[wtp-dev] API Types that Inherit from Non-API Types

[Arthur Ryman <ryman@xxxxxxxxxx>]

The API scanning reports now flag refrerences
to non-API types as errors. Clearly, an API method must not have non-API
types as arguments, return value or exceptions. However, inheriting from
non-API types need further examination.

In general, an API class should hide
its implementation, so only inherit from non-API types when necessary.
If you do so, then the API must assume ownership of all inherited public
and protected methods since these are visible to clients. The API class
must shield clients from changes to the non-API class. For example, if
the non-API class removes a public or protected method, then the API class
must add it to avoid breaking clients.

The PMC discussed this topic on Tuesday
and arrived at the above policy. If you have other thoughts, please express
them now.

By cc, I am asking Jeem to give us the
official Eclipse position on this topic, or to help us formulate a position
if none currently exists.

Arthur Ryman,
Rational Desktop Tools Development

phone: +1-905-413-3077, TL 969-3077
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