Package org.apache.commons.net

Class DatagramSocketClient

  • Direct Known Subclasses:
    CharGenUDPClient, DaytimeUDPClient, DiscardUDPClient, NTPUDPClient, TFTP, TimeUDPClient
    public abstract class DatagramSocketClient
extends java.lang.Object
    The DatagramSocketClient provides the basic operations that are required of client objects accessing datagram sockets. It is meant to be subclassed to avoid having to rewrite the same code over and over again to open a socket, close a socket, set timeouts, etc. Of special note is the setDatagramSocketFactory method, which allows you to control the type of DatagramSocket the DatagramSocketClient creates for network communications. This is especially useful for adding things like proxy support as well as better support for applets. For example, you could create a DatagramSocketFactory that requests browser security capabilities before creating a socket. All classes derived from DatagramSocketClient should use the _socketFactory_ member variable to create DatagramSocket instances rather than instantiating them by directly invoking a constructor. By honoring this contract you guarantee that a user will always be able to provide his own Socket implementations by substituting his own SocketFactory.
    See Also:
    DatagramSocketFactory

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected boolean _isOpen_
      A status variable indicating if the client's socket is currently open.
      protected java.net.DatagramSocket _socket_
      The datagram socket used for the connection.
      protected DatagramSocketFactory _socketFactory_
      The datagram socket's DatagramSocketFactory.
      protected int _timeout_
      The timeout to use after opening a socket.

    • Constructor Summary

      Constructors 
      Constructor Description
      DatagramSocketClient()
      Default constructor for DatagramSocketClient.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Closes the DatagramSocket used for the connection.
      java.nio.charset.Charset getCharset()
      Gets the charset.
      java.lang.String getCharsetName()
      Gets the charset name.
      int getDefaultTimeout()
      Returns the default timeout in milliseconds that is used when opening a socket.
      java.net.InetAddress getLocalAddress()
      Returns the local address to which the client's socket is bound.
      int getLocalPort()
      Returns the port number of the open socket on the local host used for the connection.
      int getSoTimeout()
      Returns the timeout in milliseconds of the currently opened socket.
      boolean isOpen()
      Returns true if the client has a currently open socket.
      void open()
      Opens a DatagramSocket on the local host at the first available port.
      void open​(int port)
      Opens a DatagramSocket on the local host at a specified port.
      void open​(int port, java.net.InetAddress laddr)
      Opens a DatagramSocket at the specified address on the local host at a specified port.
      void setCharset​(java.nio.charset.Charset charset)
      Sets the charset.
      void setDatagramSocketFactory​(DatagramSocketFactory factory)
      Sets the DatagramSocketFactory used by the DatagramSocketClient to open DatagramSockets.
      void setDefaultTimeout​(int timeout)
      Set the default timeout in milliseconds to use when opening a socket.
      void setSoTimeout​(int timeout)
      Set the timeout in milliseconds of a currently open connection.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • _timeout_

        protected int _timeout_
        The timeout to use after opening a socket.

      • _socket_

        protected java.net.DatagramSocket _socket_
        The datagram socket used for the connection.

      • _isOpen_

        protected boolean _isOpen_
        A status variable indicating if the client's socket is currently open.

      • _socketFactory_

        protected DatagramSocketFactory _socketFactory_
        The datagram socket's DatagramSocketFactory.

    • Constructor Detail

      • DatagramSocketClient

        public DatagramSocketClient()
        Default constructor for DatagramSocketClient. Initializes _socket_ to null, _timeout_ to 0, and _isOpen_ to false.

    • Method Detail

      • open

        public void open()
          throws java.net.SocketException
        Opens a DatagramSocket on the local host at the first available port. Also sets the timeout on the socket to the default timeout set by setDefaultTimeout() .

        _isOpen_ is set to true after calling this method and _socket_ is set to the newly opened socket.

        Throws:
        java.net.SocketException - If the socket could not be opened or the timeout could not be set.

