A director for assembling flows, delegating to a FlowBuilder to construct a flow. This class encapsulates the algorithm for using a FlowBuilder to assemble a Flow properly. It acts as the director in the classic GoF builder pattern.

Flow assemblers may be used in a standalone, programmatic fashion as follows:

     FlowBuilder builder = ...;
     new FlowAssembler("myFlow", builder).assembleFlow();
     Flow flow = builder.getFlow();