Package org.apache.commons.net.tftp
Class TFTPPacket
java.lang.Object
org.apache.commons.net.tftp.TFTPPacket
- Direct Known Subclasses:
TFTPAckPacket
,TFTPDataPacket
,TFTPErrorPacket
,TFTPRequestPacket
TFTPPacket is an abstract class encapsulating the functionality common to the 5 types of TFTP packets. It also provides a static factory method that will
create the correct TFTP packet instance from a datagram. This relieves the programmer from having to figure out what kind of TFTP packet is contained in a
datagram and create it himself.
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. Additionally, only very few people should have to care about any of the TFTPPacket classes or derived classes. Almost all users
should only be concerned with the TFTPClient
class receiveFile()
and sendFile()
methods.
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
This is the actual TFTP spec identifier and is equal to 4.(package private) InetAddress
The host the packet is going to be sent or where it came from.static final int
This is the actual TFTP spec identifier and is equal to 3.static final int
This is the actual TFTP spec identifier and is equal to 5.(package private) static final int
The minimum size of a packet.(package private) int
The port the packet came from or is going to.static final int
This is the actual TFTP spec identifier and is equal to 1.static final int
The TFTP data packet maximum segment size in bytes.(package private) int
The type of packet.static final int
This is the actual TFTP spec identifier and is equal to 2. -
Constructor Summary
ConstructorsConstructorDescriptionTFTPPacket
(int type, InetAddress address, int port) This constructor is not visible outside the package. -
Method Summary
Modifier and TypeMethodDescriptionfinal InetAddress
Returns the address of the host where the packet is going to be sent or where it came from.final int
getPort()
Returns the port where the packet is going to be sent or where it came from.final int
getType()
Returns the type of the packet.abstract DatagramPacket
Creates a UDP datagram containing all the TFTP packet data in the proper format.(package private) abstract DatagramPacket
newDatagram
(DatagramPacket datagram, byte[] data) This is an abstract method only available within the package for implementing efficient datagram transport by eliminating buffering.static final TFTPPacket
newTFTPPacket
(DatagramPacket datagram) When you receive a datagram that you expect to be a TFTP packet, you use this factory method to create the proper TFTPPacket object encapsulating the data contained in that datagram.final void
setAddress
(InetAddress address) Sets the host address where the packet is going to be sent.final void
setPort
(int port) Sets the port where the packet is going to be sent.toString()
For debugging
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Field Details
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MIN_PACKET_SIZE
static final int MIN_PACKET_SIZEThe minimum size of a packet. This is 4 bytes. It is enough to store the opcode and blocknumber or other required data depending on the packet type.- See Also:
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READ_REQUEST
public static final int READ_REQUESTThis is the actual TFTP spec identifier and is equal to 1. Identifier returned bygetType()
indicating a read request packet.- See Also:
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WRITE_REQUEST
public static final int WRITE_REQUESTThis is the actual TFTP spec identifier and is equal to 2. Identifier returned bygetType()
indicating a write request packet.- See Also:
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DATA
public static final int DATAThis is the actual TFTP spec identifier and is equal to 3. Identifier returned bygetType()
indicating a data packet.- See Also:
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ACKNOWLEDGEMENT
public static final int ACKNOWLEDGEMENTThis is the actual TFTP spec identifier and is equal to 4. Identifier returned bygetType()
indicating an acknowledgement packet.- See Also:
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ERROR
public static final int ERRORThis is the actual TFTP spec identifier and is equal to 5. Identifier returned bygetType()
indicating an error packet.- See Also:
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SEGMENT_SIZE
public static final int SEGMENT_SIZEThe TFTP data packet maximum segment size in bytes. This is 512 and is useful for those familiar with the TFTP protocol who want to use theTFTP
class methods to implement their own TFTP servers or clients.- See Also:
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type
int typeThe type of packet. -
port
int portThe port the packet came from or is going to. -
address
InetAddress addressThe host the packet is going to be sent or where it came from.
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Constructor Details
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TFTPPacket
TFTPPacket(int type, InetAddress address, int port) This constructor is not visible outside the package. It is used by subclasses within the package to initialize base data.- Parameters:
type
- The type of the packet.address
- The host the packet came from or is going to be sent.port
- The port the packet came from or is going to be sent.
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Method Details
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newTFTPPacket
When you receive a datagram that you expect to be a TFTP packet, you use this factory method to create the proper TFTPPacket object encapsulating the data contained in that datagram. This method is the only way you can instantiate a TFTPPacket derived class from a datagram.- Parameters:
datagram
- The datagram containing a TFTP packet.- Returns:
- The TFTPPacket object corresponding to the datagram.
- Throws:
TFTPPacketException
- If the datagram does not contain a valid TFTP packet.
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getAddress
Returns the address of the host where the packet is going to be sent or where it came from.- Returns:
- The type of the packet.
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getPort
public final int getPort()Returns the port where the packet is going to be sent or where it came from.- Returns:
- The port where the packet came from or where it is going.
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getType
public final int getType()Returns the type of the packet.- Returns:
- The type of the packet.
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newDatagram
Creates a UDP datagram containing all the TFTP packet data in the proper format. This is an abstract method, exposed to the programmer in case he wants to implement his own TFTP client instead of using theTFTPClient
class. Under normal circumstances, you should not have a need to call this method.- Returns:
- A UDP datagram containing the TFTP packet.
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newDatagram
This is an abstract method only available within the package for implementing efficient datagram transport by eliminating buffering. It takes a datagram as an argument, and a byte buffer in which to store the raw datagram data. Inside the method, the data should be set as the datagram's data and the datagram returned.- Parameters:
datagram
- The datagram to create.data
- The buffer to store the packet and to use in the datagram.- Returns:
- The datagram argument.
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setAddress
Sets the host address where the packet is going to be sent.- Parameters:
address
- the address to set
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setPort
public final void setPort(int port) Sets the port where the packet is going to be sent.- Parameters:
port
- the port to set
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toString
For debugging
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