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| java.lang.Object
 java.net.ServerSocket
All known Subclasses: javax.net.ssl.SSLServerSocket,
| ServerSocket | | public class ServerSocket implements java.io.Closeable(Code) | | This class implements server sockets. A server socket waits for
requests to come in over the network. It performs some operation
based on that request, and then possibly returns a result to the requester.
The actual work of the server socket is performed by an instance
of the SocketImpl class. An application can
change the socket factory that creates the socket
implementation to configure itself to create sockets
appropriate to the local firewall.
author:
unascribed
version:
1.101, 05/05/07
See Also: java.net.SocketImpl
See Also: java.net.ServerSocket.setSocketFactory(java.net.SocketImplFactory)
See Also: java.nio.channels.ServerSocketChannel
since:
JDK1.0 |
| Constructor Summary | |
| public | ServerSocket()
Creates an unbound server socket. | | public | ServerSocket(int port)
Creates a server socket, bound to the specified port. | | public | ServerSocket(int port, int backlog)
Creates a server socket and binds it to the specified local port
number, with the specified backlog. | | public | ServerSocket(int port, int backlog, InetAddress bindAddr)
Create a server with the specified port, listen backlog, and
local IP address to bind to. |
| Method Summary | |
| public Socket | accept()
Listens for a connection to be made to this socket and accepts
it. | | public void | bind(SocketAddress endpoint)
Binds the ServerSocket to a specific address
(IP address and port number). | | public void | bind(SocketAddress endpoint, int backlog)
Binds the ServerSocket to a specific address
(IP address and port number).
If the address is null, then the system will pick up
an ephemeral port and a valid local address to bind the socket.
The backlog argument must be a positive
value greater than 0. | | public void | close()
Closes this socket. | | void | createImpl()
Creates the socket implementation. | | public ServerSocketChannel | getChannel()
Returns the unique
java.nio.channels.ServerSocketChannel object
associated with this socket, if any. | | SocketImpl | getImpl()
Get the SocketImpl attached to this socket, creating
it if necessary. | | public InetAddress | getInetAddress()
Returns the local address of this server socket. | | public int | getLocalPort()
Returns the port number on which this socket is listening. | | public SocketAddress | getLocalSocketAddress()
Returns the address of the endpoint this socket is bound to, or
null if it is not bound yet. | | public synchronized int | getReceiveBufferSize()
Gets the value of the SO_RCVBUF option for this ServerSocket,
that is the proposed buffer size that will be used for Sockets accepted
from this ServerSocket.
Note, the value actually set in the accepted socket is determined by
calling
Socket.getReceiveBufferSize .
the value of the SO_RCVBUF option for this Socket.
exception:
SocketException - if there is an errorin the underlying protocol, such as a TCP error. | | public 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 a TCP error. | | public synchronized int | getSoTimeout()
Retrieve setting for SO_TIMEOUT. | | final protected void | implAccept(Socket s)
Subclasses of ServerSocket use this method to override accept()
to return their own subclass of socket. | | public boolean | isBound()
Returns the binding state of the ServerSocket. | | public boolean | isClosed()
Returns the closed state of the ServerSocket. | | void | setBound()
| | void | setCreated()
| | public void | setPerformancePreferences(int connectionTime, int latency, int bandwidth)
Sets performance preferences for this ServerSocket.
Sockets use the TCP/IP protocol by default. | | public synchronized void | setReceiveBufferSize(int size)
Sets a default proposed value for the SO_RCVBUF option for sockets
accepted from this ServerSocket. | | public void | setReuseAddress(boolean on)
Enable/disable the SO_REUSEADDR socket option.
When a TCP connection is closed the connection may remain
in a timeout state for a period of time after the connection
is closed (typically known as the TIME_WAIT state
or 2MSL wait state).
For applications using a well known socket address or port
it may not be possible to bind a socket to the required
SocketAddress if there is a connection in the
timeout state involving the socket address or port. | | public synchronized void | setSoTimeout(int timeout)
Enable/disable SO_TIMEOUT with the specified timeout, in
milliseconds. | | public static synchronized void | setSocketFactory(SocketImplFactory fac)
Sets the server socket implementation factory for the
application. | | public String | toString()
Returns the implementation address and implementation port of
this socket as a String. |
| ServerSocket | | public ServerSocket() throws IOException(Code) | | Creates an unbound server socket.
exception:
IOException - IO error when opening the socket. |
| ServerSocket | | public ServerSocket(int port) throws IOException(Code) | | Creates a server socket, bound to the specified port. A port number
of 0 means that the port number is automatically
allocated, typically from an ephemeral port range. This port
number can then be retrieved by calling
ServerSocket.getLocalPort getLocalPort .
