Geometry Construction

It is possible to activate several geometry builders at a time. We can think of it as a stack of activated geometry builders, each builder is pushed into the stack when activated and popped when it is de-activated.

An activated geometry builder B constructs exactly one type of geometry. When B de-activates, exactly two things may happen:

1. the geometry constructed by B is given to the FME feature: this occurs only if B is also the last activated geometry builder.
2. the geometry constructed by B is given to a previous geometry builder Bt: When B de-activates and B is not the last activated geometry builder, then the top activated geometry builder in the stack, say Bt, receives and integrates the geometry constructed by B into its own. For this to be meaningful, Bt must be willing to accept a geometry constructed by another geometry builder.