public class Socket extends Object implements Closeable
This class implements client sockets (also called just "sockets"). A socket is an endpoint for communication between two machines.
The actual work of the socket is performed by an instance of the SocketImpl
class. An application, by changing the socket factory that creates the socket implementation, can configure itself to create sockets appropriate to the local firewall.
setSocketImplFactory(java.net.SocketImplFactory)
, SocketImpl
, SocketChannel
public Socket()
Creates an unconnected socket, with the system-default type of SocketImpl.
public Socket(Proxy proxy)
Creates an unconnected socket, specifying the type of proxy, if any, that should be used regardless of any other settings.
If there is a security manager, its checkConnect
method is called with the proxy host address and port number as its arguments. This could result in a SecurityException.
Examples:
Socket s = new Socket(Proxy.NO_PROXY);
will create a plain socket ignoring any other proxy configuration.Socket s = new Socket(new Proxy(Proxy.Type.SOCKS, new InetSocketAddress("socks.mydom.com", 1080)));
will create a socket connecting through the specified SOCKS proxy server.proxy
- a Proxy
object specifying what kind of proxying should be used.IllegalArgumentException
- if the proxy is of an invalid type or null
.SecurityException
- if a security manager is present and permission to connect to the proxy is denied.ProxySelector
, Proxy
protected Socket(SocketImpl impl) throws SocketException
Creates an unconnected Socket with a user-specified SocketImpl.
impl
- an instance of a SocketImpl the subclass wishes to use on the Socket.SocketException
- if there is an error in the underlying protocol, such as a TCP error.public Socket(String host, int port) throws UnknownHostException, IOException
Creates a stream socket and connects it to the specified port number on the named host.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
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 checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
host
- the host name, or null
for the loopback address.port
- the port number.UnknownHostException
- if the IP address of the host could not be determined.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.setSocketImplFactory(java.net.SocketImplFactory)
, SocketImpl
, SocketImplFactory.createSocketImpl()
, SecurityManager.checkConnect(java.lang.String, int)
public Socket(InetAddress address, int port) throws IOException
Creates a stream socket and connects it to the specified port number at the specified IP address.
If the application has specified a 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 checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
address
- the IP address.port
- the port number.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.NullPointerException
- if address
is null.setSocketImplFactory(java.net.SocketImplFactory)
, SocketImpl
, SocketImplFactory.createSocketImpl()
, SecurityManager.checkConnect(java.lang.String, int)
public Socket(String host, int port, InetAddress localAddr, int localPort) throws IOException
Creates a socket and connects it to the specified remote host on the specified remote port. The Socket will also bind() to the local address and port supplied.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
A local port number of zero
will let the system pick up a free port in the bind
operation.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
host
- the name of the remote host, or null
for the loopback address.port
- the remote portlocalAddr
- the local address the socket is bound to, or null
for the anyLocal
address.localPort
- the local port the socket is bound to, or zero
for a system selected free port.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the connection to the destination, or if its checkListen
method doesn't allow the bind to the local port.IllegalArgumentException
- if the port parameter or localPort parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.SecurityManager.checkConnect(java.lang.String, int)
public Socket(InetAddress address, int port, InetAddress localAddr, int localPort) throws IOException
Creates a socket and connects it to the specified remote address on the specified remote port. The Socket will also bind() to the local address and port supplied.
If the specified local address is null
it is the equivalent of specifying the address as the AnyLocal address (see InetAddress.isAnyLocalAddress
()
).
A local port number of zero
will let the system pick up a free port in the bind
operation.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
address
- the remote addressport
- the remote portlocalAddr
- the local address the socket is bound to, or null
for the anyLocal
address.localPort
- the local port the socket is bound to or zero
for a system selected free port.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the connection to the destination, or if its checkListen
method doesn't allow the bind to the local port.IllegalArgumentException
- if the port parameter or localPort parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.NullPointerException
- if address
is null.SecurityManager.checkConnect(java.lang.String, int)
@Deprecated public Socket(String host, int port, boolean stream) throws IOException
Deprecated. Use DatagramSocket instead for UDP transport.