The maximum queue length for incoming connection indications (a
request to connect) is set to 50. If a connection
indication arrives when the queue is full, the connection is refused.
If the application has specified a server socket factory, that
factory's createSocketImpl method is called to create
the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager,
its checkListen method is called
with the port argument
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
Parameters:
port - the port number, or 0 to use a portnumber that is automatically allocated.
exception:
IOException - if an I/O error occurs when opening the socket.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
exception:
IllegalArgumentException - if the port parameter is outsidethe specified range of valid port values, which is between0 and 65535, inclusive.
See Also: java.net.SocketImpl
See Also: java.net.SocketImplFactory.createSocketImpl
See Also: java.net.ServerSocket.setSocketFactory(java.net.SocketImplFactory)
See Also: SecurityManager.checkListen |
| ServerSocket | | public ServerSocket(int port, int backlog) throws IOException(Code) | | Creates a server socket and binds it to the specified local port
number, with the specified backlog.
A port number of 0 means that the port number is
automatically allocated, typically from an ephemeral port range.
This port number can then be retrieved by calling
ServerSocket.getLocalPort getLocalPort .
The maximum queue length for incoming connection indications (a
request to connect) is set to the backlog parameter. If
a connection indication arrives when the queue is full, the
connection is refused.
If the application has specified a server socket factory, that
factory's createSocketImpl method is called to create
the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager,
its checkListen method is called
with the port argument
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
The backlog argument must be a positive
value greater than 0. If the value passed is equal or less
than 0, then the default value will be assumed.
Parameters:
port - the port number, or 0 to use a portnumber that is automatically allocated.
Parameters:
backlog - the maximum length of the queue.
exception:
IOException - if an I/O error occurs when opening the socket.
exception:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
exception:
IllegalArgumentException - if the port parameter is outsidethe specified range of valid port values, which is between0 and 65535, inclusive.
See Also: java.net.SocketImpl
See Also: java.net.SocketImplFactory.createSocketImpl
See Also: java.net.ServerSocket.setSocketFactory(java.net.SocketImplFactory)
See Also: SecurityManager.checkListen |
| ServerSocket | | public ServerSocket(int port, int backlog, InetAddress bindAddr) throws IOException(Code) | | Create a server with the specified port, listen backlog, and
local IP address to bind to. The bindAddr argument
can be used on a multi-homed host for a ServerSocket that
will only accept connect requests to one of its addresses.
If bindAddr is null, it will default accepting
connections on any/all local addresses.
The port must be between 0 and 65535, inclusive.
A port number of 0 means that the port number is
automatically allocated, typically from an ephemeral port range.
This port number can then be retrieved by calling
ServerSocket.getLocalPort getLocalPort .
If there is a security manager, this method
calls its checkListen method
with the port argument
as its argument to ensure the operation is allowed.
This could result in a SecurityException.
The backlog argument must be a positive
value greater than 0. If the value passed is equal or less
than 0, then the default value will be assumed.
Parameters:
port - the port number, or 0 to use a portnumber that is automatically allocated.
Parameters:
backlog - the listen backlog
Parameters:
bindAddr - the local InetAddress the server will bind to
throws:
SecurityException - if a security manager exists and its checkListen method doesn't allow the operation.
throws:
IOException - if an I/O error occurs when opening the socket.
exception:
IllegalArgumentException - if the port parameter is outsidethe specified range of valid port values, which is between0 and 65535, inclusive.
See Also: SocketOptions
See Also: SocketImpl
See Also: SecurityManager.checkListen
since:
JDK1.1 |
| accept | | public Socket accept() throws IOException(Code) | | Listens for a connection to be made to this socket and accepts
it. The method blocks until a connection is made.
A new Socket s is created and, if there
is a security manager,
the security manager's checkAccept method is called
with s.getInetAddress().getHostAddress() and
s.getPort()
as its arguments to ensure the operation is allowed.
This could result in a SecurityException.
exception:
IOException - if an I/O error occurs when waiting for aconnection.
exception:
SecurityException - if a security manager exists and its checkAccept method doesn't allow the operation.
exception:
SocketTimeoutException - if a timeout was previously set with setSoTimeout andthe timeout has been reached.
exception:
java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel, the channel is innon-blocking mode, and there is no connection ready to beaccepted the new Socket
See Also: SecurityManager.checkAccept |
| bind | | public void bind(SocketAddress endpoint) throws IOException(Code) | | Binds the ServerSocket to a specific address
(IP address and port number).
