Полезная информация

Java Fundamental Classes Reference

Previous Chapter 15
The java.net Package
Next
 

DatagramSocketImpl

Name

DatagramSocketImpl

Synopsis

Class Name:

java.net.DatagramSocketImpl

Superclass:

java.lang.Object

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

Description

The DatagramSocketImpl class is an abstract class that defines the bulk of the methods that make the DatagramSocket and MulticastSocket classes work. Non-public subclasses of DatagramSocketImpl provide platform-specific implementations of datagram socket communication.

Class Summary

public abstract class java.net.DatagramSocketImpl
                      extends java.lang.Object {
  // Variables
  protected FileDescriptor fd;
  protected int localPort;
  // Protected Instance Methods
  protected abstract void bind(int lport, InetAddress laddr);
  protected abstract void close();
  protected abstract void create();
  protected FileDescriptor getFileDescriptor();
  protected int getLocalPort();
  protected abstract byte getTTL();
  protected abstract void join(InetAddress inetaddr);
  protected abstract void leave(InetAddress inetaddr);
  protected abstract int peek(InetAddress i);
  protected abstract void receive(DatagramPacket p);
  protected abstract void send(DatagramPacket p);
  protected abstract void setTTL(byte ttl);
}

Variables

fd

protected FileDescriptor fd

Description

The file descriptor that represents this socket.

localPort

protected int localPort

Description

The local port number of this socket.

Protected Instance Methods

bind

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

Parameters

lport

A port number.

laddr

A local address.

Throws

SocketException

If any kind of socket error occurs.

Description

This method binds the socket to the given address and port. If the address or the port is unavailable, an exception is thrown.

close

protected void close()

Description

This method closes the socket, releasing any system resources it holds.

create

protected abstract void create() throws SocketException

Throws

SocketException

If a socket error occurs.

Description

This method creates a socket that is not bound to an address and port.

getFileDescriptor

protected FileDescriptor getFileDescriptor()

Returns

The file descriptor for this socket.

Description

This method returns the file descriptor associated with this DatagramSocketImpl.

getLocalPort

protected int getLocalPort()

Returns

The port number for this socket.

Description

This method returns the local port to which this DatagramSocketImpl is bound.

getTTL

protected abstract byte getTTL() throws IOException

Returns

The time-to-live (TTL) value for this socket.

Throws

IOException

If any kind of I/O error occurs.

Description

This method returns the TTL value for this socket. This value is the number of hops that an outgoing packet can traverse before it is discarded.

join

 protected abstract void join(InetAddress inetaddr) throws IOException 

Parameters

inetaddr

The IP address of the group to join.

Throws

IOException

If any kind of I/O error occurs.

Description

This method is used by MulticastSocket to join a multicast group. An exception is thrown if the given address is not a multicast address. While the socket is part of a group, it receives all packets that are sent to the group.

leave

 protected abstract void leave(InetAddress inetaddr) throws IOException 

Parameters

inetaddr

The IP address of the group to leave.

Throws

IOException

If any kind of I/O error occurs.

Description

This method is used by MulticastSocket to leave a multicast group. An exception is thrown if the given address is not a multicast address.

peek

protected abstract int peek(InetAddress i) throws IOException

Parameters

i

A reference to an InetAddress object.

Returns

The port number of the next incoming packet.

Throws

IOException

If any kind of I/O error occurs.

Description

This method places the address of the next incoming packet in the given InetAddress object. The method also returns the port number of the next incoming packet. The method looks at the address of an incoming packet to determine if it should be accepted.

receive

 protected abstract void receive(DatagramPacket p) throws IOException 

Parameters

p

The DatagramPacket that receives incoming data.

Throws

IOException

If any kind of I/O error occurs.

Description

This method receives a datagram packet on this socket. After this method returns, the given DatagramPacket contains the packet's data and length, and the sender's address and port number. If the data that was sent is longer that the given packet's data buffer, the data is truncated.

send

protected abstract void send(DatagramPacket p) throws IOException

Parameters

p

The DatagramPacket to be sent.

Throws

IOException

If any kind of I/O error occurs.

Description

This method sends a packet from this socket. The packet data, packet length, destination address, and destination port number are specified by the given DatagramPacket.

setTTL

protected abstract void setTTL(byte ttl) throws IOException

Parameters

ttl

The new TTL value for this socket.

Throws

IOException

If any kind of I/O error occurs.

Description

This method is used to set the TTL value of the socket. The TTL value is the number of hops that an outgoing packet can traverse before it is discarded.

Inherited Methods

Method

Inherited From

Method

Inherited From

clone()

Object

equals(Object)

Object

finalize()

Object

getClass()

Object

hashCode()

Object

notify()

Object

notifyAll()

Object

toString()

Object

wait()

Object

wait(long)

Object

wait(long, int)

Object

   

See Also

DatagramPacket, DatagramSocket, FileDescriptor, InetAddress, IOException, MulticastSocket


Previous Home Next
DatagramSocket Book Index FileNameMap

Java in a Nutshell Java Language Reference Java AWT Java Fundamental Classes Exploring Java