DatagramSocketImpl (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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Java^TM 2 Platform
Std. Ed. v1.4.1

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java.net
Class DatagramSocketImpl

java.lang.Object
  |
  +--java.net.DatagramSocketImpl

All Implemented Interfaces:: SocketOptions

public abstract class DatagramSocketImpl
extends Object
implements SocketOptions

Abstract datagram and multicast socket implementation base class.

Since:: JDK1.1

Field Summary

protected FileDescriptor fd
          The file descriptor object.

protected int localPort
          The local port number.

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()


Method Summary

protected abstract void bind(int lport, InetAddress laddr)
          Binds a datagram socket to a local port and address.

protected abstract void close()
          Close the socket.

protected void connect(InetAddress address, int port)
          Connects a datagram socket to a remote destination.

protected abstract void create()
          Creates a datagram socket.

protected void disconnect()
          Disconnects a datagram socket from its remote destination.

protected FileDescriptor getFileDescriptor()
          Gets the datagram socket file descriptor.

protected int getLocalPort()
          Gets the local port.

protected abstract int getTimeToLive()
          Retrieve the TTL (time-to-live) option.

protected abstract byte getTTL()
          Deprecated. use getTimeToLive instead.

protected abstract void join(InetAddress inetaddr)
          Join the multicast group.

protected abstract void joinGroup(SocketAddress mcastaddr, NetworkInterface netIf)
          Join the multicast group.

protected abstract void leave(InetAddress inetaddr)
          Leave the multicast group.

protected abstract void leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf)
          Leave the multicast group.

protected abstract int peek(InetAddress i)
          Peek at the packet to see who it is from.

protected abstract int peekData(DatagramPacket p)
          Peek at the packet to see who it is from.

protected abstract void receive(DatagramPacket p)
          Receive the datagram packet.

protected abstract void send(DatagramPacket p)
          Sends a datagram packet.

protected abstract void setTimeToLive(int ttl)
          Set the TTL (time-to-live) option.

protected abstract void setTTL(byte ttl)
          Deprecated. use setTimeToLive 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

localPort

protected int localPort

The local port number.

fd

protected FileDescriptor fd

The file descriptor object.

Constructor Detail

DatagramSocketImpl

public DatagramSocketImpl()

Method Detail

create

protected abstract void create()
                        throws SocketException

Creates a datagram socket.

Throws:: SocketException - if there is an error in the underlying protocol, such as a TCP error.

bind

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

Binds a datagram socket to a local port and address.

Parameters:: lport - the local port; laddr - the local address
Throws:: SocketException - if there is an error in the underlying protocol, such as a TCP error.

send

protected abstract void send(DatagramPacket p)
                      throws IOException

Sends a datagram packet. The packet contains the data and the destination address to send the packet to.

Parameters:: p - the packet to be sent.
Throws:: IOException - if an I/O exception occurs while sending the datagram packet.; 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 a datagram socket to a remote destination. This associates the remote address with the local socket so that datagrams may only be sent to this destination and received from this destination. This may be overridden to call a native system connect.

If the remote destination to which the socket is connected does not exist, or is otherwise unreachable, and if an ICMP destination unreachable packet has been received for that address, then a subsequent call to send or receive may throw a PortUnreachableException. Note, there is no guarantee that the exception will be thrown.

Parameters:: address - the remote InetAddress to connect to; port - the remote port number
Throws:: SocketException - may be thrown if the socket cannot be connected to the remote destination
Since:: 1.4

disconnect

protected void disconnect()

Disconnects a datagram socket from its remote destination.

Since:: 1.4

peek

protected abstract int peek(InetAddress i)
                     throws IOException

Peek at the packet to see who it is from.

Parameters:: i - an InetAddress object
Returns:: the address which the packet came from.
Throws:: IOException - if an I/O exception 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

Peek at the packet to see who it is from. The data is returned, but not consumed, so that a subsequent peekData/receive operation will see the same data.

Parameters:: p - the Packet Received.
Returns:: the address which the packet came from.
Throws:: IOException - if an I/O exception 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

receive

protected abstract void receive(DatagramPacket p)
                         throws IOException

Receive the datagram packet.

Parameters:: p - the Packet Received.
Throws:: IOException - if an I/O exception occurs while receiving the datagram packet.; 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.

setTTL

protected abstract void setTTL(byte ttl)
                        throws IOException

Deprecated. use setTimeToLive instead.

Set the TTL (time-to-live) option.

Parameters:: ttl - a byte specifying the TTL value
Throws:: IOException - if an I/O exception occurs while setting the time-to-live option.
See Also:: getTTL()

getTTL

protected abstract byte getTTL()
                        throws IOException

Deprecated. use getTimeToLive instead.

Retrieve the TTL (time-to-live) option.

Returns:: a byte representing the TTL value
Throws:: IOException - if an I/O exception occurs while retrieving the time-to-live option
See Also:: setTTL(byte)

setTimeToLive

protected abstract void setTimeToLive(int ttl)
                               throws IOException