public final class DatagramPacket extends Object
Datagram packets are used to implement a connectionless packet delivery service. Each message is routed from one machine to another based solely on information contained within that packet. Multiple packets sent from one machine to another might be routed differently, and might arrive in any order. Packet delivery is not guaranteed.
Unless otherwise specified, passing a null
argument causes
a NullPointerException
to be thrown.
Methods and constructors of DatagramPacket
accept parameters
of type SocketAddress
. DatagramPacket
supports
InetSocketAddress
, and may support additional SocketAddress
sub-types.
- Since:
- 1.0
-
Constructor Summary
Constructors Constructor Description DatagramPacket(byte[] buf, int length)
Constructs aDatagramPacket
for receiving packets of lengthlength
.DatagramPacket(byte[] buf, int offset, int length)
Constructs aDatagramPacket
for receiving packets of lengthlength
, specifying an offset into the buffer.DatagramPacket(byte[] buf, int offset, int length, InetAddress address, int port)
Constructs a datagram packet for sending packets of lengthlength
with offsetoffset
to the specified port number on the specified host.DatagramPacket(byte[] buf, int offset, int length, SocketAddress address)
Constructs a datagram packet for sending packets of lengthlength
with offsetoffset
to the specified port number on the specified host.DatagramPacket(byte[] buf, int length, InetAddress address, int port)
Constructs a datagram packet for sending packets of lengthlength
to the specified port number on the specified host.DatagramPacket(byte[] buf, int length, SocketAddress address)
Constructs a datagram packet for sending packets of lengthlength
to the specified port number on the specified host. -
Method Summary
Modifier and Type Method Description InetAddress
getAddress()
Returns the IP address of the machine to which this datagram is being sent or from which the datagram was received, ornull
if not set.byte[]
getData()
Returns the data buffer.int
getLength()
Returns the length of the data to be sent or the length of the data received.int
getOffset()
Returns the offset of the data to be sent or the offset of the data received.int
getPort()
Returns the port number on the remote host to which this datagram is being sent or from which the datagram was received, or 0 if not set.SocketAddress
getSocketAddress()
Returns theSocketAddress
(usually IP address + port number) of the remote host that this packet is being sent to or is coming from.void
setAddress(InetAddress iaddr)
Sets the IP address of the machine to which this datagram is being sent.void
setData(byte[] buf)
Set the data buffer for this packet.void
setData(byte[] buf, int offset, int length)
Set the data buffer for this packet.void
setLength(int length)
Set the length for this packet.void
setPort(int iport)
Sets the port number on the remote host to which this datagram is being sent.void
setSocketAddress(SocketAddress address)
Sets the SocketAddress (usually IP address + port number) of the remote host to which this datagram is being sent.
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Constructor Details
-
DatagramPacket
public DatagramPacket(byte[] buf, int offset, int length)Constructs aDatagramPacket
for receiving packets of lengthlength
, specifying an offset into the buffer.The
length
argument must be less than or equal tobuf.length
.- Parameters:
buf
- buffer for holding the incoming datagram.offset
- the offset for the bufferlength
- the number of bytes to read.- Throws:
IllegalArgumentException
- if the length or offset is negative, or if the length plus the offset is greater than the length of the packet's given buffer.- Since:
- 1.2
-
DatagramPacket
public DatagramPacket(byte[] buf, int length)Constructs aDatagramPacket
for receiving packets of lengthlength
.The
length
argument must be less than or equal tobuf.length
.- Parameters:
buf
- buffer for holding the incoming datagram.length
- the number of bytes to read.- Throws:
IllegalArgumentException
- if the length is negative or if the length is greater than the length of the packet's given buffer.