Creates a stream socket and connects it to the specified port number on the named host.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
If the stream argument is true
, this creates a stream socket. If the stream argument is false
, it creates a datagram socket.
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 checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
If a UDP socket is used, TCP/IP related socket options will not apply.
host
- the host name, or null
for the loopback address.port
- the port number.stream
- a boolean
indicating whether this is a stream socket or a datagram socket.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.setSocketImplFactory(java.net.SocketImplFactory)
, SocketImpl
, SocketImplFactory.createSocketImpl()
, SecurityManager.checkConnect(java.lang.String, int)
@Deprecated public Socket(InetAddress host, int port, boolean stream) throws IOException
Deprecated. Use DatagramSocket instead for UDP transport.
Creates a socket and connects it to the specified port number at the specified IP address.
If the stream argument is true
, this creates a stream socket. If the stream argument is false
, it creates a datagram socket.
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 checkConnect
method is called with host.getHostAddress()
and port
as its arguments. This could result in a SecurityException.
If UDP socket is used, TCP/IP related socket options will not apply.
host
- the IP address.port
- the port number.stream
- if true
, create a stream socket; otherwise, create a datagram socket.IOException
- if an I/O error occurs when creating the socket.SecurityException
- if a security manager exists and its checkConnect
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.NullPointerException
- if host
is null.setSocketImplFactory(java.net.SocketImplFactory)
, SocketImpl
, SocketImplFactory.createSocketImpl()
, SecurityManager.checkConnect(java.lang.String, int)
public void connect(SocketAddress endpoint) throws IOException
Connects this socket to the server.
endpoint
- the SocketAddress
IOException
- if an error occurs during the connectionIllegalBlockingModeException
- if this socket has an associated channel, and the channel is in non-blocking modeIllegalArgumentException
- if endpoint is null or is a SocketAddress subclass not supported by this socketpublic void connect(SocketAddress endpoint, int timeout) throws IOException
Connects this socket to the server with a specified timeout value. A timeout of zero is interpreted as an infinite timeout. The connection will then block until established or an error occurs.
endpoint
- the SocketAddress
timeout
- the timeout value to be used in milliseconds.IOException
- if an error occurs during the connectionSocketTimeoutException
- if timeout expires before connectingIllegalBlockingModeException
- if this socket has an associated channel, and the channel is in non-blocking modeIllegalArgumentException
- if endpoint is null or is a SocketAddress subclass not supported by this socketpublic void bind(SocketAddress bindpoint) throws IOException
Binds the socket to a local address.
If the address is null
, then the system will pick up an ephemeral port and a valid local address to bind the socket.
bindpoint
- the SocketAddress
to bind toIOException
- if the bind operation fails, or if the socket is already bound.IllegalArgumentException
- if bindpoint is a SocketAddress subclass not supported by this socketSecurityException
- if a security manager exists and its checkListen
method doesn't allow the bind to the local port.isBound()
public InetAddress getInetAddress()
Returns the address to which the socket is connected.
If the socket was connected prior to being closed
, then this method will continue to return the connected address after the socket is closed.
null
if the socket is not connected.public InetAddress getLocalAddress()
Gets the local address to which the socket is bound.
If there is a security manager set, its checkConnect
method is called with the local address and -1
as its arguments to see if the operation is allowed. If the operation is not allowed, the loopback
address is returned.
SecurityManager.checkConnect(java.lang.String, int)
public int getPort()
Returns the remote port number to which this socket is connected.
If the socket was connected prior to being closed
, then this method will continue to return the connected port number after the socket is closed.
public int getLocalPort()
Returns the local port number to which this socket is bound.
If the socket was bound prior to being closed
, then this method will continue to return the local port number after the socket is closed.
public SocketAddress getRemoteSocketAddress()
Returns the address of the endpoint this socket is connected to, or null
if it is unconnected.
If the socket was connected prior to being closed
, then this method will continue to return the connected address after the socket is closed.
SocketAddress
representing the remote endpoint of this socket, or null
if it is not connected yet.getInetAddress()
, getPort()
, connect(SocketAddress, int)
, connect(SocketAddress)
public SocketAddress getLocalSocketAddress()
Returns the address of the endpoint this socket is bound to.
