Class SocketImpl
- All Implemented Interfaces:
SocketOptions
SocketImpl
is a common superclass
of all classes that actually implement sockets. It is used to
create both client and server sockets.- Since:
- 1.0
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Field Summary
Modifier and TypeFieldDescriptionprotected InetAddress
The IP address of the remote end of this socket.protected FileDescriptor
The file descriptor object for this socket.protected int
The local port number to which this socket is connected.protected int
The port number on the remote host to which this socket is connected.Fields declared in interface java.net.SocketOptions
IP_MULTICAST_IF, IP_MULTICAST_IF2, IP_MULTICAST_LOOP, IP_TOS, SO_BINDADDR, SO_BROADCAST, SO_KEEPALIVE, SO_LINGER, SO_OOBINLINE, SO_RCVBUF, SO_REUSEADDR, SO_REUSEPORT, SO_SNDBUF, SO_TIMEOUT, TCP_NODELAY
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionprotected abstract void
accept
(SocketImpl s) Accepts a connection.protected abstract int
Returns the number of bytes that can be read from this socket without blocking.protected abstract void
bind
(InetAddress host, int port) Binds this socket to the specified local IP address and port number.protected abstract void
close()
Closes this socket.protected abstract void
Connects this socket to the specified port on the named host.protected abstract void
connect
(InetAddress address, int port) Connects this socket to the specified port number on the specified host.protected abstract void
connect
(SocketAddress address, int timeout) Connects this socket to the specified port number on the specified host.protected abstract void
create
(boolean stream) Creates either a stream or a datagram socket.protected FileDescriptor
Returns the value of this socket'sfd
field.protected InetAddress
Returns the value of this socket'saddress
field.protected abstract InputStream
Returns an input stream for this socket.protected int
Returns the value of this socket'slocalport
field.protected <T> T
getOption
(SocketOption<T> name) Called to get a socket option.protected abstract OutputStream
Returns an output stream for this socket.protected int
getPort()
Returns the value of this socket'sport
field.protected abstract void
listen
(int backlog) Sets the maximum queue length for incoming connection indications (a request to connect) to thecount
argument.protected abstract void
sendUrgentData
(int data) Send one byte of urgent data on the socket.protected <T> void
setOption
(SocketOption<T> name, T value) Called to set a socket option.protected void
setPerformancePreferences
(int connectionTime, int latency, int bandwidth) Sets performance preferences for this socket.protected void
Places the input stream for this socket at "end of stream".protected void
Disables the output stream for this socket.protected Set
<SocketOption<?>> Returns a set of SocketOptions supported by this impl and by this impl's socket (Socket or ServerSocket)protected boolean
Returns whether or not this SocketImpl supports sending urgent data.toString()
Returns the address and port of this socket as aString
.Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods declared in interface java.net.SocketOptions
getOption, setOption
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Field Details
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fd
The file descriptor object for this socket. -
address
The IP address of the remote end of this socket. -
port
protected int portThe port number on the remote host to which this socket is connected. -
localport
protected int localportThe local port number to which this socket is connected.
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Constructor Details
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SocketImpl
public SocketImpl()Initialize a new instance of this class
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Method Details
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create
Creates either a stream or a datagram socket.- API Note:
- The
Socket
constructors to create a datagram socket are deprecated for removal. This method will be re-specified in a future release to not support creating datagram sockets. - Parameters:
stream
- iftrue
, create a stream socket; otherwise, create a datagram socket.- Throws:
IOException
- if an I/O error occurs while creating the socket.
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connect
Connects this socket to the specified port on the named host.- Parameters:
host
- the name of the remote host.port
- the port number.- Throws:
IOException
- if an I/O error occurs when connecting to the remote host.
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connect
Connects this socket to the specified port number on the specified host.- Parameters:
address
- the IP address of the remote host.port
- the port number.- Throws:
IOException
- if an I/O error occurs when attempting a connection.
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connect
Connects this socket to the specified port number on the specified host. A timeout of zero is interpreted as an infinite timeout. The connection will then block until established or an error occurs.- Parameters:
address
- the Socket address of the remote host.timeout
- the timeout value, in milliseconds, or zero for no timeout.- Throws:
IOException
- if an I/O error occurs when attempting a connection.- Since:
- 1.4
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bind
Binds this socket to the specified local IP address and port number.- Parameters:
host
- an IP address that belongs to a local interface.port
- the port number.- Throws:
IOException
- if an I/O error occurs when binding this socket.
