PGPPublicKeyRing from PGPSecretKeyRing

Hi!

I'm currently working with BouncyCastle on an OpenPGP Java project. For
that reason I have to create OpenPGP key pairs for the user.

I created a builder that returns a PGPSecretKeyRing as result of the
build() method. Now for convenience I would like to be able to easily
retrieve the PGPPublicKeyRing from the secret key ring.

For now the only way to accomplish that that I came across is, to
serialize the PGPSecretKeyRing to a byte array and deserialize it into a
PGPPublicKeyRing. Same procedure applies if I want to convert a key ring
into a key ring collection. However, this appears a little inefficient
to me.

Is there a better way to do this?

Greetings
Paul