java.net
Class DatagramSocketImpl

java.lang.Object
  java.net.DatagramSocketImpl

All Implemented Interfaces:

SocketOptions

public abstract class DatagramSocketImpl
extends Object
implements SocketOptions

The abstract superclass of datagram & multicast socket implementations.

Field Summary

protected FileDescriptor	fd
protected int	localPort

Fields inherited from interface java.net.SocketOptions

IP_MULTICAST_IF, IP_MULTICAST_IF2, IP_MULTICAST_LOOP, IP_TOS, SO_BINDADDR, SO_BROADCAST, SO_KEEPALIVE, SO_LINGER, SO_OOBINLINE, SO_RCVBUF, SO_REUSEADDR, SO_SNDBUF, SO_TIMEOUT, TCP_NODELAY

Constructor Summary

DatagramSocketImpl()
Constructs an unbound datagram socket implementation.

Method Summary

protected abstract void	bind(int port, InetAddress addr) Bind the datagram socket to the nominated localhost/port.
protected abstract void	close() Close the socket.
protected void	connect(InetAddress inetAddr, int port) Connect the socket to the specified remote address and port.
protected abstract void	create() This method allocates the socket descriptor in the underlying operating system.
protected void	disconnect() Disconnect the socket from the remote address and port.
protected FileDescriptor	getFileDescriptor() Answer the FileDescriptor, which will be invalid if the socket is closed or not bound.
(package private) InetAddress	getLocalAddress() Answer the local address to which the socket is bound.
protected int	getLocalPort() Answer the local port.
abstract Object	getOption(int optID) Answer the nominated socket option.
protected abstract int	getTimeToLive() Answer the time-to-live (TTL) for multicast packets sent on this socket.
protected abstract byte	getTTL() Deprecated. Replaced by getTimeToLive()
protected abstract void	join(InetAddress addr) Add this socket to the multicast group.
protected abstract void	joinGroup(SocketAddress addr, NetworkInterface netInterface) Add this socket to the multicast group.
protected abstract void	leave(InetAddress addr) Remove the socket from the multicast group.
protected abstract void	leaveGroup(SocketAddress addr, NetworkInterface netInterface) Remove the socket from the multicast group.
protected abstract int	peek(InetAddress sender) Peek at the incoming packet to this socket and answer the sender's address into sender.
protected abstract int	peekData(DatagramPacket pack) Receive data into the supplied datagram packet by peeking.
protected abstract void	receive(DatagramPacket pack) Receive data into the supplied datagram packet.
protected abstract void	send(DatagramPacket pack) Sends the supplied datagram packet.
abstract void	setOption(int optID, Object val) Set the nominated socket option.
protected abstract void	setTimeToLive(int ttl) Set the time-to-live (TTL) for multicast packets sent on this socket.
protected abstract void	setTTL(byte ttl) Deprecated. Replaced by setTimeToLive(int)

Methods inherited from class java.lang.Object

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

Field Detail

fd

protected FileDescriptor fd

localPort

protected int localPort

Constructor Detail

DatagramSocketImpl

public DatagramSocketImpl()

Constructs an unbound datagram socket implementation.

Method Detail

bind

protected abstract void bind(int port,
                             InetAddress addr)
                      throws SocketException

Bind the datagram socket to the nominated localhost/port. Sockets must be bound prior to attempting to send or receive data.

Parameters:

port - the port on the localhost to bind

addr - the address on the multihomed localhost to bind

Throws:

SocketException - if an error occurred during bind, such as if the port was already bound

close

protected abstract void close()

Close the socket.

create

protected abstract void create()
                        throws SocketException

This method allocates the socket descriptor in the underlying operating system.

Throws:

SocketException

getFileDescriptor

protected FileDescriptor getFileDescriptor()

Answer the FileDescriptor, which will be invalid if the socket is closed or not bound.

Returns:

FileDescriptor the socket file descriptor

getLocalAddress

InetAddress getLocalAddress()

Answer the local address to which the socket is bound.

Returns:

InetAddress the local address to which the socket is bound.

getLocalPort

protected int getLocalPort()

Answer the local port. If the socket was bound to any available port, as flagged by a localPort value of -1, query the IP stack.

Returns:

int the local port to which the socket is bound.

getOption

public abstract Object getOption(int optID)
                          throws SocketException

Answer the nominated socket option.

