159. Introducing layout flattening

Let’s suppose that we have the following nested model (the exact same model as in Problem 158):

SequenceLayout innerSeq
  = MemoryLayout.sequenceLayout(5, ValueLayout.JAVA_DOUBLE);
SequenceLayout outerSeq
  = MemoryLayout.sequenceLayout(10, innerSeq);

Next, we define a VarHandle via PathElement and we populate this model accordingly with some random data in a memory segment named segment (you can see the code listed in Problem 158).

Our goal is to take this nested model and obtain a flat model. So, instead of having 10 sequences of 5 double values each, we want one sequence of 50 double values. This can be achieved via the flatten() method, as follows:

SequenceLayout flatten = outerSeq.flatten();
VarHandle fhandle = flatten.varHandle(
  PathElement.sequenceElement());
for (int i = 0; i < flatten.elementCount(); i++) {
  System.out.printf("\nx = %.2f", fhandle.get(segment, i));
}

Notice the PathElement, which...