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listen
Sets the maximum queue length for incoming connection indications (a request to connect) to thecount
argument. If a connection indication arrives when the queue is full, the connection is refused.- Parameters:
backlog
- the maximum length of the queue.- Throws:
IOException
- if an I/O error occurs when creating the queue.
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accept
Accepts a connection.- Parameters:
s
- the accepted connection.- Throws:
IOException
- if an I/O error occurs when accepting the connection.
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getInputStream
Returns an input stream for this socket.- Returns:
- a stream for reading from this socket.
- Throws:
IOException
- if an I/O error occurs when creating the input stream.
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getOutputStream
Returns an output stream for this socket.- Returns:
- an output stream for writing to this socket.
- Throws:
IOException
- if an I/O error occurs when creating the output stream.
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available
Returns the number of bytes that can be read from this socket without blocking.- Returns:
- the number of bytes that can be read from this socket without blocking.
- Throws:
IOException
- if an I/O error occurs when determining the number of bytes available.
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close
Closes this socket.- Throws:
IOException
- if an I/O error occurs when closing this socket.
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shutdownInput
Places the input stream for this socket at "end of stream". Any data sent to this socket is acknowledged and then silently discarded. If you read from a socket input stream after invoking this method on the socket, the stream'savailable
method will return 0, and itsread
methods will return-1
(end of stream).- Throws:
IOException
- if an I/O error occurs when shutting down this socket.- Since:
- 1.3
- See Also:
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shutdownOutput
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.- Throws:
IOException
- if an I/O error occurs when shutting down this socket.- Since:
- 1.3
- See Also:
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getFileDescriptor
Returns the value of this socket'sfd
field.- Returns:
- the value of this socket's
fd
field. - See Also:
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getInetAddress
Returns the value of this socket'saddress
field.- Returns:
- the value of this socket's
address
field. - See Also:
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getPort
protected int getPort()Returns the value of this socket'sport
field.- Returns:
- the value of this socket's
port
field. - See Also:
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supportsUrgentData
protected boolean supportsUrgentData()Returns whether or not this SocketImpl supports sending urgent data. By default, false is returned unless the method is overridden in a sub-class- Returns:
- true if urgent data supported
- Since:
- 1.4
- See Also:
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sendUrgentData
Send one byte of urgent data on the socket. The byte to be sent is the low eight bits of the parameter- Parameters:
data
- The byte of data to send- Throws:
IOException
- if there is an error sending the data.- Since:
- 1.4
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getLocalPort
protected int getLocalPort()Returns the value of this socket'slocalport
field.- Returns:
- the value of this socket's
localport
field. - See Also:
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toString
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setPerformancePreferences
protected 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)
. By default, this method does nothing, unless it is overridden in a sub-class.- Parameters:
connectionTime
- Anint
expressing the relative importance of a short connection timelatency
- Anint
expressing the relative importance of low latencybandwidth
- Anint
expressing the relative importance of high bandwidth- Since:
- 1.5
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setOption
Called to set a socket option.- Implementation Requirements:
- The default implementation of this method first checks that the given
socket option
name
is not null, then throwsUnsupportedOperationException
. Subclasses should override this method with an appropriate implementation. - Type Parameters:
T
- The type of the socket option value- Parameters:
name
- The socket optionvalue
- The value of the socket option. A value ofnull
may be valid for some options.- Throws:
UnsupportedOperationException
- if the SocketImpl does not support the optionIllegalArgumentException
- if the value is not valid for the optionIOException
- if an I/O error occurs, or if the socket is closedNullPointerException
- if name isnull
- Since:
- 9
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getOption
Called to get a socket option.- Implementation Requirements:
- The default implementation of this method first checks that the given
socket option
name
is not null, then throwsUnsupportedOperationException
. Subclasses should override this method with an appropriate implementation. - Type Parameters:
T
- The type of the socket option value- Parameters:
name
- The socket option- Returns:
- the value of the named option
- Throws:
UnsupportedOperationException
- if the SocketImpl does not support the optionIOException
- if an I/O error occurs, or if the socket is closedNullPointerException
- if name isnull
- Since:
- 9
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supportedOptions
Returns a set of SocketOptions supported by this impl and by this impl's socket (Socket or ServerSocket)- Implementation Requirements:
- The default implementation of this method returns an empty set. Subclasses should override this method with an appropriate implementation.
- Returns:
- a Set of SocketOptions
- Since:
- 9
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