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| java.lang.Object
 java.net.DatagramSocket
All known Subclasses: java.net.MulticastSocket,
| DatagramSocket | | public class DatagramSocket implements java.io.Closeable(Code) | | This class represents a socket for sending and receiving datagram packets.
A datagram socket is the sending or receiving point for a packet
delivery service. Each packet sent or received on a datagram socket
is individually addressed and routed. Multiple packets sent from
one machine to another may be routed differently, and may arrive in
any order.
UDP broadcasts sends are always enabled on a DatagramSocket.
In order to receive broadcast packets a DatagramSocket
should be bound to the wildcard address. In some
implementations, broadcast packets may also be received when
a DatagramSocket is bound to a more specific address.
Example:
DatagramSocket s = new DatagramSocket(null);
s.bind(new InetSocketAddress(8888));
Which is equivalent to:
DatagramSocket s = new DatagramSocket(8888);
Both cases will create a DatagramSocket able to receive broadcasts on
UDP port 8888.
author:
Pavani Diwanji
version:
1.111, 06/11/07
See Also: java.net.DatagramPacket
See Also: java.nio.channels.DatagramChannel
since:
JDK1.0 |
| Constructor Summary | |
| public | DatagramSocket()
Constructs a datagram socket and binds it to any available port
on the local host machine. | | protected | DatagramSocket(DatagramSocketImpl impl)
Creates an unbound datagram socket with the specified
DatagramSocketImpl. | | public | DatagramSocket(SocketAddress bindaddr)
Creates a datagram socket, bound to the specified local
socket address.
If, if the address is null, creates an unbound socket.
If there is a security manager,
its checkListen method is first called
with the port from the socket address
as its argument to ensure the operation is allowed. | | public | DatagramSocket(int port)
Constructs a datagram socket and binds it to the specified port
on the local host machine. | | public | DatagramSocket(int port, InetAddress laddr)
Creates a datagram socket, bound to the specified local
address. |
| Method Summary | |
| public synchronized void | bind(SocketAddress addr)
Binds this DatagramSocket to a specific address & port. | | public void | close()
Closes this datagram socket. | | public void | connect(InetAddress address, int port)
Connects the socket to a remote address for this socket. | | public void | connect(SocketAddress addr)
Connects this socket to a remote socket address (IP address + port number). | | void | createImpl()
| | public void | disconnect()
Disconnects the socket. | | public synchronized boolean | getBroadcast()
Tests if SO_BROADCAST is enabled. | | public DatagramChannel | getChannel()
Returns the unique
java.nio.channels.DatagramChannel object
associated with this datagram socket, if any. | | DatagramSocketImpl | getImpl()
Get the DatagramSocketImpl attached to this socket,
creating it if necessary. | | public InetAddress | getInetAddress()
Returns the address to which this socket is connected. | | public InetAddress | getLocalAddress()
Gets the local address to which the socket is bound. | | public int | getLocalPort()
Returns the port number on the local host to which this socket
is bound. | | public SocketAddress | getLocalSocketAddress()
Returns the address of the endpoint this socket is bound to. | | public int | getPort()
Returns the port number to which this socket is connected. | | public synchronized int | getReceiveBufferSize()
Get value of the SO_RCVBUF option for this DatagramSocket, that is the
buffer size used by the platform for input on this DatagramSocket. | | public SocketAddress | getRemoteSocketAddress()
Returns the address of the endpoint this socket is connected to, or
null if it is unconnected. | | public synchronized boolean | getReuseAddress()
Tests if SO_REUSEADDR is enabled.
a boolean indicating whether or not SO_REUSEADDR is enabled.
exception:
SocketException - if there is an errorin the underlying protocol, such as an UDP error. | | public synchronized int | getSendBufferSize()
Get value of the SO_SNDBUF option for this DatagramSocket, that is the
buffer size used by the platform for output on this DatagramSocket. | | public synchronized int | getSoTimeout()
Retrieve setting for SO_TIMEOUT. | | public synchronized int | getTrafficClass()
Gets traffic class or type-of-service in the IP datagram
header for packets sent from this DatagramSocket. | | public boolean | isBound()
Returns the binding state of the socket. | | public boolean | isClosed()
Returns whether the socket is closed or not. | | public boolean | isConnected()
Returns the connection state of the socket. | | public synchronized void | receive(DatagramPacket p)
Receives a datagram packet from this socket. | | public void | send(DatagramPacket p)
Sends a datagram packet from this socket. | | public synchronized void | setBroadcast(boolean on)
Enable/disable SO_BROADCAST. | | public static synchronized void | setDatagramSocketImplFactory(DatagramSocketImplFactory fac)
Sets the datagram socket implementation factory for the
application. | | public synchronized void | setReceiveBufferSize(int size)
Sets the SO_RCVBUF option to the specified value for this
DatagramSocket. | | public synchronized void | setReuseAddress(boolean on)
Enable/disable the SO_REUSEADDR socket option.