If a socket bound to an endpoint represented by an InetSocketAddress
is closed
, then this method will continue to return an InetSocketAddress
after the socket is closed. In that case the returned InetSocketAddress
's address is the wildcard
address and its port is the local port that it was bound to.
If there is a security manager set, its checkConnect
method is called with the local address and -1
as its arguments to see if the operation is allowed. If the operation is not allowed, a SocketAddress
representing the loopback
address and the local port to which this socket is bound is returned.
SocketAddress
representing the local endpoint of this socket, or a SocketAddress
representing the loopback address if denied by the security manager, or null
if the socket is not bound yet.getLocalAddress()
, getLocalPort()
, bind(SocketAddress)
, SecurityManager.checkConnect(java.lang.String, int)
public SocketChannel getChannel()
Returns the unique SocketChannel
object associated with this socket, if any.
A socket will have a channel if, and only if, the channel itself was created via the SocketChannel.open
or ServerSocketChannel.accept
methods.
null
if this socket was not created for a channelpublic InputStream getInputStream() throws IOException
Returns an input stream for this socket.
If this socket has an associated channel then the resulting input stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the input stream's read
operations will throw an IllegalBlockingModeException
.
Under abnormal conditions the underlying connection may be broken by the remote host or the network software (for example a connection reset in the case of TCP connections). When a broken connection is detected by the network software the following applies to the returned input stream :-
The network software may discard bytes that are buffered by the socket. Bytes that aren't discarded by the network software can be read using read
.
If there are no bytes buffered on the socket, or all buffered bytes have been consumed by read
, then all subsequent calls to read
will throw an IOException
.
If there are no bytes buffered on the socket, and the socket has not been closed using close
, then available
will return 0
.
Closing the returned InputStream
will close the associated socket.
IOException
- if an I/O error occurs when creating the input stream, the socket is closed, the socket is not connected, or the socket input has been shutdown using shutdownInput()
public OutputStream getOutputStream() throws IOException
Returns an output stream for this socket.
If this socket has an associated channel then the resulting output stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the output stream's write
operations will throw an IllegalBlockingModeException
.
Closing the returned OutputStream
will close the associated socket.
IOException
- if an I/O error occurs when creating the output stream or if the socket is not connected.public void setTcpNoDelay(boolean on) throws SocketException
Enable/disable TCP_NODELAY
(disable/enable Nagle's algorithm).
on
- true
to enable TCP_NODELAY, false
to disable.SocketException
- if there is an error in the underlying protocol, such as a TCP error.getTcpNoDelay()
public boolean getTcpNoDelay() throws SocketException
Tests if TCP_NODELAY
is enabled.
boolean
indicating whether or not TCP_NODELAY
is enabled.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setTcpNoDelay(boolean)
public void setSoLinger(boolean on, int linger) throws SocketException
Enable/disable SO_LINGER
with the specified linger time in seconds. The maximum timeout value is platform specific. The setting only affects socket close.
on
- whether or not to linger on.linger
- how long to linger for, if on is true.SocketException
- if there is an error in the underlying protocol, such as a TCP error.IllegalArgumentException
- if the linger value is negative.getSoLinger()
public int getSoLinger() throws SocketException
Returns setting for SO_LINGER
. -1 returns implies that the option is disabled. The setting only affects socket close.
SO_LINGER
.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setSoLinger(boolean, int)
public void sendUrgentData(int data) throws IOException
Send one byte of urgent data on the socket. The byte to be sent is the lowest eight bits of the data parameter. The urgent byte is sent after any preceding writes to the socket OutputStream and before any future writes to the OutputStream.
data
- The byte of data to sendIOException
- if there is an error sending the data.public void setOOBInline(boolean on) throws SocketException
Enable/disable SO_OOBINLINE
(receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded. If the user wishes to receive urgent data, then this option must be enabled. When enabled, urgent data is received inline with normal data.
