java.net

Class MulticastSocket

java.lang.Object

java.net.DatagramSocket

java.net.MulticastSocket

public class MulticastSocket
extends DatagramSocket

This class models a multicast UDP socket. A multicast address is a class D internet address (one whose most significant bits are 1110). A multicast group consists of a multicast address and a well known port number. All members of the group listening on that address and port will receive all the broadcasts to the group.

Please note that applets are not allowed to use multicast sockets 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

Constructor Summary

Constructors

Constructor and Description
MulticastSocket() Create a MulticastSocket that this not bound to any address
MulticastSocket(int port) Create a multicast socket bound to the specified port
MulticastSocket(SocketAddress address) Create a multicast socket bound to the specified SocketAddress.

Method Summary

Methods

Modifier and Type	Method and Description
InetAddress	getInterface() Returns the interface being used for multicast packets
boolean	getLoopbackMode() Checks if local loopback mode is enabled
NetworkInterface	getNetworkInterface() Gets the local network interface which is used to send multicast messages
int	getTimeToLive() Returns the current value of the "Time to Live" option.
byte	getTTL() Deprecated. 1.2 Replaced by getTimeToLive()
void	joinGroup(InetAddress mcastaddr) Joins the specified multicast group.
void	joinGroup(SocketAddress mcastaddr, NetworkInterface netIf) Joins the specified mulitcast group on a specified interface.
void	leaveGroup(InetAddress mcastaddr) Leaves the specified multicast group
void	leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf) Leaves the specified mulitcast group on a specified interface.
void	send(DatagramPacket packet, byte ttl) Deprecated.
void	setInterface(InetAddress addr) Sets the interface to use for sending multicast packets.
void	setLoopbackMode(boolean disable) Disable/Enable local loopback of multicast packets.
void	setNetworkInterface(NetworkInterface netIf) Sets the local network interface used to send multicast messages
void	setTimeToLive(int ttl) Sets the "Time to Live" value for a socket.
void	setTTL(byte ttl) Deprecated. 1.2 Replaced by setTimeToLive

Methods inherited from class java.net.DatagramSocket

bind, close, connect, connect, disconnect, getBroadcast, getChannel, getInetAddress, getLocalAddress, getLocalPort, getLocalSocketAddress, getPort, getReceiveBufferSize, getRemoteSocketAddress, getReuseAddress, getSendBufferSize, getSoTimeout, getTrafficClass, isBound, isClosed, isConnected, receive, send, setBroadcast, setDatagramSocketImplFactory, setReceiveBufferSize, setReuseAddress, setSendBufferSize, setSoTimeout, setTrafficClass

Methods inherited from class java.lang.Object

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

Constructor Detail

MulticastSocket

public MulticastSocket()
                throws IOException

Create a MulticastSocket that this not bound to any address

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkListen method doesn't allow the operation

MulticastSocket

public MulticastSocket(int port)
                throws IOException

Create a multicast socket bound to the specified port

Parameters:

port - The port to bind to

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkListen method doesn't allow the operation

MulticastSocket

public MulticastSocket(SocketAddress address)
                throws IOException

Create a multicast socket bound to the specified SocketAddress.

Parameters:

address - The SocketAddress the multicast socket will be bound to

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkListen method doesn't allow the operation

Since:

1.4

Method Detail

getInterface

public InetAddress getInterface()
                         throws SocketException

Returns the interface being used for multicast packets

Returns:

The multicast interface

Throws:

SocketException - If an error occurs

getTTL

public byte getTTL()
            throws IOException

Deprecated. 1.2 Replaced by getTimeToLive()

Returns the current value of the "Time to Live" option. This is the number of hops a packet can make before it "expires". This method id deprecated. Use getTimeToLive instead.

Returns:

The TTL value

Throws:

IOException - If an error occurs

See Also:

getTimeToLive()

getTimeToLive

public int getTimeToLive()
                  throws IOException

Returns the current value of the "Time to Live" option. This is the number of hops a packet can make before it "expires".

Returns:

The TTL value

Throws:

IOException - If an error occurs

Since:

1.2

setInterface

public void setInterface(InetAddress addr)
                  throws SocketException

Sets the interface to use for sending multicast packets.

