Generic Connection Framework (GCF) by R4R Team

HttpConnection conn =

(HttpConnection) Connector.open("http://http://www.r4r.co.in/");

conn.setRequestMethod(HttpConnection.GET);

DataInputStream din = conn.openDataInputStream();

ByteArrayOutputStream bos = new ByteArrayOutputStream();

byte[] buf = new byte[256];

while (true) {

int rd = din.read(buf, 0, 256);

if (rd == -1) break;

bos.write(buf, 0, rd);

}

bos.flush();

buf = bos.toByteArray();

// Convert the byte array to string using the
// character encoding format of the remote site
String content = new String (buf, "UTF-8");


HttpsConnection:

The HttpsConnection object represents a secure HTTP (HTTPS) connection. HTTPS support is mandated in MIDP 2.0 . It supports both user authentication and data encryption. The URL scheme for HttpsConnection is https://. Ex:


HttpsConnection hsc =
(HttpsConnection) Connector.open("https:"/www.r4r.co.in);
The HTTPS protocol utilizes the public key infrastructure to authenticate communication parties and ensure data confidentiality once the connection is established. Digital certificates are used for authentication, and public key algorithms are used to exchange the information

SocketConnection A socket connection allows the client to communicate to specific socket ports. The URL string of SocketConnection objects takes the format of socket://host:port. The important methods in the SocketConnection interface are (i) openDataInputStream() and (ii) openDataOutputStream(), which open data streams for the client to communicate with the remote socket.

We can also specify the operation mode of the SocketConnection using the setSocketOption() method. void setSocketOption (byte option, int value) int getSocketOption (byte option

SecureConnection A SecureConnection interface extends the SocketConnection interface to add support for the Secure Socket Layer (SSL). Its URL string takes the form ssl://host:port

ServerSocketConnection The ServerSocketConnection allows us to listen for incoming connections on a socket port and essentially turns the device into a server this is not available in MIDP 1.0. Its URL string has the format of socket://:port, where the port parameter is the port number to listen to. An external device can now connect to the server device using the socket://host:port connection string, where host is the IP address of the server device. Once a ServerSocketConnection object is instantiated, we can call the acceptAndOpen() method in a loop to listen for incoming connections.

// Create the server listening socket for port 57

ServerSocketConnection scn =

(ServerSocketConnection) Connector.open("socket://:57");

while (true) {

SocketConnection sc =

(SocketConnection) scn.acceptAndOpen();

sc.setSocketOption(RCVBUF, 128);

sc.setSocketOption(SNDBUF, 128);

sc.close ();

}

scn.close ();

CommConnection This supports access to the device's serial port or logical serial port (e.g., the IrDA port). The URL scheme takes the form comm:port_id;params. The port_id is COM# for RS232 serial ports and IR# for IrDA ports. For example, the URL string comm:IR0;baudrate=19200 opens a connection to the first infrared port with a 19,200 bit per second data rate.


UDPDatagramConnection The datagram protocol directly passes data packets between endpoints without trying to assemble them to match their originating order or recover lost data. The datagram arrival order or even the delivery itself is not guaranteed. It is, however, often faster and more suitable for real-time applications.

The UDPDatagramConnection interface inherits from the DatagramConnection interface. The URL string is datagram://host:port. It cannot open data streams but has methods to support composing, sending, and receiving datagrams.

Datagram newDatagram(int i)

Datagram newDatagram(int i, String s)

Datagram newDatagram(byte[] bytes, int i)

Datagram newDatagram(byte[] bytes, int i, String s)

void send(Datagram datagram)

void receive(Datagram datagram)

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