Package org.apache.commons.net.tftp

Class TFTP

java.lang.Object
org.apache.commons.net.DatagramSocketClient
org.apache.commons.net.tftp.TFTP
All Implemented Interfaces:
AutoCloseable
Direct Known Subclasses:
TFTPClient
public class TFTP extends DatagramSocketClient
The TFTP class exposes a set of methods to allow you to deal with the TFTP protocol directly, in case you want to write your own TFTP client or server. However, almost every user should only be concerend with the open() , and close() , methods. Additionally,the a setDefaultTimeout() method may be of importance for performance tuning.

Details regarding the TFTP protocol and the format of TFTP packets can be found in RFC 783. But the point of these classes is to keep you from having to worry about the internals.

See Also:

  • Field Details

  • Constructor Details

    • TFTP

      public TFTP()
      Creates a TFTP instance with a default timeout of DEFAULT_TIMEOUT_DURATION, a null socket, and buffered operations disabled.

  • Method Details

    • getModeName

      public static final String getModeName(int mode)
      Returns the TFTP string representation of a TFTP transfer mode. Will throw an ArrayIndexOutOfBoundsException if an invalid transfer mode is specified.
      Parameters:
      mode - The TFTP transfer mode. One of the MODE constants.
      Returns:
      The TFTP string representation of the TFTP transfer mode.

    • beginBufferedOps

      public final void beginBufferedOps()
      Initializes the internal buffers. Buffers are used by bufferedSend() and bufferedReceive() . This method must be called before calling either one of those two methods. When you finish using buffered operations, you must call endBufferedOps() .

    • bufferedReceive

      public final TFTPPacket bufferedReceive() throws IOException, InterruptedIOException, SocketException, TFTPPacketException
      This is a special method to perform a more efficient packet receive. It should only be used after calling beginBufferedOps() . beginBufferedOps() initializes a set of buffers used internally that prevent the new allocation of a DatagramPacket and byte array for each send and receive. To use these buffers you must call the bufferedReceive() and bufferedSend() methods instead of send() and receive(). You must also be certain that you don't manipulate the resulting packet in such a way that it interferes with future buffered operations. For example, a TFTPDataPacket received with bufferedReceive() will have a reference to the internal byte buffer. You must finish using this data before calling bufferedReceive() again, or else the data will be overwritten by the call.
      Returns:
      The TFTPPacket received.
      Throws:
      InterruptedIOException - If a socket timeout occurs. The Java documentation claims an InterruptedIOException is thrown on a DatagramSocket timeout, but in practice we find a SocketException is thrown. You should catch both to be safe.
      SocketException - If a socket timeout occurs. The Java documentation claims an InterruptedIOException is thrown on a DatagramSocket timeout, but in practice we find a SocketException is thrown. You should catch both to be safe.
      IOException - If some other I/O error occurs.
      TFTPPacketException - If an invalid TFTP packet is received.

    • bufferedSend

      public final void bufferedSend(TFTPPacket packet) throws IOException
      This is a special method to perform a more efficient packet send. It should only be used after calling beginBufferedOps() . beginBufferedOps() initializes a set of buffers used internally that prevent the new allocation of a DatagramPacket and byte array for each send and receive. To use these buffers you must call the bufferedReceive() and bufferedSend() methods instead of send() and receive(). You must also be certain that you don't manipulate the resulting packet in such a way that it interferes with future buffered operations. For example, a TFTPDataPacket received with bufferedReceive() will have a reference to the internal byte buffer. You must finish using this data before calling bufferedReceive() again, or else the data will be overwritten by the call.
      Parameters:
      packet - The TFTP packet to send.
      Throws:
      IOException - If some I/O error occurs.

    • discardPackets

      public final void discardPackets() throws IOException
      This method synchronizes a connection by discarding all packets that may be in the local socket buffer. This method need only be called when you implement your own TFTP client or server.
      Throws:
      IOException - if an I/O error occurs.

    • endBufferedOps

      public final void endBufferedOps()
      Releases the resources used to perform buffered sends and receives.

    • receive

      public final TFTPPacket receive() throws IOException, InterruptedIOException, SocketException, TFTPPacketException
      Receives a TFTPPacket.
      Returns:
      The TFTPPacket received.
      Throws:
      InterruptedIOException - If a socket timeout occurs. The Java documentation claims an InterruptedIOException is thrown on a DatagramSocket timeout, but in practice we find a SocketException is thrown. You should catch both to be safe.
      SocketException - If a socket timeout occurs. The Java documentation claims an InterruptedIOException is thrown on a DatagramSocket timeout, but in practice we find a SocketException is thrown. You should catch both to be safe.
      IOException - If some other I/O error occurs.
      TFTPPacketException - If an invalid TFTP packet is received.

    • send

      public final void send(TFTPPacket packet) throws IOException
      Sends a TFTP packet to its destination.
      Parameters:
      packet - The TFTP packet to send.
      Throws:
      IOException - If some I/O error occurs.

    • trace

      protected void trace(String direction, TFTPPacket packet)
      Trace facility; this implementation does nothing.

      Override it to trace the data, for example:
      System.out.println(direction + " " + packet.toString());

      Parameters:
      direction - > or <
      packet - the packet to be sent or that has been received respectively
      Since:
      3.6