Package java.net

Class DatagramSocketImpl

java.lang.Object

java.net.DatagramSocketImpl

All Implemented Interfaces:

SocketOptions

Direct Known Subclasses:

PlainDatagramSocketImpl

public abstract class DatagramSocketImpl
extends Object
implements SocketOptions

The abstract superclass for datagram and multicast socket implementations.

Field Summary

Fields

Modifier and Type	Field	Description
protected FileDescriptor	fd	File descriptor that is used to address this socket.
protected int	localPort	The number of the local port to which this socket is bound.

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_REUSEPORT, SO_SNDBUF, SO_TIMEOUT, TCP_NODELAY

Constructor Summary

Constructors

Constructor	Description
DatagramSocketImpl()	Constructs an unbound datagram socket implementation.

Method Summary

Modifier and Type	Method	Description
protected abstract void	bind(int port, InetAddress addr)	Binds the datagram socket to the given local host/port.
protected abstract void	close()	Closes this socket.
protected void	connect(InetAddress inetAddr, int port)	Connects this 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()	Disconnects this socket from the remote host.
protected FileDescriptor	getFileDescriptor()	Gets the FileDescriptor of this datagram socket, which is invalid if the socket is closed or not bound.
protected int	getLocalPort()	Returns the local port to which this socket is bound.
protected abstract int	getTimeToLive()	Gets the time-to-live (TTL) for multicast packets sent on this socket.
protected abstract byte	getTTL()	Deprecated. Use getTimeToLive() instead.
protected abstract void	join(InetAddress addr)	Adds this socket to the multicast group addr.
protected abstract void	joinGroup(SocketAddress addr, NetworkInterface netInterface)	Adds this socket to the multicast group addr.
protected abstract void	leave(InetAddress addr)	Removes this socket from the multicast group addr.
protected abstract void	leaveGroup(SocketAddress addr, NetworkInterface netInterface)	Removes this socket from the multicast group addr.
protected void	onBind(InetAddress localAddress, int localPort)	Initialize the bind() state.
protected void	onClose()	Initialize the closed state.
protected void	onConnect(InetAddress remoteAddress, int remotePort)	Initialize the connect() state.
protected void	onDisconnect()	Initialize the disconnected state.
protected abstract int	peek(InetAddress sender)	Peeks at the incoming packet to this socket and returns the address of the sender.
protected abstract int	peekData(DatagramPacket pack)	Receives data into the supplied datagram packet by peeking.
protected abstract void	receive(DatagramPacket pack)	Receives data and stores it in the supplied datagram packet pack.
protected abstract void	send(DatagramPacket pack)	Sends the given datagram packet pack.
protected abstract void	setTimeToLive(int ttl)	Sets the time-to-live (TTL) option for multicast packets sent on this socket.
protected abstract void	setTTL(byte ttl)	Deprecated. Use setTimeToLive(int) instead.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.net.SocketOptions

getOption, setOption

Field Detail

fd

protected FileDescriptor fd

File descriptor that is used to address this socket.

localPort

protected int localPort

The number of the local port to which this socket is bound.

Constructor Detail

DatagramSocketImpl

public DatagramSocketImpl()

Constructs an unbound datagram socket implementation.

Method Detail

bind

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

Binds the datagram socket to the given local host/port. Sockets must be bound prior to attempting to send or receive data.

Parameters:

port - the port on the local host to bind to.

addr - the address on the multihomed local host to bind to.

Throws:

SocketException - if an error occurs while binding, for example, if the port has been already bound.

close

protected abstract void close()

Closes this socket.

create

protected abstract void create()
                        throws SocketException

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

Throws:

SocketException - if an error occurs while creating the socket.

getFileDescriptor

protected FileDescriptor getFileDescriptor()

Gets the FileDescriptor of this datagram socket, which is invalid if the socket is closed or not bound.

Returns:

the current file descriptor of this socket.

getLocalPort

protected int getLocalPort()

Returns the local port to which this socket is bound.

getTTL

@Deprecated
protected abstract byte getTTL()
                        throws IOException

Deprecated.

Use getTimeToLive() instead.

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

Returns:

the time-to-live option as a byte value.