For UDP sockets it may be necessary to bind more than one
socket to the same socket address. | | public synchronized void | setSendBufferSize(int size)
Sets the SO_SNDBUF option to the specified value for this
DatagramSocket. | | public synchronized void | setSoTimeout(int timeout)
Enable/disable SO_TIMEOUT with the specified timeout, in
milliseconds. | | public synchronized void | setTrafficClass(int tc)
Sets traffic class or type-of-service octet in the IP
datagram header for datagrams sent from this DatagramSocket. |
| ST_CONNECTED | | final static int ST_CONNECTED(Code) | | |
| ST_CONNECTED_NO_IMPL | | final static int ST_CONNECTED_NO_IMPL(Code) | | |
| ST_NOT_CONNECTED | | final static int ST_NOT_CONNECTED(Code) | | |
| connectState | | int connectState(Code) | | |
| connectedPort | | int connectedPort(Code) | | |
| oldImpl | | boolean oldImpl(Code) | | Are we using an older DatagramSocketImpl?
|
| DatagramSocket | | public DatagramSocket() throws SocketException(Code) | | Constructs a datagram socket and binds it to any available port
on the local host machine. The socket will be bound to the
InetAddress.isAnyLocalAddress wildcard address,
an IP address chosen by the kernel.
If there is a security manager,
its checkListen method is first called
with 0 as its argument to ensure the operation is allowed.
This could result in a SecurityException.
exception:
SocketException - if the socket could not be opened,or the socket could not bind to the specified local port.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
See Also: SecurityManager.checkListen |
| DatagramSocket | | protected DatagramSocket(DatagramSocketImpl impl)(Code) | | Creates an unbound datagram socket with the specified
DatagramSocketImpl.
Parameters:
impl - an instance of a DatagramSocketImplthe subclass wishes to use on the DatagramSocket.
since:
1.4 |
| DatagramSocket | | public DatagramSocket(SocketAddress bindaddr) throws SocketException(Code) | | Creates a datagram socket, bound to the specified local
socket address.
If, if the address is null, creates an unbound socket.
If there is a security manager,
its checkListen method is first called
with the port from the socket address
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
Parameters:
bindaddr - local socket address to bind, or nullfor an unbound socket.
exception:
SocketException - if the socket could not be opened,or the socket could not bind to the specified local port.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
See Also: SecurityManager.checkListen
since:
1.4 |
| DatagramSocket | | public DatagramSocket(int port) throws SocketException(Code) | | Constructs a datagram socket and binds it to the specified port
on the local host machine. The socket will be bound to the
InetAddress.isAnyLocalAddress wildcard address,
an IP address chosen by the kernel.
If there is a security manager,
its checkListen method is first called
with the port argument
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
Parameters:
port - port to use.
exception:
SocketException - if the socket could not be opened,or the socket could not bind to the specified local port.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
See Also: SecurityManager.checkListen |
| DatagramSocket | | public DatagramSocket(int port, InetAddress laddr) throws SocketException(Code) | | Creates a datagram socket, bound to the specified local
address. The local port must be between 0 and 65535 inclusive.
If the IP address is 0.0.0.0, the socket will be bound to the
InetAddress.isAnyLocalAddress wildcard address,
an IP address chosen by the kernel.
If there is a security manager,
its checkListen method is first called
with the port argument
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
Parameters:
port - local port to use
Parameters:
laddr - local address to bind
exception:
SocketException - if the socket could not be opened,or the socket could not bind to the specified local port.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
See Also: SecurityManager.checkListen
since:
JDK1.1 |
| bind | | public synchronized void bind(SocketAddress addr) throws SocketException(Code) | | Binds this DatagramSocket to a specific address & port.
If the address is null, then the system will pick up
an ephemeral port and a valid local address to bind the socket.
Parameters:
addr - The address & port to bind to.
throws:
SocketException - if any error happens during the bind, or if thesocket is already bound.
throws:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
throws:
IllegalArgumentException - if addr is a SocketAddress subclassnot supported by this socket.
since:
1.4 |
| close | | public void close()(Code) | | Closes this datagram socket.