Note, only limited support is provided for handling incoming urgent data. In particular, no notification of incoming urgent data is provided and there is no capability to distinguish between normal data and urgent data unless provided by a higher level protocol.
on
- true
to enable SO_OOBINLINE
, false
to disable.SocketException
- if there is an error in the underlying protocol, such as a TCP error.getOOBInline()
public boolean getOOBInline() throws SocketException
Tests if SO_OOBINLINE
is enabled.
boolean
indicating whether or not SO_OOBINLINE
is enabled.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setOOBInline(boolean)
public void setSoTimeout(int timeout) throws SocketException
Enable/disable SO_TIMEOUT
with the specified timeout, in milliseconds. With this option set to a non-zero timeout, a read() call on the InputStream associated with this Socket will block for only this amount of time. If the timeout expires, a java.net.SocketTimeoutException is raised, though the Socket 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.
timeout
- the specified timeout, in milliseconds.SocketException
- if there is an error in the underlying protocol, such as a TCP error.getSoTimeout()
public int getSoTimeout() throws SocketException
Returns setting for SO_TIMEOUT
. 0 returns implies that the option is disabled (i.e., timeout of infinity).
SO_TIMEOUT
SocketException
- if there is an error in the underlying protocol, such as a TCP error.setSoTimeout(int)
public void setSendBufferSize(int size) throws SocketException
Sets the SO_SNDBUF
option to the specified value for this Socket
. The SO_SNDBUF
option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.
Because SO_SNDBUF
is a hint, applications that want to verify what size the buffers were set to should call getSendBufferSize()
.
size
- the size to which to set the send buffer size. This value must be greater than 0.SocketException
- if there is an error in the underlying protocol, such as a TCP error.IllegalArgumentException
- if the value is 0 or is negative.getSendBufferSize()
public int getSendBufferSize() throws SocketException
Get value of the SO_SNDBUF
option for this Socket
, that is the buffer size used by the platform for output on this Socket
.
SO_SNDBUF
option for this Socket
.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setSendBufferSize(int)
public void setReceiveBufferSize(int size) throws SocketException
Sets the SO_RCVBUF
option to the specified value for this Socket
. The SO_RCVBUF
option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.
Increasing the receive buffer size can increase the performance of network I/O for high-volume connection, while decreasing it can help reduce the backlog of incoming data.
Because SO_RCVBUF
is a hint, applications that want to verify what size the buffers were set to should call getReceiveBufferSize()
.
The value of SO_RCVBUF
is also used to set the TCP receive window that is advertized to the remote peer. Generally, the window size can be modified at any time when a socket is connected. However, if a receive window larger than 64K is required then this must be requested before the socket is connected to the remote peer. There are two cases to be aware of:
ServerSocket.setReceiveBufferSize(int)
before the ServerSocket is bound to a local address.
size
- the size to which to set the receive buffer size. This value must be greater than 0.IllegalArgumentException
- if the value is 0 or is negative.SocketException
- if there is an error in the underlying protocol, such as a TCP error.getReceiveBufferSize()
, ServerSocket.setReceiveBufferSize(int)
public int getReceiveBufferSize() throws SocketException
Gets the value of the SO_RCVBUF
option for this Socket
, that is the buffer size used by the platform for input on this Socket
.
SO_RCVBUF
option for this Socket
.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setReceiveBufferSize(int)
public void setKeepAlive(boolean on) throws SocketException
Enable/disable SO_KEEPALIVE
.
on
- whether or not to have socket keep alive turned on.SocketException
- if there is an error in the underlying protocol, such as a TCP error.getKeepAlive()
public boolean getKeepAlive() throws SocketException
Tests if SO_KEEPALIVE
is enabled.
boolean
indicating whether or not SO_KEEPALIVE
is enabled.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setKeepAlive(boolean)
public void setTrafficClass(int tc) throws SocketException
Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket. 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)
Setting bits in the precedence field may result in a SocketException indicating that the operation is not permitted.
As RFC 1122 section 4.2.4.2 indicates, a compliant TCP implementation should, but is not required to, let application change the TOS field during the lifetime of a connection. So whether the type-of-service field can be changed after the TCP connection has been established depends on the implementation in the underlying platform. Applications should not assume that they can change the TOS field after the connection.
