SocketInputStream(AbstractPlainSocketImpl impl) throws IOException 
{
        super(impl.getFileDescriptor());
        this.impl = impl;
        socket = impl.getSocket();
}

Creates a new SocketInputStream. Can only be called by a Socket. This method needs to hang on to the owner Socket so that the fd will not be closed.

Parameters:

impl - the implemented socket input stream

 public int available() throws IOException 
{
        return impl.available();
}

Returns the number of bytes that can be read without blocking.

 public  void close() throws IOException 
{
        // Prevent recursion. See BugId 4484411
        if (closing)
            return;
        closing = true;
        if (socket != null) {
            if (!socket.isClosed())
                socket.close();
        } else
            impl.close();
        closing = false;
}

 protected  void finalize() 
{

}

Overrides finalize, the fd is closed by the Socket.

 public final FileChannel getChannel() 
{
        return null;
}

Returns the unique FileChannel object associated with this file input stream.
The getChannel method of SocketInputStream returns null since it is a socket based stream.

 public int read() throws IOException 
{
        if (eof) {
            return -1;
        }
        temp = new byte[1];
        int n = read(temp, 0, 1);
        if (n < = 0) {
            return -1;
        }
        return temp[0] & 0xff;
}

Reads a single byte from the socket.

 public int read(byte[] b) throws IOException 
{
        return read(b, 0, b.length);
}

Reads into a byte array data from the socket.

 public int read(byte[] b,
    int off,
    int length) throws IOException 
{
        return read(b, off, length, impl.getTimeout());
}

Reads into a byte array b at offset off, length bytes of data.

 int read(byte[] b,
    int off,
    int length,
    int timeout) throws IOException 
{
        int n;
        // EOF already encountered
        if (eof) {
            return -1;
        }
        // connection reset
        if (impl.isConnectionReset()) {
            throw new SocketException("Connection reset");
        }
        // bounds check
        if (length < = 0 || off <  0 || off + length  > b.length) {
            if (length == 0) {
                return 0;
            }
            throw new ArrayIndexOutOfBoundsException();
        }
        boolean gotReset = false;
        // acquire file descriptor and do the read
        FileDescriptor fd = impl.acquireFD();
        try {
            n = socketRead0(fd, b, off, length, timeout);
            if (n  > 0) {
                return n;
            }
        } catch (ConnectionResetException rstExc) {
            gotReset = true;
        } finally {
            impl.releaseFD();
        }
        /*
         * We receive a "connection reset" but there may be bytes still
         * buffered on the socket
         */
        if (gotReset) {
            impl.setConnectionResetPending();
            impl.acquireFD();
            try {
                n = socketRead0(fd, b, off, length, timeout);
                if (n  > 0) {
                    return n;
                }
            } catch (ConnectionResetException rstExc) {
            } finally {
                impl.releaseFD();
            }
        }
        /*
         * If we get here we are at EOF, the socket has been closed,
         * or the connection has been reset.
         */
        if (impl.isClosedOrPending()) {
            throw new SocketException("Socket closed");
        }
        if (impl.isConnectionResetPending()) {
            impl.setConnectionReset();
        }
        if (impl.isConnectionReset()) {
            throw new SocketException("Connection reset");
        }
        eof = true;
        return -1;
}

  void setEOF(boolean eof) 
{
        this.eof = eof;
}

 public long skip(long numbytes) throws IOException 
{
        if (numbytes < = 0) {
            return 0;
        }
        long n = numbytes;
        int buflen = (int) Math.min(1024, n);
        byte data[] = new byte[buflen];
        while (n  > 0) {
            int r = read(data, 0, (int) Math.min((long) buflen, n));
            if (r <  0) {
                break;
            }
            n -= r;
        }
        return numbytes - n;
}

Skips n bytes of input.