If the address is null, then the system will pick up
an ephemeral port and a valid local address to bind the socket.
Parameters:
endpoint - The IP address & port number to bind to.
throws:
IOException - if the bind operation fails, or if the socketis already bound.
throws:
SecurityException - if a SecurityManager is present andits checkListen method doesn't allow the operation.
throws:
IllegalArgumentException - if endpoint is aSocketAddress subclass not supported by this socket
since:
1.4 |
| bind | | public void bind(SocketAddress endpoint, int backlog) throws IOException(Code) | | Binds the ServerSocket to a specific address
(IP address and port number).
If the address is null, then the system will pick up
an ephemeral port and a valid local address to bind the socket.
The backlog argument must be a positive
value greater than 0. If the value passed is equal or less
than 0, then the default value will be assumed.
Parameters:
endpoint - The IP address & port number to bind to.
Parameters:
backlog - The listen backlog length.
throws:
IOException - if the bind operation fails, or if the socketis already bound.
throws:
SecurityException - if a SecurityManager is present andits checkListen method doesn't allow the operation.
throws:
IllegalArgumentException - if endpoint is aSocketAddress subclass not supported by this socket
since:
1.4 |
| getInetAddress | | public InetAddress getInetAddress()(Code) | | Returns the local address of this server socket.
If the socket was bound prior to being
ServerSocket.close closed ,
then this method will continue to return the local address
after the socket is closed.
the address to which this socket is bound,or null if the socket is unbound. |
| getLocalPort | | public int getLocalPort()(Code) | | Returns the port number on which this socket is listening.
If the socket was bound prior to being
ServerSocket.close closed ,
then this method will continue to return the port number
after the socket is closed.
the port number to which this socket is listening or-1 if the socket is not bound yet. |
| getReceiveBufferSize | | public synchronized int getReceiveBufferSize() throws SocketException(Code) | | Gets the value of the SO_RCVBUF option for this ServerSocket,
that is the proposed buffer size that will be used for Sockets accepted
from this ServerSocket.
Note, the value actually set in the accepted socket is determined by
calling
Socket.getReceiveBufferSize .
the value of the SO_RCVBUF option for this Socket.
exception:
SocketException - if there is an errorin the underlying protocol, such as a TCP error.
See Also: ServerSocket.setReceiveBufferSize(int)
since:
1.4 |
| getSoTimeout | | public synchronized int getSoTimeout() throws IOException(Code) | | Retrieve setting for SO_TIMEOUT. 0 returns implies that the
option is disabled (i.e., timeout of infinity).
the SO_TIMEOUT value
exception:
IOException - if an I/O error occurs
since:
JDK1.1
See Also: ServerSocket.setSoTimeout(int) |
| implAccept | | final protected void implAccept(Socket s) throws IOException(Code) | | Subclasses of ServerSocket use this method to override accept()
to return their own subclass of socket. So a FooServerSocket
will typically hand this method an empty FooSocket. On
return from implAccept the FooSocket will be connected to a client.
Parameters:
s - the Socket
throws:
java.nio.channels.IllegalBlockingModeException - if this socket has an associated channel,and the channel is in non-blocking mode
throws:
IOException - if an I/O error occurs when waiting for a connection.
since:
JDK1.1 |
| isBound | | public boolean isBound()(Code) | | Returns the binding state of the ServerSocket.
true if the ServerSocket succesfuly bound to an address
since:
1.4 |
| isClosed | | public boolean isClosed()(Code) | | Returns the closed state of the ServerSocket.
true if the socket has been closed
since:
1.4 |
| setBound | | void setBound()(Code) | | |
| setCreated | | void setCreated()(Code) | | |
| setPerformancePreferences | | public void setPerformancePreferences(int connectionTime, int latency, int bandwidth)(Code) | | Sets performance preferences for this ServerSocket.
Sockets use the TCP/IP protocol by default. Some implementations
may offer alternative protocols which have different performance
characteristics than TCP/IP. This method allows the application to
express its own preferences as to how these tradeoffs should be made
when the implementation chooses from the available protocols.
