Input and Output Stream Pipe in Java

Question

Does anyone have any good suggestions for creating a Pipe object in Java which is both an InputStream and and OutputStream since Java does not have multiple inherit

Answer 1

You can't create a class which derives both from InputStream and OutputStream because these aren't interfaces and they have common methods and Java doesn't allow multiple inheritance (the compiler doesn't know whether to call InputStream.close() or OutputStream.close() if you call close() on your new object).

The other problem is the buffer. Java wants to allocate a static buffer for the data (which doesn't change). This means when you use the `java.io.PipedXxxStream', the writing data to it will eventually block unless you use two different threads.

So the answer from Apocalisp is correct: You must write a copy loop.

I suggest that you include Apache's commons-io in your project which contains many helper routines just for tasks like this (copy data between streams, files, strings and all combinations thereof).