Cactus API design rules
Most of these rules are extracted from the excellent
How to Use the Eclipse API article
by Jim des Rivieres.
To try to draw the line more starkly, the code base for the platform
is separated into API/SPI and non-API/non-SPI packages, with all
API/SPI elements being declared in designated API/SPI packages.
Everything else is considered internal implementation detail and off
limits to all clients. Legitimate client code must never reference
the names of non-API/non-SPI elements (not even using Java
reflection). In some cases, the Java language's name accessibility
rules are used to disallow illegal references. However, there are
many cases where this is simply not possible. Observing this one
simple rule avoids the problem completely:
Stick to officially documented APIs/SPIs. Only reference packages
that are documented in the published API/SPI Javadoc for the
component. Never reference a package belonging to another component
that has "internal" in its name --- these are never API/SPI. Never
reference a package for which there is no published API/SPI Javadoc
--- these are not API/SPI either.
No public methods in internal packages
In order to preserve binary compatibility, no user public API/SPI
must be located in internal packages.
No public class exposed as much as possible
Only interfaces should be exposed in the public API/SPI (as much as
possible). This will satisfy binary compatibility and allow future
extensibility. Of course, in some cases, it is not possible. For
ServletTestCase has to be a class as it
contains logic required to transform a JUnit test case into a Cactus
test case. Same for
ServletTestSuite as the way to use
it in a JUnit
suite() method is to create an instance