I'm faced with a bunch of build.xml files in several directories,
all of them define a certain target (say: T). The definition of
this target in all these build files are structurally nearly the same.
Their implementations differ only in small details, say, a different
value for some filename etc. During one build, all these targets are
executed by recursive calls of Ant.

Maintaining this is a nightmare, because every change of logic has to
be repeated in every build file, so I'm looking for away to have
only one copy of them.

Using an ENTITY declaration in the DOCTYPE and including these repeated
parts with &... does not work, because they are not completely identical.
Using properties as parameters for the differing bits does not work
either, because I can not change a property as soon as it is set once.

Of course I could write a new Ant task in Java, and pass the differing
values as attributes, but this seems to be an overkill for such a
seemingly simple problem.

Any ideas?

Ronald