike) that may affect testers.

ValuePipeline has been renamed to ReferencePipeline.

StreamShape has been converted from an enum to an interface.

The motivation for this change is two fold:

1) a smoother integration for primitive streams; and

2) the potential for extensibility of stream types.

The methods of Stream implemented by ReferencePipeline now defer to the output shape of the intermediate operation to add a new tail to the pipeline. Same goes for the testing framework.

The key point here is that when we add a method to Stream say:

  IntStream mapToInt(IntMapper<T> mapper)

Then the ReferencePipeline implementing mapToInt does not need to refer to the implementation of IntStream, it only needs to refer to the appropriate operation.

Paul.