Re: Why should close() close the underlying stream?

From:

Eric Sosman <esosman@ieee-dot-org.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 23 Oct 2007 22:02:01 -0400

Message-ID:

<zK6dndF2UPk1OoPanZ2dnUVZ_gKdnZ2d@comcast.com>

Xiao Ma wrote:

A stream may have an underlying stream. For example,
FileOutputStream fos = new FileOutputStream("foo");
BufferedOutputStream bos = new BufferedOutputStream(fos);
fos is the underlying stream for bos.

Now if I call bos.close(), it will also close its underlying stream.
Why should the underlying stream be closed? I can think of some cases
where I want to continue to write to the underlying output stream
after I close the "outer" output stream.
[...]

The people who designed java.io apparently felt that
such cases were a small minority, and chose to simplify
matters for what they considered the much more common case.

If you need the "one at a time" discipline, you can
get it without much work. Just extend FileOutputStream (or
whatever) with a class of your own that inherits almost all
its methods from the superclass, but overrides close() and
ignores it. If desired you could add a reallyClose() method
that forwards to super.close(), and/or a getActualStream()
method that returns the superclass instance.

--
Eric Sosman
esosman@ieee-dot-org.invalid