Package java.net

Class Socket

    • Constructor Detail

      • Socket

        public Socket()
        Creates a new unconnected socket. When a SocketImplFactory is defined it creates the internal socket implementation, otherwise the default socket implementation will be used for this socket.
        See Also:
        SocketImplFactory, SocketImpl

      • Socket

        public Socket​(Proxy proxy)
        Creates a new unconnected socket using the given proxy type. When a SocketImplFactory is defined it creates the internal socket implementation, otherwise the default socket implementation will be used for this socket.

        Example that will create a socket connection through a SOCKS proxy server:
        Socket sock = new Socket(new Proxy(Proxy.Type.SOCKS, new InetSocketAddress("test.domain.org", 2130)));

        Parameters:
        proxy - the specified proxy for this socket.
        Throws:
        IllegalArgumentException - if the argument proxy is null or of an invalid type.
        See Also:
        SocketImplFactory, SocketImpl

      • Socket

        public Socket​(String dstName,
              int dstPort)
       throws UnknownHostException,
              IOException
        Creates a new streaming socket connected to the target host specified by the parameters dstName and dstPort. The socket is bound to any available port on the local host.

        This implementation tries each IP address for the given hostname (in RFC 3484 order) until it either connects successfully or it exhausts the set.

        Parameters:
        dstName - the target host name or IP address to connect to.
        dstPort - the port on the target host to connect to.
        Throws:
        UnknownHostException - if the host name could not be resolved into an IP address.
        IOException - if an error occurs while creating the socket.

      • Socket

        public Socket​(String dstName,
              int dstPort,
              InetAddress localAddress,
              int localPort)
       throws IOException
        Creates a new streaming socket connected to the target host specified by the parameters dstName and dstPort. On the local endpoint the socket is bound to the given address localAddress on port localPort. If host is null a loopback address is used to connect to.

        This implementation tries each IP address for the given hostname (in RFC 3484 order) until it either connects successfully or it exhausts the set.

        Parameters:
        dstName - the target host name or IP address to connect to.
        dstPort - the port on the target host to connect to.
        localAddress - the address on the local host to bind to.
        localPort - the port on the local host to bind to.
        Throws:
        UnknownHostException - if the host name could not be resolved into an IP address.
        IOException - if an error occurs while creating the socket.

      • Socket

        @Deprecated
public Socket​(String hostName,
              int port,
              boolean streaming)
       throws IOException
        Deprecated.
        Use Socket(String, int) instead of this for streaming sockets or an appropriate constructor of DatagramSocket for UDP transport.
        Creates a new streaming or datagram socket connected to the target host specified by the parameters hostName and port. The socket is bound to any available port on the local host.

        This implementation tries each IP address for the given hostname (in RFC 3484 order) until it either connects successfully or it exhausts the set.

        Parameters:
        hostName - the target host name or IP address to connect to.
        port - the port on the target host to connect to.
        streaming - if true a streaming socket is returned, a datagram socket otherwise.
        Throws:
        UnknownHostException - if the host name could not be resolved into an IP address.
        IOException - if an error occurs while creating the socket.

      • Socket

        public Socket​(InetAddress dstAddress,
              int dstPort)
       throws IOException
        Creates a new streaming socket connected to the target host specified by the parameters dstAddress and dstPort. The socket is bound to any available port on the local host using a wildcard address.
        Parameters:
        dstAddress - the target host address to connect to.
        dstPort - the port on the target host to connect to.
        Throws:
        IOException - if an error occurs while creating the socket.

      • Socket

        public Socket​(InetAddress dstAddress,
              int dstPort,
              InetAddress localAddress,
              int localPort)
       throws IOException
        Creates a new streaming socket connected to the target host specified by the parameters dstAddress and dstPort.

        On the local endpoint the socket is bound to the given address localAddress on port localPort. If localAddress is null the socket will be bound to a wildcard address.

        Parameters:
        dstAddress - the target host address to connect to.
        dstPort - the port on the target host to connect to.
        localAddress - the address on the local host to bind to, or null.
        localPort - the port on the local host to bind to.
        Throws:
        IOException - if an error occurs while creating the socket.