      • open

        public void open​(int port)
          throws java.net.SocketException
        Opens a DatagramSocket on the local host at a specified port. Also sets the timeout on the socket to the default timeout set by setDefaultTimeout() .

        _isOpen_ is set to true after calling this method and _socket_ is set to the newly opened socket.

        Parameters:
        port - The port to use for the socket.
        Throws:
        java.net.SocketException - If the socket could not be opened or the timeout could not be set.

      • open

        public void open​(int port,
                 java.net.InetAddress laddr)
          throws java.net.SocketException
        Opens a DatagramSocket at the specified address on the local host at a specified port. Also sets the timeout on the socket to the default timeout set by setDefaultTimeout() .

        _isOpen_ is set to true after calling this method and _socket_ is set to the newly opened socket.

        Parameters:
        port - The port to use for the socket.
        laddr - The local address to use.
        Throws:
        java.net.SocketException - If the socket could not be opened or the timeout could not be set.

      • close

        public void close()
        Closes the DatagramSocket used for the connection. You should call this method after you've finished using the class instance and also before you call open() again. _isOpen_ is set to false and _socket_ is set to null.

      • isOpen

        public boolean isOpen()
        Returns true if the client has a currently open socket.
        Returns:
        True if the client has a currently open socket, false otherwise.

      • setDefaultTimeout

        public void setDefaultTimeout​(int timeout)
        Set the default timeout in milliseconds to use when opening a socket. After a call to open, the timeout for the socket is set using this value. This method should be used prior to a call to open() and should not be confused with setSoTimeout() which operates on the currently open socket. _timeout_ contains the new timeout value.
        Parameters:
        timeout - The timeout in milliseconds to use for the datagram socket connection.

      • getDefaultTimeout

        public int getDefaultTimeout()
        Returns the default timeout in milliseconds that is used when opening a socket.
        Returns:
        The default timeout in milliseconds that is used when opening a socket.

      • setSoTimeout

        public void setSoTimeout​(int timeout)
                  throws java.net.SocketException
        Set the timeout in milliseconds of a currently open connection. Only call this method after a connection has been opened by open().
        Parameters:
        timeout - The timeout in milliseconds to use for the currently open datagram socket connection.
        Throws:
        java.net.SocketException - if an error setting the timeout

      • getSoTimeout

        public int getSoTimeout()
                 throws java.net.SocketException
        Returns the timeout in milliseconds of the currently opened socket. If you call this method when the client socket is not open, a NullPointerException is thrown.
        Returns:
        The timeout in milliseconds of the currently opened socket.
        Throws:
        java.net.SocketException - if an error getting the timeout

      • getLocalPort

        public int getLocalPort()
        Returns the port number of the open socket on the local host used for the connection. If you call this method when the client socket is not open, a NullPointerException is thrown.
        Returns:
        The port number of the open socket on the local host used for the connection.

      • getLocalAddress

        public java.net.InetAddress getLocalAddress()
        Returns the local address to which the client's socket is bound. If you call this method when the client socket is not open, a NullPointerException is thrown.
        Returns:
        The local address to which the client's socket is bound.

      • setDatagramSocketFactory

        public void setDatagramSocketFactory​(DatagramSocketFactory factory)
        Sets the DatagramSocketFactory used by the DatagramSocketClient to open DatagramSockets. If the factory value is null, then a default factory is used (only do this to reset the factory after having previously altered it).
        Parameters:
        factory - The new DatagramSocketFactory the DatagramSocketClient should use.

      • getCharsetName

        public java.lang.String getCharsetName()
        Gets the charset name.
        Returns:
        the charset name.
        Since:
        3.3 TODO Will be deprecated once the code requires Java 1.6 as a mininmum

      • getCharset

        public java.nio.charset.Charset getCharset()
        Gets the charset.
        Returns:
        the charset.
        Since:
        3.3

      • setCharset

        public void setCharset​(java.nio.charset.Charset charset)
        Sets the charset.
        Parameters:
        charset - the charset.
        Since:
        3.3