IT. Expert System.

Direct Known Subclasses:

MulticastSocket

public class DatagramSocket
extends Object

See Also:

DatagramPacket, DatagramSocketImplFactory

• Constructor Summary

  Constructors

  Modifier	Constructor and Description
  	DatagramSocket() Constructs a UDP datagram socket which is bound to any available port on the localhost.
  protected	DatagramSocket(DatagramSocketImpl socketImpl) Constructs a new DatagramSocket using the specific datagram socket implementation socketImpl.
  	DatagramSocket(int aPort) Constructs a UDP datagram socket which is bound to the specific port aPort on the localhost.
  	DatagramSocket(int aPort, InetAddress addr) Constructs a UDP datagram socket which is bound to the specific local address addr on port aPort.
  	DatagramSocket(SocketAddress localAddr) Constructs a new DatagramSocket bound to the host/port specified by the SocketAddress localAddr or an unbound DatagramSocket if the SocketAddress is null.

• Method Summary

  Methods

  Modifier and Type	Method and Description
  void	bind(SocketAddress localAddr) Binds this socket to the local address and port specified by localAddr.
  void	close() Closes this UDP datagram socket and all possibly associated channels.
  void	connect(InetAddress address, int port) Connects this datagram socket to the specific address and port.
  void	connect(SocketAddress peer) Connects this datagram socket to the address and port specified by peer.
  void	disconnect() Disconnects this UDP datagram socket from the remote host.
  boolean	getBroadcast() Gets the state of the socket option SocketOptions.SO_BROADCAST.
  DatagramChannel	getChannel() Returns this socket's DatagramChannel, if one exists.
  FileDescriptor	getFileDescriptor$()
  InetAddress	getInetAddress() Gets the InetAddress instance representing the remote address to which this UDP datagram socket is connected.
  InetAddress	getLocalAddress() Gets the InetAddress instance representing the bound local address of this UDP datagram socket.
  int	getLocalPort() Gets the local port which this socket is bound to.
  SocketAddress	getLocalSocketAddress() Returns the SocketAddress this socket is bound to, or null for an unbound socket.
  int	getPort() Gets the remote port which this socket is connected to.
  int	getReceiveBufferSize() Returns this socket's receive buffer size.
  SocketAddress	getRemoteSocketAddress() Returns the SocketAddress this socket is connected to, or null for an unconnected socket.
  boolean	getReuseAddress() Gets the state of the socket option SocketOptions.SO_REUSEADDR.
  int	getSendBufferSize() Returns this socket's send buffer size.
  int	getSoTimeout() Gets the socket receive timeout.
  int	getTrafficClass() Returns this socket's SocketOptions.IP_TOS setting.
  boolean	isBound() Returns true if this socket is bound to a local address.
  boolean	isClosed() Gets the state of this socket.
  boolean	isConnected() Returns true if this datagram socket is connected to a remote address.
  void	receive(DatagramPacket pack) Receives a packet from this socket and stores it in the argument pack.
  void	send(DatagramPacket pack) Sends a packet over this socket.
  void	setBroadcast(boolean broadcast) Sets the socket option SocketOptions.SO_BROADCAST.
  static void	setDatagramSocketImplFactory(DatagramSocketImplFactory fac) Sets the socket implementation factory.
  void	setNetworkInterface(NetworkInterface netInterface) Sets the network interface used by this socket.
  void	setReceiveBufferSize(int size) Sets this socket's receive buffer size.
  void	setReuseAddress(boolean reuse) Sets the socket option SocketOptions.SO_REUSEADDR.
  void	setSendBufferSize(int size) Sets this socket's send buffer size.
  void	setSoTimeout(int timeout) Sets the read timeout in milliseconds for this socket.
  void	setTrafficClass(int value) Sets the SocketOptions.IP_TOS value for every packet sent by this socket.

  • Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

• Constructor Detail

  • DatagramSocket

    public DatagramSocket()
                   throws SocketException

    Constructs a UDP datagram socket which is bound to any available port on the localhost.

    Throws:

    SocketException - if an error occurs while creating or binding the socket.

  • DatagramSocket

    public DatagramSocket(int aPort)
                   throws SocketException

    Constructs a UDP datagram socket which is bound to the specific port aPort on the localhost. Valid values for aPort are between 0 and 65535 inclusive.

    Parameters:

    aPort - the port to bind on the localhost.

    Throws:

    SocketException - if an error occurs while creating or binding the socket.