For Internet Protocol v6 tc
is the value that would be placed into the sin6_flowinfo field of the IP header.
tc
- an int
value for the bitset.SocketException
- if there is an error setting the traffic class or type-of-servicegetTrafficClass()
, SocketOptions.IP_TOS
public int getTrafficClass() throws SocketException
Gets traffic class or type-of-service in the IP header for packets sent from this Socket
As the underlying network implementation may ignore the traffic class or type-of-service set using setTrafficClass(int)
this method may return a different value than was previously set using the setTrafficClass(int)
method on this Socket.
SocketException
- if there is an error obtaining the traffic class or type-of-service value.setTrafficClass(int)
, SocketOptions.IP_TOS
public void setReuseAddress(boolean on) throws SocketException
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 bind(SocketAddress)
allows the socket to be bound even though a previous connection is in a timeout state.
When a Socket
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 isBound()
) is not defined.
on
- whether to enable or disable the socket optionSocketException
- if an error occurs enabling or disabling the SO_REUSEADDR
socket option, or the socket is closed.getReuseAddress()
, bind(SocketAddress)
, isClosed()
, isBound()
public boolean getReuseAddress() throws SocketException
Tests if SO_REUSEADDR
is enabled.
boolean
indicating whether or not SO_REUSEADDR
is enabled.SocketException
- if there is an error in the underlying protocol, such as a TCP error.setReuseAddress(boolean)
public void close() throws IOException
Closes this socket.
Any thread currently blocked in an I/O operation upon this socket will throw a SocketException
.
Once a socket has been closed, it is not available for further networking use (i.e. can't be reconnected or rebound). A new socket needs to be created.
Closing this socket will also close the socket's InputStream
and OutputStream
.
If this socket has an associated channel then the channel is closed as well.
close
in interface Closeable
close
in interface AutoCloseable
IOException
- if an I/O error occurs when closing this socket.isClosed()
public void shutdownInput() throws IOException
Places the input stream for this socket at "end of stream". Any data sent to the input stream side of the socket is acknowledged and then silently discarded.
If you read from a socket input stream after invoking this method on the socket, the stream's available
method will return 0, and its read
methods will return -1
(end of stream).
IOException
- if an I/O error occurs when shutting down this socket.shutdownOutput()
, close()
, setSoLinger(boolean, int)
, isInputShutdown()
public void shutdownOutput() throws IOException
Disables the output stream for this socket. For a TCP socket, any previously written data will be sent followed by TCP's normal connection termination sequence. If you write to a socket output stream after invoking shutdownOutput() on the socket, the stream will throw an IOException.
IOException
- if an I/O error occurs when shutting down this socket.shutdownInput()
, close()
, setSoLinger(boolean, int)
, isOutputShutdown()
public String toString()
Converts this socket to a String
.
public boolean isConnected()
Returns the connection state of the socket.
Note: Closing a socket doesn't clear its connection state, which means this method will return true
for a closed socket (see isClosed()
) if it was successfuly connected prior to being closed.
public boolean isBound()
Returns the binding state of the socket.
Note: Closing a socket doesn't clear its binding state, which means this method will return true
for a closed socket (see isClosed()
) if it was successfuly bound prior to being closed.
bind(java.net.SocketAddress)
public boolean isClosed()
Returns the closed state of the socket.
close()
public boolean isInputShutdown()
Returns whether the read-half of the socket connection is closed.
shutdownInput()
public boolean isOutputShutdown()
Returns whether the write-half of the socket connection is closed.
shutdownOutput()
public static void setSocketImplFactory(SocketImplFactory fac) throws IOException
Sets the client socket implementation factory for the application. The factory can be specified only once.
When an application creates a new client 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.
fac
- the desired factory.IOException
- if an I/O error occurs when setting the socket factory.SocketException
- if the factory is already defined.SecurityException
- if a security manager exists and its checkSetFactory
method doesn't allow the operation.SocketImplFactory.createSocketImpl()
, SecurityManager.checkSetFactory()
public void setPerformancePreferences(int connectionTime, int latency, int bandwidth)
Sets performance preferences for this socket.
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. Negative values represent a lower priority than positive values. 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 connected will have no effect.
connectionTime
- An int
expressing the relative importance of a short connection timelatency
- An int
expressing the relative importance of low latencybandwidth
- An int
expressing the relative importance of high bandwidth
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.