* A "plain" socket implements these methods exactly as * described, without attempting to go through a firewall or proxy. * * @author unascribed * @since 1.0 */ public abstract class SocketImpl implements SocketOptions { /** * The actual Socket object. */ Socket socket = null; ServerSocket serverSocket = null; /** * The file descriptor object for this socket. */ protected FileDescriptor fd; /** * The IP address of the remote end of this socket. */ protected InetAddress address; /** * The port number on the remote host to which this socket is connected. */ protected int port; /** * The local port number to which this socket is connected. */ protected int localport; /** * Creates either a stream or a datagram socket. * * @param stream if {@code true}, create a stream socket; * otherwise, create a datagram socket. * @exception IOException if an I/O error occurs while creating the * socket. */ protected abstract void create(boolean stream) throws IOException; /** * Connects this socket to the specified port on the named host. * * @param host the name of the remote host. * @param port the port number. * @exception IOException if an I/O error occurs when connecting to the * remote host. */ protected abstract void connect(String host, int port) throws IOException; /** * Connects this socket to the specified port number on the specified host. * * @param address the IP address of the remote host. * @param port the port number. * @exception IOException if an I/O error occurs when attempting a * connection. */ protected abstract void connect(InetAddress address, int port) throws IOException; /** * Connects this socket to the specified port number on the specified host. * A timeout of zero is interpreted as an infinite timeout. The connection * will then block until established or an error occurs. * * @param address the Socket address of the remote host. * @param timeout the timeout value, in milliseconds, or zero for no timeout. * @exception IOException if an I/O error occurs when attempting a * connection. * @since 1.4 */ protected abstract void connect(SocketAddress address, int timeout) throws IOException; /** * Binds this socket to the specified local IP address and port number. * * @param host an IP address that belongs to a local interface. * @param port the port number. * @exception IOException if an I/O error occurs when binding this socket. */ protected abstract void bind(InetAddress host, int port) throws IOException; /** * Sets the maximum queue length for incoming connection indications * (a request to connect) to the {@code count} argument. If a * connection indication arrives when the queue is full, the * connection is refused. * * @param backlog the maximum length of the queue. * @exception IOException if an I/O error occurs when creating the queue. */ protected abstract void listen(int backlog) throws IOException; /** * Accepts a connection. * * @param s the accepted connection. * @exception IOException if an I/O error occurs when accepting the * connection. */ protected abstract void accept(SocketImpl s) throws IOException; /** * Returns an input stream for this socket. * * @return a stream for reading from this socket. * @exception IOException if an I/O error occurs when creating the * input stream. */ protected abstract InputStream getInputStream() throws IOException; /** * Returns an output stream for this socket. * * @return an output stream for writing to this socket. * @exception IOException if an I/O error occurs when creating the * output stream. */ protected abstract OutputStream getOutputStream() throws IOException; /** * Returns the number of bytes that can be read from this socket * without blocking. * * @return the number of bytes that can be read from this socket * without blocking. * @exception IOException if an I/O error occurs when determining the * number of bytes available. */ protected abstract int available() throws IOException; /** * Closes this socket. * * @exception IOException if an I/O error occurs when closing this socket. */ protected abstract void close() throws IOException; /** * Places the input stream for this socket at "end of stream". * Any data sent to this socket is acknowledged and then * silently discarded. * * If you read from a socket input stream after invoking this method on the * socket, the stream's {@code available} method will return 0, and its * {@code read} methods will return {@code -1} (end of stream). * * @exception IOException if an I/O error occurs when shutting down this * socket. * @see java.net.Socket#shutdownOutput() * @see java.net.Socket#close() * @see java.net.Socket#setSoLinger(boolean, int) * @since 1.3 */ protected void shutdownInput() throws IOException { throw new IOException("Method not implemented!"); } /** * Disables the output stream for this socket. * For a TCP socket, any previously written data will be sent * followed by TCP's normal connection termination sequence. * * If you write to a socket output stream after invoking * shutdownOutput() on the socket, the stream will throw * an IOException. * * @exception IOException if an I/O error occurs when shutting down this * socket. * @see java.net.Socket#shutdownInput() * @see java.net.Socket#close() * @see java.net.Socket#setSoLinger(boolean, int) * @since 1.3 */ protected void shutdownOutput() throws IOException { throw new IOException("Method not implemented!"); } /** * Returns the value of this socket's {@code fd} field. * * @return the value of this socket's {@code fd} field. * @see java.net.SocketImpl#fd */ protected FileDescriptor getFileDescriptor() { return fd; } /** * Returns the value of this socket's {@code address} field. * * @return the value of this socket's {@code address} field. * @see java.net.SocketImpl#address */ protected InetAddress getInetAddress() { return address; } /** * Returns the value of this socket's {@code port} field. * * @return the value of this socket's {@code port} field. * @see java.net.SocketImpl#port */ protected int getPort() { return port; } /** * Returns whether or not this SocketImpl supports sending * urgent data. By default, false is returned * unless the method is overridden in a sub-class * * @return true if urgent data supported * @see java.net.SocketImpl#address * @since 1.4 */ protected boolean supportsUrgentData () { return false; // must be overridden in sub-class } /** * Send one byte of urgent data on the socket. * The byte to be sent is the low eight bits of the parameter * @param data The byte of data to send * @exception IOException if there is an error * sending the data. * @since 1.4 */ protected abstract void sendUrgentData (int data) throws IOException; /** * Returns the value of this socket's {@code localport} field. * * @return the value of this socket's {@code localport} field. * @see java.net.SocketImpl#localport */ protected int getLocalPort() { return localport; } void setSocket(Socket soc) { this.socket = soc; } Socket getSocket() { return socket; } void setServerSocket(ServerSocket soc) { this.serverSocket = soc; } ServerSocket getServerSocket() { return serverSocket; } /** * Returns the address and port of this socket as a {@code String}. * * @return a string representation of this socket. */ public String toString() { return "Socket[addr=" + getInetAddress() + ",port=" + getPort() + ",localport=" + getLocalPort() + "]"; } void reset() throws IOException { address = null; port = 0; localport = 0; } /** * Sets performance preferences for this socket. * *
Sockets use the TCP/IP protocol by default. Some implementations * may offer alternative protocols which have different performance * characteristics than TCP/IP. This method allows the application to * express its own preferences as to how these tradeoffs should be made * when the implementation chooses from the available protocols. * *
Performance preferences are described by three integers
* whose values indicate the relative importance of short connection time,
* low latency, and high bandwidth. The absolute values of the integers
* are irrelevant; in order to choose a protocol the values are simply
* compared, with larger values indicating stronger preferences. Negative
* values represent a lower priority than positive values. If the
* application prefers short connection time over both low latency and high
* bandwidth, for example, then it could invoke this method with the values
* {@code (1, 0, 0)}. If the application prefers high bandwidth above low
* latency, and low latency above short connection time, then it could
* invoke this method with the values {@code (0, 1, 2)}.
*
* By default, this method does nothing, unless it is overridden in a
* a sub-class.
*
* @param connectionTime
* An {@code int} expressing the relative importance of a short
* connection time
*
* @param latency
* An {@code int} expressing the relative importance of low
* latency
*
* @param bandwidth
* An {@code int} expressing the relative importance of high
* bandwidth
*
* @since 1.5
*/
protected void setPerformancePreferences(int connectionTime,
int latency,
int bandwidth)
{
/* Not implemented yet */
}
/**
* Called to set a socket option.
*
* @param