  • DatagramSocket

    public DatagramSocket(int aPort,
                  InetAddress addr)
                   throws SocketException

    Constructs a UDP datagram socket which is bound to the specific local address addr on port aPort. Valid values for aPort are between 0 and 65535 inclusive.

    Parameters:

    aPort - the port to bind on the localhost.

    addr - the address to bind on the localhost.

    Throws:

    SocketException - if an error occurs while creating or binding the socket.

  • DatagramSocket

    protected DatagramSocket(DatagramSocketImpl socketImpl)

    Constructs a new DatagramSocket using the specific datagram socket implementation socketImpl. The created DatagramSocket will not be bound.

    Parameters:

    socketImpl - the DatagramSocketImpl to use.

  • DatagramSocket

    public DatagramSocket(SocketAddress localAddr)
                   throws SocketException

    Constructs a new DatagramSocket bound to the host/port specified by the SocketAddress localAddr or an unbound DatagramSocket if the SocketAddress is null.

    Parameters:

    localAddr - the local machine address and port to bind to.

    Throws:

    IllegalArgumentException - if the SocketAddress is not supported

    SocketException - if a problem occurs creating or binding the socket.

• Method Detail

  • close

    public void close()

    Closes this UDP datagram socket and all possibly associated channels.

  • disconnect

    public void disconnect()

    Disconnects this UDP datagram socket from the remote host. This method called on an unconnected socket does nothing.

  • getInetAddress

    public InetAddress getInetAddress()

    Gets the InetAddress instance representing the remote address to which this UDP datagram socket is connected.

    Returns:

    the remote address this socket is connected to or null if this socket is not connected.

  • getLocalAddress

    public InetAddress getLocalAddress()

    Gets the InetAddress instance representing the bound local address of this UDP datagram socket.

    Returns:

    the local address to which this socket is bound to or null if this socket is closed.

  • getLocalPort

    public int getLocalPort()

    Gets the local port which this socket is bound to.

    Returns:

    the local port of this socket or -1 if this socket is closed and 0 if it is unbound.

  • getPort

    public int getPort()

    Gets the remote port which this socket is connected to.

    Returns:

    the remote port of this socket. The return value -1 indicates that this socket is not connected.

  • getReceiveBufferSize

    public int getReceiveBufferSize()
                             throws SocketException

    Returns this socket's receive buffer size.

    Throws:

    SocketException

  • getSendBufferSize

    public int getSendBufferSize()
                          throws SocketException

    Returns this socket's send buffer size.

    Throws:

    SocketException

  • getSoTimeout

    public int getSoTimeout()
                     throws SocketException

    Gets the socket receive timeout.

    Throws:

    SocketException - if an error occurs while getting the option value.

  • receive

    public void receive(DatagramPacket pack)
                 throws IOException

    Receives a packet from this socket and stores it in the argument pack. All fields of pack must be set according to the data received. If the received data is longer than the packet buffer size it is truncated. This method blocks until a packet is received or a timeout has expired.

    Parameters:

    pack - the DatagramPacket to store the received data.

    Throws:

    IOException - if an error occurs while receiving the packet.

  • send

    public void send(DatagramPacket pack)
              throws IOException

    Sends a packet over this socket.

    Parameters:

    pack - the DatagramPacket which has to be sent.

    Throws:

    IOException - if an error occurs while sending the packet.

  • setNetworkInterface

    public void setNetworkInterface(NetworkInterface netInterface)
                             throws SocketException

    Sets the network interface used by this socket. Any packets sent via this socket are transmitted via the specified interface. Any packets received by this socket will come from the specified interface. Broadcast datagrams received on this interface will be processed by this socket. This corresponds to Linux's SO_BINDTODEVICE.

    Throws:

    SocketException

  • setSendBufferSize

    public void setSendBufferSize(int size)
                           throws SocketException

    Sets this socket's send buffer size.

    Throws:

    SocketException

  • setReceiveBufferSize

    public void setReceiveBufferSize(int size)
                              throws SocketException

    Sets this socket's receive buffer size.

    Throws:

    SocketException

  • setSoTimeout

    public void setSoTimeout(int timeout)
                      throws SocketException

    Sets the read timeout in milliseconds for this socket. This receive timeout defines the period the socket will block waiting to receive data before throwing an InterruptedIOException. The value 0 (default) is used to set an infinite timeout. To have effect this option must be set before the blocking method was called.

    Parameters:

    timeout - the timeout in milliseconds or 0 for no timeout.

