What the Point of SharedInputStream? I can share any InputStream!

Question

I made an InputStream called: MIMEInputStream which is a subclass of FilterInputStream. It allows me to read by line, simply by saving what it reads in a local buffer and looking for every occurrence of \n or \r\n. then returning what it found. I did a test where I used this for the first 3 lines of an input stream, then switched over to a DataInputStream and was able to read ALL data from that point onward. As far as I can tell, that's all SharedInputStreams do anyways. Yes?
My class is instantiated:
MIMEInputStream mis = new MIMEInputStream( new FileInputStream("d:\\test.mime");then when ready to switch over, i use:
DataInputStream dis = new DataInputStream(mis);and it works! So please tell me what Shared does over this?

Answer 1

I made an InputStream called: MIMEInputStream which is
a subclass of FilterInputStream. It allows me to read
by line, simply by saving what it reads in a local
buffer and looking for every occurrence of \n or \r\n.
then returning what it found. I did a test where I
used this for the first 3 lines of an input stream,
then switched over to a DataInputStream and was able
to read ALL data from that point onward. As far as I
can tell, that's all SharedInputStreams do anyways.
Yes?
My class is instantiated:
MIMEInputStream mis = new MIMEInputStream( new
FileInputStream("d:\\test.mime");then when ready to switch over, i use:
DataInputStream dis = new DataInputStream(mis);and it works! So please tell me what Shared does over
this?i tied something similar to your example with sockets once...
the results were unpleasant.
so i guess it depends on the kind of stream you are using. so i would suggest that the shared one is one that gives the desired functionality independent of the underlying stream source