Any thread currently blocked in
DatagramSocket.receive upon this socket
will throw a
SocketException .
If this socket has an associated channel then the channel is closed
as well.
|
| connect | | public void connect(InetAddress address, int port)(Code) | | Connects the socket to a remote address for this socket. When a
socket is connected to a remote address, packets may only be
sent to or received from that address. By default a datagram
socket is not connected.
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.
A caller's permission to send and receive datagrams to a
given host and port are checked at connect time. When a socket
is connected, receive and send will not
perform any security checks on incoming and outgoing
packets, other than matching the packet's and the socket's
address and port. On a send operation, if the packet's address
is set and the packet's address and the socket's address do not
match, an IllegalArgumentException will be thrown. A socket
connected to a multicast address may only be used to send packets.
Parameters:
address - the remote address for the socket
Parameters:
port - the remote port for the socket.
exception:
IllegalArgumentException - if the address is null,or the port is out of range.
exception:
SecurityException - if the caller is not allowed tosend datagrams to and receive datagrams from the address and port.
See Also: DatagramSocket.disconnect
See Also: DatagramSocket.send
See Also: DatagramSocket.receive
See Also: |
| disconnect | | public void disconnect()(Code) | | Disconnects the socket. If the socket is closed or not connected,
then this method has no effect.
See Also: DatagramSocket.connect |
| getInetAddress | | public InetAddress getInetAddress()(Code) | | Returns the address to which this socket is connected. Returns
null if the socket is not connected.
If the socket was connected prior to being
DatagramSocket.close closed ,
then this method will continue to return the connected address
after the socket is closed.
the address to which this socket is connected. |
| getLocalAddress | | public InetAddress getLocalAddress()(Code) | | Gets the local address to which the socket is bound.
If there is a security manager, its
checkConnect method is first called
with the host address and -1
as its arguments to see if the operation is allowed.
See Also: SecurityManager.checkConnect the local address to which the socket is bound, null if the socket is closed, oran InetAddress representing InetAddress.isAnyLocalAddress wildcardaddress if either the socket is not bound, orthe security manager checkConnectmethod does not allow the operation
since:
1.1 |
| getLocalPort | | public int getLocalPort()(Code) | | Returns the port number on the local host to which this socket
is bound.
the port number on the local host to which this socket is bound,-1 if the socket is closed, or0 if it is not bound yet. |
| getPort | | public int getPort()(Code) | | Returns the port number to which this socket is connected.
Returns -1 if the socket is not connected.
If the socket was connected prior to being
DatagramSocket.close closed ,
then this method will continue to return the connected port number
after the socket is closed.
the port number to which this socket is connected. |
| getReceiveBufferSize | | public synchronized int getReceiveBufferSize() throws SocketException(Code) | | Get value of the SO_RCVBUF option for this DatagramSocket, that is the
buffer size used by the platform for input on this DatagramSocket.
the value of the SO_RCVBUF option for this DatagramSocket
exception:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
See Also: DatagramSocket.setReceiveBufferSize(int) |
| getSendBufferSize | | public synchronized int getSendBufferSize() throws SocketException(Code) | | Get value of the SO_SNDBUF option for this DatagramSocket, that is the
buffer size used by the platform for output on this DatagramSocket.
the value of the SO_SNDBUF option for this DatagramSocket
exception:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
See Also: DatagramSocket.setSendBufferSize |
| getSoTimeout | | public synchronized int getSoTimeout() throws SocketException(Code) | | Retrieve setting for SO_TIMEOUT. 0 returns implies that the
option is disabled (i.e., timeout of infinity).
the setting for SO_TIMEOUT
throws:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
since:
JDK1.1
See Also: DatagramSocket.setSoTimeout(int) |
| isBound | | public boolean isBound()(Code) | | Returns the binding state of the socket.
If the socket was bound prior to being
DatagramSocket.close closed ,
then this method will continue to return true
after the socket is closed.
true if the socket successfully bound to an address
since:
1.4 |
| isClosed | | public boolean isClosed()(Code) | | Returns whether the socket is closed or not.
true if the socket has been closed
since:
1.4 |
| isConnected | | public boolean isConnected()(Code) | | Returns the connection state of the socket.