    Throws:

    SocketException - if an error occurs while setting the option.

  • setDatagramSocketImplFactory

    public static void setDatagramSocketImplFactory(DatagramSocketImplFactory fac)
                                             throws IOException

    Sets the socket implementation factory. This may only be invoked once over the lifetime of the application. This factory is used to create a new datagram socket implementation.

    Parameters:

    fac - the socket factory to use.

    Throws:

    IOException - if the factory has already been set.

    See Also:

    DatagramSocketImplFactory

  • bind

    public void bind(SocketAddress localAddr)
              throws SocketException

    Binds this socket to the local address and port specified by localAddr. If this value is null any free port on a valid local address is used.

    Parameters:

    localAddr - the local machine address and port to bind on.

    Throws:

    IllegalArgumentException - if the SocketAddress is not supported

    SocketException - if the socket is already bound or a problem occurs during binding.

  • connect

    public void connect(SocketAddress peer)
                 throws SocketException

    Connects this datagram socket to the address and port specified by peer. Future calls to send(java.net.DatagramPacket) will use this as the default target, and receive(java.net.DatagramPacket) will only accept packets from this source.

    Throws:

    SocketException - if an error occurs.

  • connect

    public void connect(InetAddress address,
               int port)

    Connects this datagram socket to the specific address and port. Future calls to send(java.net.DatagramPacket) will use this as the default target, and receive(java.net.DatagramPacket) will only accept packets from this source.

    Beware: because it can't throw, this method silently ignores failures. Use connect(SocketAddress) instead.

  • isBound

    public boolean isBound()

    Returns true if this socket is bound to a local address. See bind(java.net.SocketAddress).

  • isConnected

    public boolean isConnected()

    Returns true if this datagram socket is connected to a remote address. See connect(java.net.SocketAddress).

  • getRemoteSocketAddress

    public SocketAddress getRemoteSocketAddress()

    Returns the SocketAddress this socket is connected to, or null for an unconnected socket.

  • getLocalSocketAddress

    public SocketAddress getLocalSocketAddress()

    Returns the SocketAddress this socket is bound to, or null for an unbound socket.

  • setReuseAddress

    public void setReuseAddress(boolean reuse)
                         throws SocketException

    Sets the socket option SocketOptions.SO_REUSEADDR. This option has to be enabled if more than one UDP socket wants to be bound to the same address. That could be needed for receiving multicast packets.

    There is an undefined behavior if this option is set after the socket is already bound.

    Parameters:

    reuse - the socket option value to enable or disable this option.

    Throws:

    SocketException - if the socket is closed or the option could not be set.

  • getReuseAddress

    public boolean getReuseAddress()
                            throws SocketException

    Gets the state of the socket option SocketOptions.SO_REUSEADDR.

    Returns:

    true if the option is enabled, false otherwise.

    Throws:

    SocketException - if the socket is closed or the option is invalid.

  • setBroadcast

    public void setBroadcast(boolean broadcast)
                      throws SocketException

    Sets the socket option SocketOptions.SO_BROADCAST. This option must be enabled to send broadcast messages.

    Parameters:

    broadcast - the socket option value to enable or disable this option.

    Throws:

    SocketException - if the socket is closed or the option could not be set.

  • getBroadcast

    public boolean getBroadcast()
                         throws SocketException

    Gets the state of the socket option SocketOptions.SO_BROADCAST.

    Returns:

    true if the option is enabled, false otherwise.

    Throws:

    SocketException - if the socket is closed or the option is invalid.

  • setTrafficClass

    public void setTrafficClass(int value)
                         throws SocketException

    Sets the SocketOptions.IP_TOS value for every packet sent by this socket.

    Throws:

    SocketException - if the socket is closed or the option could not be set.

  • getTrafficClass

    public int getTrafficClass()
                        throws SocketException

    Returns this socket's SocketOptions.IP_TOS setting.

    Throws:

    SocketException - if the socket is closed or the option is invalid.

  • isClosed

    public boolean isClosed()

    Gets the state of this socket.

    Returns:

    true if the socket is closed, false otherwise.

  • getChannel

    public DatagramChannel getChannel()

    Returns this socket's DatagramChannel, if one exists. A channel is available only if this socket wraps a channel. (That is, you can go from a channel to a socket and back again, but you can't go from an arbitrary socket to a channel.) In practice, this means that the socket must have been created by DatagramChannel.open().

  • getFileDescriptor$

    public final FileDescriptor getFileDescriptor$()