-
DatagramPacket
Constructs a datagram packet for sending packets of lengthlength
with offsetoffset
to the specified port number on the specified host. Thelength
argument must be less than or equal tobuf.length
.- Parameters:
buf
- the packet data.offset
- the packet data offset.length
- the packet data length.address
- the destination address, ornull
.port
- the destination port number.- Throws:
IllegalArgumentException
- if the length or offset is negative, or if the length plus the offset is greater than the length of the packet's given buffer, or if the port is out of range.- Since:
- 1.2
- See Also:
InetAddress
-
DatagramPacket
Constructs a datagram packet for sending packets of lengthlength
with offsetoffset
to the specified port number on the specified host. Thelength
argument must be less than or equal tobuf.length
.- Parameters:
buf
- the packet data.offset
- the packet data offset.length
- the packet data length.address
- the destination socket address.- Throws:
IllegalArgumentException
- if address is null or its type is not supported, or if the length or offset is negative, or if the length plus the offset is greater than the length of the packet's given buffer.- Since:
- 1.4
- See Also:
InetAddress
-
DatagramPacket
Constructs a datagram packet for sending packets of lengthlength
to the specified port number on the specified host. Thelength
argument must be less than or equal tobuf.length
.- Parameters:
buf
- the packet data.length
- the packet length.address
- the destination address, ornull
.port
- the destination port number.- Throws:
IllegalArgumentException
- if the length is negative, or if the length is greater than the length of the packet's given buffer, or if the port is out of range.- See Also:
InetAddress
-
DatagramPacket
Constructs a datagram packet for sending packets of lengthlength
to the specified port number on the specified host. Thelength
argument must be less than or equal tobuf.length
.- Parameters:
buf
- the packet data.length
- the packet length.address
- the destination address.- Throws:
IllegalArgumentException
- if address is null or its type is not supported, or if the length is negative, or if the length is greater than the length of the packet's given buffer, or if the port is out of range.- Since:
- 1.4
- See Also:
InetAddress
-
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Method Details
-
getAddress
Returns the IP address of the machine to which this datagram is being sent or from which the datagram was received, ornull
if not set.- Returns:
- the IP address of the machine to which this datagram is being sent or from which the datagram was received.
- See Also:
InetAddress
,setAddress(java.net.InetAddress)
-
getPort
public int getPort()Returns the port number on the remote host to which this datagram is being sent or from which the datagram was received, or 0 if not set.- Returns:
- the port number on the remote host to which this datagram is being sent or from which the datagram was received.
- See Also:
setPort(int)
-
getData
public byte[] getData()Returns the data buffer. The data received or the data to be sent starts from theoffset
in the buffer, and runs forlength
long.- Returns:
- the buffer used to receive or send data
- See Also:
setData(byte[], int, int)
-
getOffset
public int getOffset()Returns the offset of the data to be sent or the offset of the data received.- Returns:
- the offset of the data to be sent or the offset of the data received.
- Since:
- 1.2
-
getLength
public int getLength()Returns the length of the data to be sent or the length of the data received.- Returns:
- the length of the data to be sent or the length of the data received.
- See Also:
setLength(int)
-
setData
public void setData(byte[] buf, int offset, int length)Set the data buffer for this packet. This sets the data, length and offset of the packet.- Parameters:
buf
- the buffer to set for this packetoffset
- the offset into the datalength
- the length of the data and/or the length of the buffer used to receive data- Throws:
IllegalArgumentException
- if the length or offset is negative, or if the length plus the offset is greater than the length of the packet's given buffer.- Since:
- 1.2
- See Also:
getData()
,getOffset()
,getLength()
-
setAddress
Sets the IP address of the machine to which this datagram is being sent.- Parameters:
iaddr
- theInetAddress
, ornull
.- Since:
- 1.1
- See Also:
getAddress()
-
setPort
public void setPort(int iport)Sets the port number on the remote host to which this datagram is being sent.- Parameters:
iport
- the port number- Throws:
IllegalArgumentException
- if the port is out of range- Since:
- 1.1
- See Also:
getPort()
-
setSocketAddress
Sets the SocketAddress (usually IP address + port number) of the remote host to which this datagram is being sent.- Parameters:
address
- theSocketAddress
- Throws:
IllegalArgumentException
- if address is null or is a SocketAddress subclass not supported.- Since:
- 1.4
- See Also:
getSocketAddress()
-
getSocketAddress
Returns theSocketAddress
(usually IP address + port number) of the remote host that this packet is being sent to or is coming from.- Returns:
- the
SocketAddress
- Since:
- 1.4
- See Also:
setSocketAddress(java.net.SocketAddress)
-
setData
public void setData(byte[] buf)Set the data buffer for this packet. With the offset of this DatagramPacket set to 0, and the length set to the length ofbuf
.- Parameters:
buf
- the buffer to set for this packet.- Since:
- 1.1
- See Also:
getLength()
,getData()
-
setLength
public void setLength(int length)Set the length for this packet. The length of the packet is the number of bytes from the packet's data buffer that will be sent, or the number of bytes of the packet's data buffer that will be used for receiving data. The length must be lesser or equal to the offset plus the length of the packet's buffer.- Parameters:
length
- the length to set for this packet.- Throws:
IllegalArgumentException
- if the length is negative, or if the length plus the offset is greater than the length of the packet's data buffer.- Since:
- 1.1
- See Also:
getLength()
,setData(byte[], int, int)
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