Hiding lines based on a regexp

[David Vanderschel]

Could someone please point me to a mechanism that
would allow me to temporarily hide from display
certain lines in a file based on a matching regular
expression?  There is somewhat similar functionality
with hide-ifdef-mode.  However, I want something less
clever and more general.

What I have in mind is to suppress lines I have
inserted into a program for debugging purpose, but
which lines can make examining the code more
difficult.  For example, when coding in java, there
are times when I would like to hide lines that match
"assert" or "system.out.println".

Though I usually manage to squeeze my debugging
statements onto a single line, it would be even better
if the mechanism could recognize that a matching
language statement was spread over multiple lines.

Thanks,
  David V.