      • Socket

        @Deprecated
public Socket​(InetAddress addr,
              int port,
              boolean streaming)
       throws IOException
        Deprecated.
        Use Socket(InetAddress, int) instead of this for streaming sockets or an appropriate constructor of DatagramSocket for UDP transport.
        Creates a new streaming or datagram socket connected to the target host specified by the parameters addr and port. The socket is bound to any available port on the local host using a wildcard address.
        Parameters:
        addr - the Internet address to connect to.
        port - the port on the target host to connect to.
        streaming - if true a streaming socket is returned, a datagram socket otherwise.
        Throws:
        IOException - if an error occurs while creating the socket.

      • Socket

        protected Socket​(SocketImpl impl)
          throws SocketException
        Creates an unconnected socket with the given socket implementation.
        Parameters:
        impl - the socket implementation to be used.
        Throws:
        SocketException - if an error occurs while creating the socket.

    • Method Detail

      • close

        public void close()
           throws IOException
        Closes the socket. It is not possible to reconnect or rebind to this socket thereafter which means a new socket instance has to be created.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Throws:
        IOException - if an error occurs while closing the socket.

      • onClose

        public void onClose()
        Sets the Socket and its related SocketImpl state as if a successful close() took place, without actually performing an OS close().

      • getInetAddress

        public InetAddress getInetAddress()
        Returns the IP address of the target host this socket is connected to, or null if this socket is not yet connected.

      • getInputStream

        public InputStream getInputStream()
                           throws IOException
        Returns an input stream to read data from this socket. If the socket has an associated SocketChannel and that channel is in non-blocking mode then reads from the stream will throw a IllegalBlockingModeException.
        Returns:
        the byte-oriented input stream.
        Throws:
        IOException - if an error occurs while creating the input stream or the socket is in an invalid state.

      • getLocalAddress

        public InetAddress getLocalAddress()
        Returns the local IP address this socket is bound to, or an address for which InetAddress.isAnyLocalAddress() returns true if the socket is closed or unbound.

      • getLocalPort

        public int getLocalPort()
        Returns the local port this socket is bound to, or -1 if the socket is unbound. If the socket has been closed this method will still return the local port the socket was bound to.

      • getOutputStream

        public OutputStream getOutputStream()
                             throws IOException
        Returns an output stream to write data into this socket. If the socket has an associated SocketChannel and that channel is in non-blocking mode then writes to the stream will throw a IllegalBlockingModeException.
        Returns:
        the byte-oriented output stream.
        Throws:
        IOException - if an error occurs while creating the output stream or the socket is in an invalid state.

      • getPort

        public int getPort()
        Returns the port number of the target host this socket is connected to, or 0 if this socket is not yet connected.

      • getSoLinger

        public int getSoLinger()
                throws SocketException
        Returns this socket's linger timeout in seconds, or -1 for no linger (i.e. close will return immediately).
        Throws:
        SocketException

      • getTcpNoDelay

        public boolean getTcpNoDelay()
                      throws SocketException
        Returns this socket's SocketOptions#TCP_NODELAY setting.
        Throws:
        SocketException

      • setSocketImplFactory

        public static void setSocketImplFactory​(SocketImplFactory fac)
                                 throws IOException
        Sets the internal factory for creating socket implementations. This may only be executed once during the lifetime of the application.
        Parameters:
        fac - the socket implementation factory to be set.
        Throws:
        IOException - if the factory has been already set.

      • setSoLinger

        public void setSoLinger​(boolean on,
                        int timeout)
                 throws SocketException
        Sets this socket's linger timeout in seconds. If on is false, timeout is irrelevant.
        Throws:
        SocketException

      • setSoTimeout

        public void setSoTimeout​(int timeout)
                  throws SocketException
        Sets this socket's read timeout in milliseconds. Use 0 for no timeout. To take effect, this option must be set before the blocking method was called.
        Throws:
        SocketException

      • toString

        public String toString()
        Returns a String containing a concise, human-readable description of the socket.
        Overrides:
        toString in class Object
        Returns:
        the textual representation of this socket.

      • shutdownInput

        public void shutdownInput()
                   throws IOException
        Closes the input stream of this socket. Any further data sent to this socket will be discarded. Reading from this socket after this method has been called will return the value EOF.
        Throws:
        IOException - if an error occurs while closing the socket input stream.
        SocketException - if the input stream is already closed.

      • shutdownOutput

        public void shutdownOutput()
                    throws IOException
        Closes the output stream of this socket. All buffered data will be sent followed by the termination sequence. Writing to the closed output stream will cause an IOException.
        Throws:
        IOException - if an error occurs while closing the socket output stream.
        SocketException - if the output stream is already closed.

