alternatives with ad hoc installation

[ChadDavis <chadmichaeldavis@gmail.com>]

I'm installing, by hand, a java7 distribution that doesn't exist in
the repositories.  Is it feasible to use the alternatives mechanism to
work with ad hoc installations like this?  In other words, I've
"installed" the java 7 jdk into /usr/local/jdk1.7.0.

I just want to check whether it's completely whacky, or hacky, to
pursue the path of using the alternatives mechanism with something
like this.  For instance, maybe it only works with installed packages
. . .

I'm basically look for a red light or green light on the notion of
investigating this solution further.