If the socket was connected prior to being
DatagramSocket.close closed ,
then this method will continue to return true
after the socket is closed.
true if the socket successfully connected to a server
since:
1.4 |
| receive | | public synchronized void receive(DatagramPacket p) throws IOException(Code) | | Receives a datagram packet from this socket. When this method
returns, the DatagramPacket's buffer is filled with
the data received. The datagram packet also contains the sender's
IP address, and the port number on the sender's machine.
This method blocks until a datagram is received. The
length field of the datagram packet object contains
the length of the received message. If the message is longer than
the packet's length, the message is truncated.
If there is a security manager, a packet cannot be received if the
security manager's checkAccept method
does not allow it.
Parameters:
p - the DatagramPacket into which to placethe incoming data.
exception:
IOException - if an I/O error occurs.
exception:
SocketTimeoutException - if setSoTimeout was previously calledand the timeout has expired.
exception:
PortUnreachableException - may be thrown if the socket is connectedto a currently unreachable destination. Note, there is no guarantee that theexception will be thrown.
exception:
java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel,and the channel is in non-blocking mode.
See Also: java.net.DatagramPacket
See Also: java.net.DatagramSocket |
| send | | public void send(DatagramPacket p) throws IOException(Code) | | Sends a datagram packet from this socket. The
DatagramPacket includes information indicating the
data to be sent, its length, the IP address of the remote host,
and the port number on the remote host.
If there is a security manager, and the socket is not currently
connected to a remote address, this method first performs some
security checks. First, if p.getAddress().isMulticastAddress()
is true, this method calls the
security manager's checkMulticast method
with p.getAddress() as its argument.
If the evaluation of that expression is false,
this method instead calls the security manager's
checkConnect method with arguments
p.getAddress().getHostAddress() and
p.getPort(). Each call to a security manager method
could result in a SecurityException if the operation is not allowed.
Parameters:
p - the DatagramPacket to be sent.
exception:
IOException - if an I/O error occurs.
exception:
SecurityException - if a security manager exists and its checkMulticast or checkConnect method doesn't allow the send.
exception:
PortUnreachableException - may be thrown if the socket is connectedto a currently unreachable destination. Note, there is no guarantee that the exception will be thrown.
exception:
java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel,and the channel is in non-blocking mode.
exception:
IllegalArgumentException - if the socket is connected,and connected address and packet address differ.
See Also: java.net.DatagramPacket
See Also: SecurityManager.checkMulticast(InetAddress)
See Also: SecurityManager.checkConnect |
| setBroadcast | | public synchronized void setBroadcast(boolean on) throws SocketException(Code) | | Enable/disable SO_BROADCAST.
Parameters:
on - whether or not to have broadcast turned on.
exception:
SocketException - if there is an errorin the underlying protocol, such as an UDP error.
since:
1.4
See Also: DatagramSocket.getBroadcast() |
| setDatagramSocketImplFactory | | public static synchronized void setDatagramSocketImplFactory(DatagramSocketImplFactory fac) throws IOException(Code) | | Sets the datagram socket implementation factory for the
application. The factory can be specified only once.
When an application creates a new datagram socket, the socket
implementation factory's createDatagramSocketImpl method is
called to create the actual datagram socket implementation.
Passing null to the method is a no-op unless the factory
was already set.
If there is a security manager, this method first calls
the security manager's checkSetFactory method
to ensure the operation is allowed.
This could result in a SecurityException.
Parameters:
fac - the desired factory.
exception:
IOException - if an I/O error occurs when setting thedatagram socket factory.
exception:
SocketException - if the factory is already defined.
exception:
SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also: java.net.DatagramSocketImplFactory.createDatagramSocketImpl
See Also: SecurityManager.checkSetFactory
since:
1.3 |
| setReceiveBufferSize | | public synchronized void setReceiveBufferSize(int size) throws SocketException(Code) | | Sets the SO_RCVBUF option to the specified value for this
DatagramSocket. The SO_RCVBUF option is used by the
the network implementation as a hint to size the underlying
network I/O buffers. The SO_RCVBUF setting may also be used
by the network implementation to determine the maximum size
of the packet that can be received on this socket.
Because SO_RCVBUF is a hint, applications that want to
verify what size the buffers were set to should call
DatagramSocket.getReceiveBufferSize() .
Increasing SO_RCVBUF may allow the network implementation
to buffer multiple packets when packets arrive faster than
are being received using
DatagramSocket.receive(DatagramPacket) .
Note: It is implementation specific if a packet larger
than SO_RCVBUF can be received.
Parameters:
size - the size to which to set the receive buffersize. This value must be greater than 0.
exception:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
exception:
IllegalArgumentException - if the value is 0 or isnegative.