      • getLocalSocketAddress

        public SocketAddress getLocalSocketAddress()
        Returns the local address and port of this socket as a SocketAddress or null if the socket has never been bound. If the socket is closed but has previously been bound then an address for which InetAddress.isAnyLocalAddress() returns true will be returned with the previously-bound port. This is useful on multihomed hosts.

      • getRemoteSocketAddress

        public SocketAddress getRemoteSocketAddress()
        Returns the remote address and port of this socket as a SocketAddress or null if the socket is not connected.
        Returns:
        the remote socket address and port.

      • isBound

        public boolean isBound()
        Returns whether this socket is bound to a local address and port.
        Returns:
        true if the socket is bound to a local address, false otherwise.

      • isConnected

        public boolean isConnected()
        Returns whether this socket is connected to a remote host.
        Returns:
        true if the socket is connected, false otherwise.

      • isClosed

        public boolean isClosed()
        Returns whether this socket is closed.
        Returns:
        true if the socket is closed, false otherwise.

      • bind

        public void bind​(SocketAddress localAddr)
          throws IOException
        Binds this socket to the given local host address and port specified by the SocketAddress localAddr. If localAddr is set to null, this socket will be bound to an available local address on any free port.
        Parameters:
        localAddr - the specific address and port on the local machine to bind to.
        Throws:
        IllegalArgumentException - if the given SocketAddress is invalid or not supported.
        IOException - if the socket is already bound or an error occurs while binding.

      • onBind

        public void onBind​(InetAddress localAddress,
                   int localPort)
        Sets the Socket and its related SocketImpl state as if a successful bind() took place, without actually performing an OS bind().

      • connect

        public void connect​(SocketAddress remoteAddr)
             throws IOException
        Connects this socket to the given remote host address and port specified by the SocketAddress remoteAddr.
        Parameters:
        remoteAddr - the address and port of the remote host to connect to.
        Throws:
        IllegalArgumentException - if the given SocketAddress is invalid or not supported.
        IOException - if the socket is already connected or an error occurs while connecting.

      • connect

        public void connect​(SocketAddress remoteAddr,
                    int timeout)
             throws IOException
        Connects this socket to the given remote host address and port specified by the SocketAddress remoteAddr with the specified timeout. The connecting method will block until the connection is established or an error occurred.
        Parameters:
        remoteAddr - the address and port of the remote host to connect to.
        timeout - the timeout value in milliseconds or 0 for an infinite timeout.
        Throws:
        IllegalArgumentException - if the given SocketAddress is invalid or not supported or the timeout value is negative.
        IOException - if the socket is already connected or an error occurs while connecting.

      • onConnect

        public void onConnect​(InetAddress remoteAddress,
                      int remotePort)
        Sets the Socket and its related SocketImpl state as if a successful connect() took place, without actually performing an OS connect().

      • isInputShutdown

        public boolean isInputShutdown()
        Returns whether the incoming channel of the socket has already been closed.
        Returns:
        true if reading from this socket is not possible anymore, false otherwise.

      • isOutputShutdown

        public boolean isOutputShutdown()
        Returns whether the outgoing channel of the socket has already been closed.
        Returns:
        true if writing to this socket is not possible anymore, false otherwise.

      • getTrafficClass

        public int getTrafficClass()
                    throws SocketException
        Returns this socket's {@see SocketOptions#IP_TOS} setting.
        Throws:
        SocketException

      • sendUrgentData

        public void sendUrgentData​(int value)
                    throws IOException
        Sends the given single byte data which is represented by the lowest octet of value as "TCP urgent data".
        Parameters:
        value - the byte of urgent data to be sent.
        Throws:
        IOException - if an error occurs while sending urgent data.

      • getChannel

        public SocketChannel getChannel()
        Returns this socket's SocketChannel, if one exists. A channel is available only if this socket wraps a channel. (That is, you can go from a channel to a socket and back again, but you can't go from an arbitrary socket to a channel.) In practice, this means that the socket must have been created by ServerSocketChannel.accept() or SocketChannel.open().

      • setPerformancePreferences

        public void setPerformancePreferences​(int connectionTime,
                                      int latency,
                                      int bandwidth)
        Sets performance preferences for connectionTime, latency and bandwidth.

        This method does currently nothing.

        Parameters:
        connectionTime - the value representing the importance of a short connecting time.
        latency - the value representing the importance of low latency.
        bandwidth - the value representing the importance of high bandwidth.