Throws:

IOException - if an error occurs while getting the time-to-live option value.

See Also:

getTimeToLive()

getTimeToLive

protected abstract int getTimeToLive()
                              throws IOException

Gets the time-to-live (TTL) for multicast packets sent on this socket. The TTL option defines how many routers a packet may be pass before it is discarded.

Returns:

the time-to-live option as an integer value.

Throws:

IOException - if an error occurs while getting the time-to-live option value.

join

protected abstract void join(InetAddress addr)
                      throws IOException

Adds this socket to the multicast group addr. A socket must join a group before being able to receive data. Further, a socket may be a member of multiple groups but may join any group only once.

Parameters:

addr - the multicast group to which this socket has to be joined.

Throws:

IOException - if an error occurs while joining the specified multicast group.

joinGroup

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

Adds this socket to the multicast group addr. A socket must join a group before being able to receive data. Further, a socket may be a member of multiple groups but may join any group only once.

Parameters:

addr - the multicast group to which this socket has to be joined.

netInterface - the local network interface which will receive the multicast datagram packets.

Throws:

IOException - if an error occurs while joining the specified multicast group.

leave

protected abstract void leave(InetAddress addr)
                       throws IOException

Removes this socket from the multicast group addr.

Parameters:

addr - the multicast group to be left.

Throws:

IOException - if an error occurs while leaving the group or no multicast address was assigned.

leaveGroup

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

Removes this socket from the multicast group addr.

Parameters:

addr - the multicast group to be left.

netInterface - the local network interface on which this socket has to be removed.

Throws:

IOException - if an error occurs while leaving the group.

peek

protected abstract int peek(InetAddress sender)
                     throws IOException

Peeks at the incoming packet to this socket and returns the address of the sender. The method will block until a packet is received or timeout expires.

Parameters:

sender - the origin address of a packet.

Returns:

the address of sender as an integer value.

Throws:

IOException - if an error or a timeout occurs while reading the address.

receive

protected abstract void receive(DatagramPacket pack)
                         throws IOException

Receives data and stores it in the supplied datagram packet pack. This call will block until either data has been received or, if a timeout is set, the timeout has expired. If the timeout expires an InterruptedIOException is thrown.

Parameters:

pack - the datagram packet container to fill in the received data.

Throws:

IOException - if an error or timeout occurs while receiving data.

send

protected abstract void send(DatagramPacket pack)
                      throws IOException

Sends the given datagram packet pack. The packet contains the data and the address and port information of the target host as well.

Parameters:

pack - the datagram packet to be sent.

Throws:

IOException - if an error occurs while sending the packet.

setTimeToLive

protected abstract void setTimeToLive(int ttl)
                               throws IOException

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

Parameters:

ttl - the time-to-live option value. Valid values are 0 < ttl <= 255.

Throws:

IOException - if an error occurs while setting the option.

setTTL

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

Deprecated.

Use setTimeToLive(int) instead.

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

Parameters:

ttl - the time-to-live option value. Valid values are 0 < ttl <= 255.

Throws:

IOException - if an error occurs while setting the option.

See Also:

setTimeToLive(int)

connect

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

Connects this socket to the specified remote address and port.

Parameters:

inetAddr - the address of the target host which has to be connected.

port - the port on the target host which has to be connected.

Throws:

SocketException - if the datagram socket cannot be connected to the specified remote address and port.

disconnect

protected void disconnect()

Disconnects this socket from the remote host.

peekData

protected abstract int peekData(DatagramPacket pack)
                         throws IOException

Receives data into the supplied datagram packet by peeking. The data is not removed from socket buffer and can be received again by another peekData() or receive() call. This call blocks until either data has been received or, if a timeout is set, the timeout has been expired.

Parameters:

pack - the datagram packet used to store the data.

Returns:

the port the packet was received from.

Throws:

IOException - if an error occurs while peeking at the data.

onBind

protected void onBind(InetAddress localAddress,
                      int localPort)

Initialize the bind() state.

onConnect

protected void onConnect(InetAddress remoteAddress,
                         int remotePort)

Initialize the connect() state.

onDisconnect

protected void onDisconnect()

Initialize the disconnected state.

onClose

protected void onClose()

Initialize the closed state.