File	Doc	Category	Size	Date	Package
UDPClient.java	API Doc	Example	4918	Sat Sep 09 20:51:30 BST 2000	None

UDPClient

• java.lang.Object

Fields Summary
private InetAddress	remote
private int	port
private DatagramSocket	ds
private byte[]	receiveBuffer

Constructors Summary
public UDPClient(InetAddress remoteHost, int remotePort, int timeout) Creates a new UDPClient. param remoteHost The address of the remote host to which data will be sent param port The port on the remote host to which data will be sent param timeout The number of milliseconds to wait to receive a packet before timing out throws SocketException this.remote = remoteHost; this.port = remotePort; ds = new DatagramSocket(); // the next lines require Java 2 ds.connect(remote, port); ds.setSoTimeout(timeout);
public UDPClient(InetAddress remoteHost, int remotePort) this.remote = remoteHost; this.port = remotePort; ds = new DatagramSocket(); // the next line requires Java 2 ds.connect(remote, port);
public UDPClient(String hostname, int port) this(InetAddress.getByName(hostname), port);

Methods Summary
public java.net.InetAddress	getAddress() return the InetAddress which this client sends data to return this.remote;
public int	getLocalPort() return the port which this client is bound to return this.ds.getLocalPort();
public int	getPort() return the port which this object sends data to return this.port;
public static void	main(java.lang.String[] args) String hostname = "localhost"; int port = 7; if (args.length > 0) { hostname = args[0]; } if (args.length > 1) { try { port = Integer.parseInt(args[1]); } catch (Exception e) {} } try { InetAddress ia = InetAddress.getByName(hostname); UDPClient client = new UDPClient(ia, port); Random r = new Random(); for (int i = 1; i <= 8192; i++) { try { byte[] data = new byte[i]; r.nextBytes(data); client.send(data); byte[] result = client.receive(); if (result.length != data.length) { System.err.println("Packet " + i + " failed; input length: " + data.length + "; output length: " + result.length); continue; } for (int j = 0; j < result.length; j++) { if (data[j] != result[j]) { System.err.println("Packet " + i + " failed; data mismatch"); break; } } } catch (IOException e) { System.err.println("Packet " + i + " failed with " + e); } } } catch (UnknownHostException e) { System.err.println(e); } catch (SocketException se) { System.err.println(se); }
public byte[]	receive() This method blocks until a UDP Datagram is received. This can be an indefinite amount of time if the host is unreachable so calls to this method should be placed in a separate thread from the main program. return the data received as a byte array throws IOException DatagramPacket incoming = new DatagramPacket(receiveBuffer, receiveBuffer.length); ds.receive(incoming); byte[] result = new byte[incoming.getLength()]; System.arraycopy(incoming.getData(), 0, result, 0, incoming.getLength()); return result;
public void	send(byte[] data) This method sends data to the remote host via UDP. If the array is longer than the maximum reliable length of a UDP Datagram (8192) bytes then an IOException is thrown param data A byte array containing the data to be sent throws IOException if (data.length > 8192) throw new IOException("Too much data"); DatagramPacket dp = new DatagramPacket(data, data.length, remote, port); ds.send(dp);
public void	send() This method sends an empty datagram to the remote host via UDP. throws IOException byte[] b = new byte[1]; this.send(b);
public java.lang.String	toString() return a String showing the remote host and port which this client sends data to return "[UDPClient:address=" + remote + ";port=" + port + "]";