JSA (Java Socket API)

JSA is a packet-based communication system in Java

Don't use this, use packets4j instead

Summary

1. Introduction
2. Create a server
3. Create a client
4. Create a packet
5. Prepare a packet
6. Send a packet
7. Listeners
8. Create a custom packet

Introduction

This package includes a client/server solution to transfer series of key/values. Encryption is based on a symetric key for variable offset.

Each server/client has its own port which has been passed as an argument in the constructor, each port can only be used by one server/client. It's possible to add listeners to servers/clients, listeners contain methods (onPacketSended, onPacketReceived) which are called when a packet is sented or received by the server on which the listener is registered.

Create a server

Server side instantiation:

JSAServer server = new lu.poucy.jsa.server.JSAServer(3000, new int[] {1,2,3,4,5,6,7,8,9,0}).open();

Arguments of the server's constructor are:

1. The TCP-port on which the server has to listen,
2. The key to encrypt communications (array of minimum 4 numeric values)

Create a client

Client side instantiation:

JSAClient client = new lu.poucy.jsa.client.JSAClient(3001, new int[] {1,2,3,4,5,6,7,8,9,0}).open();

Arguments of the client's constructor are the same as the server. (Here...)

Create a packet

Packet instantiation:

Packet packet = new lu.poucy.jsa.packets.Packet(java.utils.Arrays.asList(
	new lu.poucy.jsa.utils.Pair<String, Object>("string", "value"),
	new lu.poucy.jsa.utils.Pair<String, Object>("int", 1),
	new lu.poucy.jsa.utils.Pair<String, Object>("double", 1.5),
	new lu.poucy.jsa.utils.Pair<String, Object>("object", new java.lang.Object())
));

or

java.utils.List<lu.poucy.jsa.utils.Pair<String, Object>> args = new java.utils.ArrayList<>();
args.add(new lu.poucy.jsa.utils.Pair<String, Object>("string", "value"));
args.add(new lu.poucy.jsa.utils.Pair<String, Object>("int", 1));
args.add(new lu.poucy.jsa.utils.Pair<String, Object>("double", 1.5));
args.add(new lu.poucy.jsa.utils.Pair<String, Object>("object", new java.lang.Object()));

Packet packet = new lu.poucy.jsa.packets.Packet(args);

A packet consists of a list of pairs of a text key and any kind of value. The value can be text, numeric and even an object.

Prepare a packet

Packet preparation:

PreparedPacket ppacket = new PreparedPacket(new Packet(new ArrayList()), InetAddress.getHost("localhost"), 3000);

A PreparedPacket is an intermediate step between creating the packet, and sending it. Arguments are:

1. The packet to be sent
2. The target ip-address
3. The target TCP-port

Send a packet

Packet transmission:

JSAServer server = new lu.poucy.jsa.server.JSAServer(3000, new char[] {1,2,3,4,5,6,7,8,9,0}).open();
JSAClient client = new lu.poucy.jsa.client.JSAClient(3001, new char[] {1,2,3,4,5,6,7,8,9,0}).open();

PreparedPacket ppacket = new PreparedPacket(new Packet(new ArrayList()), server.getHost(), server.getPort());

PacketSender sender = ppacket.send(client);

To send a packet, the PreparedPacket class contains a send function, the argument of which is the server/client with which it will be sent to the address that is passed as an argument in the constructor. This function returns a PacketSender which allows to start sending the packet, with the function start, the argument of this function is a functional interface, which will be called if an exception occurs. The send function in PreparedPacket automatically starts sending the packet. Each PacketSender can only be used once.

or

JSAServer server = new lu.poucy.jsa.server.JSAServer(3000, new char[] {1,2,3,4,5,6,7,8,9,0}).open();
JSAClient client = new lu.poucy.jsa.client.JSAClient(3001, new char[] {1,2,3,4,5,6,7,8,9,0}).open();

PreparedPacket ppacket = new PreparedPacket(new Packet(new ArrayList()), server.getHost(), server.getPort());

PacketSender sender = client.write(ppacket);
sender.start((exception) -> exception.printStackTrace());

The JSAServer or JSAClient classes contain a write function, the first and only argument is the PreparedPacket that will be sent. This function returns a PacketSender which allows to start sending the packet, with the function start, the argument of this function is a functional interface, which will be called if an exception occurs. Each PacketSender can only be used once.

Listeners

JSAListeners:

public class CustomListener implements lu.poucy.jsa.utils.JSAListener {
	public void onPacketReceived(Packet packet) {
		System.out.println("packet received: "+packet);
	}

	public void onPacketSended(Packet packet) {
		System.out.println("packet sended: "+packet);
	}
}

JSAListener serverListener = new CustomListener();
JSAListener clientListener = new CustomListener();

JSAServer server = new lu.poucy.jsa.server.JSAServer(3000, new char[] {1,2,3,4,5,6,7,8,9,0}).open();
JSAClient client = new lu.poucy.jsa.client.JSAClient(3001, new char[] {1,2,3,4,5,6,7,8,9,0}).open();

server.registerListener(serverListener);
client.registerListener(clientListener);

new PreparedPacket(new Packet(new ArrayList()), server.getHost(), server.getPort()).send(client);

server.unregisterListener(serverListener);
client.unregisterListener(clientListener);

It is possible to add listeners to the servers/clients, the functions registerListener and unregisterListener are used to register or unregister JSAListeners. The two function:

• onPacketReceived(Packet packet): This function is called when the serveror the client received a packet.
• onPacketSended(Packet packet): This function is called when the server or the client send a packet.

Create a custom packet

Create a custom packet:

Exemple

public class CarPacket extends lu.poucy.jsa.packets.Packet {
	public CarPacket(Car car) {
		super(new ArrayList<Pair<String, Object>>());
		addArg(new Pair<String, Object>("name", car.getName()));
		addArg(new Pair<String, Object>("wheelCount", car.getWheelCount()));
	}
	public static Car {
		private String name;
		private int wheelCount;
		public Car(String name, int wheelCount) {
			this.name = name;
			this.weelCount = weelCount;
		}
		public String getName() {return this.name;}
		public String getWheelCount() {return this.wheelCount;}
	}
}

public class CustomListener implements lu.poucy.jsa.utils.JSAListener {
	public void onPacketReceived(Packet packet) {
		System.out.println("packet received: "+packet);
	}

	public void onPacketSended(Packet packet) {
		System.out.println("packet sended: "+packet);
	}
}

JSAListener serverListener = new CustomListener();
JSAListener clientListener = new CustomListener();

JSAServer server = new lu.poucy.jsa.server.JSAServer(3000, new char[] {1,2,3,4,5,6,7,8,9,0}).open();
JSAClient client = new lu.poucy.jsa.client.JSAClient(3001, new char[] {1,2,3,4,5,6,7,8,9,0}).open();

server.registerListener(serverListener);
client.registerListener(clientListener);

new PreparedPacket(new CarPacket(new Car("Poucy's car", 4)), server.getHost(), server.getPort()).send(client);