Performance preferences are described by three integers
whose values indicate the relative importance of short connection time,
low latency, and high bandwidth. The absolute values of the integers
are irrelevant; in order to choose a protocol the values are simply
compared, with larger values indicating stronger preferences. If the
application prefers short connection time over both low latency and high
bandwidth, for example, then it could invoke this method with the values
(1, 0, 0). If the application prefers high bandwidth above low
latency, and low latency above short connection time, then it could
invoke this method with the values (0, 1, 2).
Invoking this method after this socket has been bound
will have no effect. This implies that in order to use this capability
requires the socket to be created with the no-argument constructor.
Parameters:
connectionTime - An int expressing the relative importance of a shortconnection time
Parameters:
latency - An int expressing the relative importance of lowlatency
Parameters:
bandwidth - An int expressing the relative importance of highbandwidth
since:
1.5 |
| setReceiveBufferSize | | public synchronized void setReceiveBufferSize(int size) throws SocketException(Code) | | Sets a default proposed value for the SO_RCVBUF option for sockets
accepted from this ServerSocket. The value actually set
in the accepted socket must be determined by calling
Socket.getReceiveBufferSize after the socket
is returned by
ServerSocket.accept() .
The value of SO_RCVBUF is used both to set the size of the internal
socket receive buffer, and to set the size of the TCP receive window
that is advertized to the remote peer.
It is possible to change the value subsequently, by calling
Socket.setReceiveBufferSize(int) . However, if the application
wishes to allow a receive window larger than 64K bytes, as defined by RFC1323
then the proposed value must be set in the ServerSocket before
it is bound to a local address. This implies, that the ServerSocket must be
created with the no-argument constructor, then setReceiveBufferSize() must
be called and lastly the ServerSocket is bound to an address by calling bind().
Failure to do this will not cause an error, and the buffer size may be set to the
requested value but the TCP receive window in sockets accepted from
this ServerSocket will be no larger than 64K bytes.
exception:
SocketException - if there is an errorin the underlying protocol, such as a TCP error.
Parameters:
size - the size to which to set the receive buffersize. This value must be greater than 0.
exception:
IllegalArgumentException - if the value is 0 or is negative.
since:
1.4
See Also: ServerSocket.getReceiveBufferSize |
| setReuseAddress | | public void setReuseAddress(boolean on) throws SocketException(Code) | | Enable/disable the SO_REUSEADDR socket option.
When a TCP connection is closed the connection may remain
in a timeout state for a period of time after the connection
is closed (typically known as the TIME_WAIT state
or 2MSL wait state).
For applications using a well known socket address or port
it may not be possible to bind a socket to the required
SocketAddress if there is a connection in the
timeout state involving the socket address or port.
Enabling SO_REUSEADDR prior to binding the socket
using
ServerSocket.bind(SocketAddress) allows the socket to be
bound even though a previous connection is in a timeout
state.
When a ServerSocket is created the initial setting
of SO_REUSEADDR is not defined. Applications can
use
ServerSocket.getReuseAddress() to determine the initial
setting of SO_REUSEADDR.
The behaviour when SO_REUSEADDR is enabled or
disabled after a socket is bound (See
ServerSocket.isBound() )
is not defined.
Parameters:
on - whether to enable or disable the socket option
exception:
SocketException - if an error occurs enabling ordisabling the SO_RESUEADDR socket option,or the socket is closed.
since:
1.4
See Also: ServerSocket.getReuseAddress()
See Also:
See Also: ServerSocket.bind(SocketAddress)
See Also: ServerSocket.isBound()
See Also: ServerSocket.isClosed() |
| 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 accept() for this ServerSocket
will block for only this amount of time. If the timeout expires,
a java.net.SocketTimeoutException is raised, though the
ServerSocket 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
exception:
SocketException - if there is an error in the underlying protocol, such as a TCP error.
since:
JDK1.1
See Also: ServerSocket.getSoTimeout() |
| setSocketFactory | | public static synchronized void setSocketFactory(SocketImplFactory fac) throws IOException(Code) | | Sets the server socket implementation factory for the
application. The factory can be specified only once.
When an application creates a new server socket, the socket
implementation factory's createSocketImpl method is
called to create the actual 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 thesocket factory.
exception:
SocketException - if the factory has already been defined.
exception:
SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
See Also: java.net.SocketImplFactory.createSocketImpl
See Also: SecurityManager.checkSetFactory |
| toString | | public String toString()(Code) | | Returns the implementation address and implementation port of
this socket as a String.
a string representation of this socket. |
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