java.net

Class DatagramSocketImpl

java.lang.Object

java.net.DatagramSocketImpl

All Implemented Interfaces:

SocketOptions

public abstract class DatagramSocketImpl
extends Object
implements SocketOptions

This abstract class models a datagram socket implementation. An actual implementation class would implement these methods, probably via redirecting them to native code.

Written using on-line Java Platform 1.2 API Specification, as well as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).

Status: Believed complete and correct.

Since:

1.1

Field Summary

Fields

Modifier and Type	Field and Description
protected FileDescriptor	fd The FileDescriptor object for this object.
protected int	localPort 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_SNDBUF, SO_TIMEOUT, TCP_NODELAY

Constructor Summary

Constructors

Constructor and Description
DatagramSocketImpl() Default, no-argument constructor for subclasses to call.

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract void	bind(int lport, InetAddress laddr) This method binds the socket to the specified local port and address.
protected abstract void	close() This methods closes the socket
protected void	connect(InetAddress address, int port) Connects the socket to a host specified by address and port.
protected abstract void	create() Creates a new datagram socket.
protected void	disconnect() Disconnects the socket.
protected FileDescriptor	getFileDescriptor() Returns the FileDescriptor for this socket
protected int	getLocalPort() Returns the local port this socket is bound to
protected abstract int	getTimeToLive() This method returns the current Time to Live (TTL) setting on this socket.
protected abstract byte	getTTL() Deprecated. // FIXME: when ?
protected abstract void	join(InetAddress inetaddr) Causes this socket to join the specified multicast group
protected abstract void	joinGroup(SocketAddress mcastaddr, NetworkInterface netIf) Causes this socket to join the specified multicast group on a specified device
protected abstract void	leave(InetAddress inetaddr) Causes the socket to leave the specified multicast group.
protected abstract void	leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf) Leaves a multicast group
protected abstract int	peek(InetAddress i) Takes a peek at the next packet received in order to retrieve the address of the sender
protected abstract int	peekData(DatagramPacket p) Takes a peek at the next packet received.
protected abstract void	receive(DatagramPacket p) Receives a packet of data from the network Will block until a packet arrives.
protected abstract void	send(DatagramPacket p) Transmits the specified packet of data to the network.
protected abstract void	setTimeToLive(int ttl) Sets the Time to Live (TTL) setting on this socket to the specified value.
protected abstract void	setTTL(byte ttl) Deprecated.

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

localPort

protected int localPort

The local port to which this socket is bound

fd

protected FileDescriptor fd

The FileDescriptor object for this object.

Constructor Detail

DatagramSocketImpl

public DatagramSocketImpl()

Default, no-argument constructor for subclasses to call.

Method Detail

bind

protected abstract void bind(int lport,
        InetAddress laddr)
                      throws SocketException

This method binds the socket to the specified local port and address.

Parameters:

lport - The port number to bind to

laddr - The address to bind to

Throws:

SocketException - If an error occurs

close

protected abstract void close()

This methods closes the socket

create

protected abstract void create()
                        throws SocketException

Creates a new datagram socket.

Throws:

SocketException - If an error occurs

peek

protected abstract int peek(InetAddress i)
                     throws IOException

Takes a peek at the next packet received in order to retrieve the address of the sender

Parameters:

i - The InetAddress to fill in with the information about the sender if the next packet

Returns:

The port number of the sender of the packet

Throws:

IOException - If an error occurs

PortUnreachableException - May be thrown if the socket is connected to a currently unreachable destination. Note, there is no guarantee that the exception will be thrown.

peekData

protected abstract int peekData(DatagramPacket p)
                         throws IOException

Takes a peek at the next packet received. This packet is not consumed. With the next peekData/receive operation this packet will be read again.

Parameters:

p - The DatagramPacket to fill in with the data sent.

Returns:

The port number of the sender of the packet.

Throws:

IOException - If an error occurs

PortUnreachableException - May be thrown if the socket is connected to a currently unreachable destination. Note, there is no guarantee that the exception will be thrown.

Since:

1.4

send

protected abstract void send(DatagramPacket p)
                      throws IOException

Transmits the specified packet of data to the network. The destination host and port should be encoded in the packet.

Parameters:

p - The packet to send

Throws:

IOException - If an error occurs

PortUnreachableException - May be thrown if the socket is connected to a currently unreachable destination. Note, there is no guarantee that the exception will be thrown.

receive

protected abstract void receive(DatagramPacket p)
                         throws IOException

Receives a packet of data from the network Will block until a packet arrives. The packet info in populated into the passed in DatagramPacket object.

Parameters:

p - A place to store the incoming packet.

Throws:

IOException - If an error occurs

PortUnreachableException - May be thrown if the socket is connected to a currently unreachable destination. Note, there is no guarantee that the exception will be thrown.

connect

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

Connects the socket to a host specified by address and port.

Parameters:

address - The InetAddress of the host to connect to

port - The port number of the host to connect to

Throws:

SocketException - If an error occurs

Since:

1.4

disconnect

protected void disconnect()

Disconnects the socket.

Since:

1.4

setTTL

protected abstract void setTTL(byte ttl)
                        throws IOException

Deprecated.

Sets the Time to Live (TTL) setting on this socket to the specified value. Use setTimeToLive(int) instead.

Parameters:

ttl - The new Time to Live value

Throws:

IOException - If an error occurs

getTTL

protected abstract byte getTTL()
                        throws IOException

Deprecated. // FIXME: when ?

This method returns the current Time to Live (TTL) setting on this socket. Use getTimeToLive() instead.

Returns:

the current time-to-live

Throws:

IOException - If an error occurs

setTimeToLive

protected abstract void setTimeToLive(int ttl)
                               throws IOException

Sets the Time to Live (TTL) setting on this socket to the specified value.

Parameters:

ttl - The new Time to Live value

Throws:

IOException - If an error occurs

getTimeToLive

protected abstract int getTimeToLive()
                              throws IOException

This method returns the current Time to Live (TTL) setting on this socket.

Returns:

the current time-to-live

Throws:

IOException - If an error occurs

join

protected abstract void join(InetAddress inetaddr)
                      throws IOException

Causes this socket to join the specified multicast group

Parameters:

inetaddr - The multicast address to join with

Throws:

IOException - If an error occurs

leave

protected abstract void leave(InetAddress inetaddr)
                       throws IOException

Causes the socket to leave the specified multicast group.

Parameters:

inetaddr - The multicast address to leave

Throws:

IOException - If an error occurs

joinGroup

protected abstract void joinGroup(SocketAddress mcastaddr,
             NetworkInterface netIf)
                           throws IOException

Causes this socket to join the specified multicast group on a specified device

Parameters:

mcastaddr - The address to leave

netIf - The specified network interface to join the group at

Throws:

IOException - If an error occurs

Since:

1.4

leaveGroup

protected abstract void leaveGroup(SocketAddress mcastaddr,
              NetworkInterface netIf)
                            throws IOException

Leaves a multicast group

Parameters:

mcastaddr - The address to join

netIf - The specified network interface to leave the group at

Throws:

IOException - If an error occurs

Since:

1.4

getFileDescriptor

protected FileDescriptor getFileDescriptor()

Returns the FileDescriptor for this socket

Returns:

the file descriptor associated with this socket

getLocalPort

protected int getLocalPort()

Returns the local port this socket is bound to

Returns:

the local port