Parameters:

addr - The new interface to use.

Throws:

SocketException - If an error occurs.

Since:

1.4

setNetworkInterface

public void setNetworkInterface(NetworkInterface netIf)
                         throws SocketException

Sets the local network interface used to send multicast messages

Parameters:

netIf - The local network interface used to send multicast messages

Throws:

SocketException - If an error occurs

Since:

1.4

See Also:

getNetworkInterface()

getNetworkInterface

public NetworkInterface getNetworkInterface()
                                     throws SocketException

Gets the local network interface which is used to send multicast messages

Returns:

The local network interface to send multicast messages

Throws:

SocketException - If an error occurs

Since:

1.4

See Also:

setNetworkInterface(NetworkInterface netIf)

setLoopbackMode

public void setLoopbackMode(boolean disable)
                     throws SocketException

Disable/Enable local loopback of multicast packets. The option is used by the platform's networking code as a hint for setting whether multicast data will be looped back to the local socket. Because this option is a hint, applications that want to verify what loopback mode is set to should call #getLoopbackMode

Parameters:

disable - True to disable loopback mode

Throws:

SocketException - If an error occurs

Since:

1.4

getLoopbackMode

public boolean getLoopbackMode()
                        throws SocketException

Checks if local loopback mode is enabled

Returns:

true if loopback mode is enabled, false otherwise

Throws:

SocketException - If an error occurs

Since:

1.4

setTTL

public void setTTL(byte ttl)
            throws IOException

Deprecated. 1.2 Replaced by setTimeToLive

Sets the "Time to Live" value for a socket. The value must be between 1 and 255.

Parameters:

ttl - The new TTL value

Throws:

IOException - If an error occurs

See Also:

setTimeToLive(int ttl)

setTimeToLive

public void setTimeToLive(int ttl)
                   throws IOException

Sets the "Time to Live" value for a socket. The value must be between 0 and 255, inclusive.

Parameters:

ttl - The new TTL value

Throws:

IOException - If an error occurs

Since:

1.2

joinGroup

public void joinGroup(InetAddress mcastaddr)
               throws IOException

Joins the specified multicast group.

Parameters:

mcastaddr - The address of the group to join

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkMulticast method doesn't allow the operation

leaveGroup

public void leaveGroup(InetAddress mcastaddr)
                throws IOException

Leaves the specified multicast group

Parameters:

mcastaddr - The address of the group to leave

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkMulticast method doesn't allow the operation

joinGroup

public void joinGroup(SocketAddress mcastaddr,
             NetworkInterface netIf)
               throws IOException

Joins the specified mulitcast group on a specified interface.

Parameters:

mcastaddr - The multicast address to join

netIf - The local network interface to receive the multicast messages on or null to defer the interface set by #setInterface or #setNetworkInterface

Throws:

IOException - If an error occurs

IllegalArgumentException - If address type is not supported

SecurityException - If a security manager exists and its checkMulticast method doesn't allow the operation

Since:

1.4

See Also:

setInterface(InetAddress addr), setNetworkInterface(NetworkInterface netIf)

leaveGroup

public void leaveGroup(SocketAddress mcastaddr,
              NetworkInterface netIf)
                throws IOException

Leaves the specified mulitcast group on a specified interface.

Parameters:

mcastaddr - The multicast address to leave

netIf - The local networki interface or null to defer to the interface set by setInterface or setNetworkInterface

Throws:

IOException - If an error occurs

IllegalArgumentException - If address type is not supported

SecurityException - If a security manager exists and its checkMulticast method doesn't allow the operation

Since:

1.4

See Also:

setInterface(InetAddress addr), setNetworkInterface(NetworkInterface netIf)

send

public void send(DatagramPacket packet,
        byte ttl)
          throws IOException

Deprecated.

Sends a packet of data to a multicast address with a TTL that is different from the default TTL on this socket. The default TTL for the socket is not changed.

Parameters:

packet - The packet of data to send

ttl - The TTL for this packet

Throws:

IOException - If an error occurs

SecurityException - If a security manager exists and its checkConnect or checkMulticast method doesn't allow the operation