See Also: DatagramSocket.getReceiveBufferSize() |
| setReuseAddress | | public synchronized void setReuseAddress(boolean on) throws SocketException(Code) | | Enable/disable the SO_REUSEADDR socket option.
For UDP sockets it may be necessary to bind more than one
socket to the same socket address. This is typically for the
purpose of receiving multicast packets
(See
java.net.MulticastSocket ). The
SO_REUSEADDR socket option allows multiple
sockets to be bound to the same socket address if the
SO_REUSEADDR socket option is enabled prior
to binding the socket using
DatagramSocket.bind(SocketAddress) .
Note: This functionality is not supported by all existing platforms,
so it is implementation specific whether this option will be ignored
or not. However, if it is not supported then
DatagramSocket.getReuseAddress() will always return false.
When a DatagramSocket is created the initial setting
of SO_REUSEADDR is disabled.
The behaviour when SO_REUSEADDR is enabled or
disabled after a socket is bound (See
DatagramSocket.isBound() )
is not defined.
Parameters:
on - whether to enable or disable the
exception:
SocketException - if an error occurs enabling ordisabling the SO_RESUEADDR socket option,or the socket is closed.
since:
1.4
See Also: DatagramSocket.getReuseAddress()
See Also:
See Also: DatagramSocket.bind(SocketAddress)
See Also:
See Also: DatagramSocket.isBound()
See Also: DatagramSocket.isClosed() |
| setSendBufferSize | | public synchronized void setSendBufferSize(int size) throws SocketException(Code) | | Sets the SO_SNDBUF option to the specified value for this
DatagramSocket. The SO_SNDBUF option is used by the
network implementation as a hint to size the underlying
network I/O buffers. The SO_SNDBUF setting may also be used
by the network implementation to determine the maximum size
of the packet that can be sent on this socket.
As SO_SNDBUF is a hint, applications that want to verify
what size the buffer is should call
DatagramSocket.getSendBufferSize() .
Increasing the buffer size may allow multiple outgoing packets
to be queued by the network implementation when the send rate
is high.
Note: If
DatagramSocket.send(DatagramPacket) is used to send a
DatagramPacket that is larger than the setting
of SO_SNDBUF then it is implementation specific if the
packet is sent or discarded.
Parameters:
size - the size to which to set the send buffersize. This value must be greater than 0.
exception:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
exception:
IllegalArgumentException - if the value is 0 or isnegative.
See Also: DatagramSocket.getSendBufferSize() |
| setSoTimeout | | public synchronized void setSoTimeout(int timeout) throws SocketException(Code) | | Enable/disable SO_TIMEOUT with the specified timeout, in
milliseconds. With this option set to a non-zero timeout,
a call to receive() for this DatagramSocket
will block for only this amount of time. If the timeout expires,
a java.net.SocketTimeoutException is raised, though the
DatagramSocket is still valid. The option must be enabled
prior to entering the blocking operation to have effect. The
timeout must be > 0.
A timeout of zero is interpreted as an infinite timeout.
Parameters:
timeout - the specified timeout in milliseconds.
throws:
SocketException - if there is an error in the underlying protocol, such as an UDP error.
since:
JDK1.1
See Also: DatagramSocket.getSoTimeout() |
| setTrafficClass | | public synchronized void setTrafficClass(int tc) throws SocketException(Code) | | Sets traffic class or type-of-service octet in the IP
datagram header for datagrams sent from this DatagramSocket.
As the underlying network implementation may ignore this
value applications should consider it a hint.
The tc must be in the range 0 <= tc <=
255 or an IllegalArgumentException will be thrown.
Notes:
For Internet Protocol v4 the value consists of an
integer, the least significant 8 bits of which
represent the value of the TOS octet in IP packets sent by
the socket.
RFC 1349 defines the TOS values as follows:
IPTOS_LOWCOST (0x02)IPTOS_RELIABILITY (0x04)IPTOS_THROUGHPUT (0x08)IPTOS_LOWDELAY (0x10)
The last low order bit is always ignored as this
corresponds to the MBZ (must be zero) bit.
Setting bits in the precedence field may result in a
SocketException indicating that the operation is not
permitted.
for Internet Protocol v6 tc is the value that
would be placed into the sin6_flowinfo field of the IP header.
Parameters:
tc - an int value for the bitset.
throws:
SocketException - if there is an error setting thetraffic class or type-of-service
since:
1.4
See Also: DatagramSocket.getTrafficClass |
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