Why doesn't more Java code use PipedInputStream / PipedOutputStream?

Question

I\'ve discovered this idiom recently, and I am wondering if there is something I am missing. I\'ve never seen it used. Nearly all Java code I\'ve worked with in the wild fav

Answer 1

Here's a use case where pipes make sense:

Suppose you have a third party lib, such as an xslt mapper or crypto lib that has an interface like this: doSomething(inputStream, outputStream). And you do not want to buffer the result before sending over the wire. Apache and other clients disallow direct access to the wire outputstream. Closest you can get is obtaining the outputstream - at an offset, after headers are written - in a request entity object. But since this is under the hood, it's still not enough to pass an inputstream and outputstream to the third party lib. Pipes are a good solution to this problem.

Incidentally, I wrote an inversion of Apache's HTTP Client API [PipedApacheClientOutputStream] which provides an OutputStream interface for HTTP POST using Apache Commons HTTP Client 4.3.4. This is an example where Piped Streams might make sense.