NIO BufferedInputStream

Question

I know I can extract the data from a NIO socket by reading the channel, but I was trying a different approach and ran across something strange.
When I take the socket from a NIO channel and attach a BufferedInputStream to it as with a normal socket, and then try to read from that every time the selector announces that data is ready - it will tell me there is no data to be read if I call available() - and if I try to read it won't return any. It seems almost as if the channel has already taken the data from the socket and buffered it into itself?
I'm just wondering if this is expected behavior, or if I am actually doing something wrong. (I know it's a strange approach - I'm just wondering if theoretically it should work or not)

Answer 1

Here is the relevant code from two different classes from a much larger project - I renamed and removed a few things so if something doesn't make sense that's probably why.
So, in this example tmpTO.ReadBufferedData(); is called and when it gets to System.out.println("bytesavail:'" + bytesAvail + "'"); it prints out bytesavail: 0
private void AddNewSocket(SocketChannel newSC)
     SelectionKey tmpSK = null;
     try
          newSC.configureBlocking(false);
          newSC.socket().setTcpNoDelay(true);
          tmpSK = newSC.register(mySelector, SelectionKey.OP_READ);
     } catch (IOException ioe) {}
     DataTestObj tmpTO = new DataTestObj(newSC.socket());
     tmpSK.attach(tmpTO);
* Start checking our sockets for incoming data
public void run()
     boolean listening = true;
     try
          // initialize our nio
          mySelector = SelectorProvider.provider().openSelector();
     } catch (IOException ioe) {}
     new Thread(NS).start();
     Thread.yield();
     while (listening)
          if (socketQueue.size() > 0)
               // if we have sockets waiting to be added...
               Iterator<SocketChannel> LI = socketQueue.iterator();
               while (LI.hasNext())
                    AddNewSocketFinal(LI.next());
                    LI.remove();
          try
               if (mySelector.select(2000) > 0)
                    Iterator LI = mySelector.selectedKeys().iterator();
                    while (LI.hasNext())
                         System.out.println("incoming sock data");
                         SelectionKey tmpSK = (SelectionKey)LI.next();
                         Object tmpObj = tmpSK.attachment();
                         UserObject tmpUO = null;
                         DataTestObj tmpTO = null;
                         try
                              tmpTO = (DataTestObj)tmpObj;
                         } catch (ClassCastException cce) {}
                         String tmpStr = "";
                         if (tmpSK.isReadable())
                              // handle any available data
                              tmpTO.ReadBufferedData();
                              tmpStr = tmpTO.StorePacket();
                              while (tmpStr.length() > 0)
                                   // do stuff with the packet data...
          } catch (IOException ioe) {}
public class DataTestObj
     Socket mySock = null;
     BufferedOutputStream bos = null;
     BufferedInputStream bis = null;
     String PacketData = "";
     public DataTestObj(Socket sock)
          mySock = sock;
          try
               bos = new BufferedOutputStream(mySock.getOutputStream());
          catch (IOException ioe) {}
          try
               bis = new BufferedInputStream(mySock.getInputStream());
          catch (IOException ioe) {}
      * Read all the data from the socket
     public void ReadBufferedData()
          System.out.println("reading buffer");
          int bytesAvail = 0;
          int bytesRead = 0;
          int myRead = 0;
          byte[] ByteArr = new byte[1024];
          try
               bytesAvail = bis.available();
          catch (IOException ioe)
               System.out.println("bis avail err?:'" + ioe.toString() + "'");
          System.out.println("bytesavail:'" + bytesAvail + "'");
          while (bytesRead < bytesAvail)
               try
                    myRead = bis.read(ByteArr);
               catch (IOException e)
                    System.out.println("bis read err?:'" + e.toString() + "'");
                    myRead = 0;
               System.out.println("bytesread:'" + myRead + "'");
               if (myRead > 0)
                    try
                         PacketData += new String(ByteArr,0,myRead,"ISO-8859-1");
                         System.out.println("new pd len:'" + PacketData.length() + "'");
                    } catch (IOException e) {}
                    bytesRead += myRead;
               else if (myRead == -1)
                    break;
}