Package org.apache.commons.net

Class DatagramSocketClient

java.lang.Object
org.apache.commons.net.DatagramSocketClient
All Implemented Interfaces:
AutoCloseable
Direct Known Subclasses:
CharGenUDPClient, DaytimeUDPClient, DiscardUDPClient, NTPUDPClient, TFTP, TimeUDPClient
public abstract class DatagramSocketClient extends Object implements AutoCloseable
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:

  • Field Details

    • _timeout_

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

    • _socket_

      protected 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 Details

    • DatagramSocketClient

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

  • Method Details

    • checkOpen

      protected DatagramSocket checkOpen()
      Gets the non-null DatagramSocket or throws NullPointerException.

      This method does not allocate resources.

      Returns:
      the non-null DatagramSocket.
      Since:
      3.10.0

    • 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.
      Specified by:
      close in interface AutoCloseable

    • getCharset

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

    • getCharsetName

      @Deprecated public String getCharsetName()
      Deprecated.
      Use getCharset() instead
      Gets the charset name.
      Returns:
      the charset name.
      Since:
      3.3

    • getDefaultTimeout

      public int getDefaultTimeout()
      Gets 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.

    • getLocalAddress

      public InetAddress getLocalAddress()
      Gets 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.

    • getLocalPort

      public int getLocalPort()
      Gets 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.

    • getSoTimeout

      @Deprecated public int getSoTimeout() throws SocketException
      Deprecated.
      Use getSoTimeoutDuration().
      Gets 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:
      SocketException - if an error getting the timeout.

    • getSoTimeoutDuration

      public Duration getSoTimeoutDuration() throws SocketException
      Gets the timeout duration 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:
      SocketException - if an error getting the timeout.

    • isOpen

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

    • open

      public void open() throws 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:
      SocketException - If the socket could not be opened or the timeout could not be set.

    • open

      public void open(int port) throws 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:
      SocketException - If the socket could not be opened or the timeout could not be set.

    • open

      public void open(int port, InetAddress localAddress) throws 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.
      localAddress - The local address to use.
      Throws:
      SocketException - If the socket could not be opened or the timeout could not be set.

    • setCharset

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

    • 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.

    • setDefaultTimeout

      public void setDefaultTimeout(Duration timeout)
      Set the default timeout in 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 durations to use for the datagram socket connection.

    • setDefaultTimeout

      @Deprecated public void setDefaultTimeout(int timeout)
      Deprecated.
      Use setDefaultTimeout(Duration).
      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.

    • setSoTimeout

      public void setSoTimeout(Duration timeout) throws SocketException
      Set the timeout duration 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:
      SocketException - if an error setting the timeout.
      Since:
      3.10.0

    • setSoTimeout

      @Deprecated public void setSoTimeout(int timeout) throws SocketException
      Deprecated.
      Use setSoTimeout(Duration).
      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:
      SocketException - if an error setting the timeout.