Specified by:

getOption in interface SocketOptions

Parameters:

optID - the socket option to retrieve

Returns:

Object the option value

Throws:

SocketException - thrown if an error occurs while accessing the option

getTTL

@Deprecated
protected abstract byte getTTL()
                        throws IOException

Deprecated. Replaced by getTimeToLive()

Answer the time-to-live (TTL) for multicast packets sent on this socket.

Returns:

java.net.InetAddress

Throws:

IOException - The exception description.

See Also:

getTimeToLive()

getTimeToLive

protected abstract int getTimeToLive()
                              throws IOException

Answer the time-to-live (TTL) for multicast packets sent on this socket.

Returns:

int

Throws:

IOException - The exception description.

join

protected abstract void join(InetAddress addr)
                      throws IOException

Add this socket to the multicast group. A socket must join a group before data may be received. A socket may be a member of multiple groups but may join any group once.

Parameters:

addr - the multicast group to be joined

Throws:

IOException - may be thrown while joining a group

joinGroup

protected abstract void joinGroup(SocketAddress addr,
                                  NetworkInterface netInterface)
                           throws IOException

Add this socket to the multicast group. A socket must join a group before data may be received. A socket may be a member of multiple groups but may join any group once.

Parameters:

addr - the multicast group to be joined

netInterface - the network interface on which the addresses should be dropped

Throws:

IOException - may be thrown while joining a group

leave

protected abstract void leave(InetAddress addr)
                       throws IOException

Remove the socket from the multicast group.

Parameters:

addr - the multicast group to be left

Throws:

IOException - May be thrown while leaving the group

leaveGroup

protected abstract void leaveGroup(SocketAddress addr,
                                   NetworkInterface netInterface)
                            throws IOException

Remove the socket from the multicast group.

Parameters:

addr - the multicast group to be left

netInterface - the network interface on which the addresses should be dropped

Throws:

IOException - May be thrown while leaving the group

peek

protected abstract int peek(InetAddress sender)
                     throws IOException

Peek at the incoming packet to this socket and answer the sender's address into sender. The method will block until a packet is received or timeout expires and returns the sender's port.

Throws:

IOException - if a read error or timeout occurs

receive

protected abstract void receive(DatagramPacket pack)
                         throws IOException

Receive data into the supplied datagram packet. This call will block until either data is received or, if a timeout is set, the timeout expires. If the timeout expires, the InterruptedIOException is thrown.

Throws:

IOException - if a read error or timeout occurs

send

protected abstract void send(DatagramPacket pack)
                      throws IOException

Sends the supplied datagram packet. The packet contains the destination host & port.

Parameters:

pack - DatagramPacket to send

Throws:

IOException - if a write error occurs

setOption

public abstract void setOption(int optID,
                               Object val)
                        throws SocketException

Set the nominated socket option.

Specified by:

setOption in interface SocketOptions

Parameters:

optID - the socket option to set

val - the option value

Throws:

SocketException - thrown if an error occurs while setting the option

setTimeToLive

protected abstract void setTimeToLive(int ttl)
                               throws IOException

Set the time-to-live (TTL) for multicast packets sent on this socket.

Parameters:

ttl - the time-to-live, 0 < ttl <= 255

Throws:

IOException - The exception thrown while setting the TTL

setTTL

@Deprecated
protected abstract void setTTL(byte ttl)
                        throws IOException

Deprecated. Replaced by setTimeToLive(int)

Set the time-to-live (TTL) for multicast packets sent on this socket.

Parameters:

ttl - the time-to-live, 0 < ttl <= 255

Throws:

IOException - The exception thrown while setting the TTL

See Also:

setTimeToLive(int)

connect

protected void connect(InetAddress inetAddr,
                       int port)
                throws SocketException

Connect the socket to the specified remote address and port.

Parameters:

inetAddr - the remote address

port - the remote port

Throws:

SocketException - possibly thrown, if the datagram socket cannot be connected to the specified remote address and port

disconnect

protected void disconnect()

Disconnect the socket from the remote address and port.

peekData

protected abstract int peekData(DatagramPacket pack)
                         throws IOException

Receive data into the supplied datagram packet by peeking. The data is not removed and will be received by another peekData() or receive() call. This call will block until either data is received or, if a timeout is set, the timeout expires.

Parameters:

pack - the DatagramPacket used to store the data

Returns:

the port the packet was received from

Throws:

IOException - if an error occurs