mstrengis / nonblocking

Easy to use nonblocking socket server and non blocking socket client.

NonBlocking

Easy to use nonblocking socket server and non blocking socket client. This example shows how to use server side when 1 socket command consists of 4bytes unsigned integer size of data string and the rest of it is a data string you can create your own protocol if you want.

Usage:

---

new Server(9510, new SocketListener(){
	  	private byte[] packetBuffer;
			private int DEFAULT_BUFFER_SIZE = 4, nextSize = DEFAULT_BUFFER_SIZE, packetBufferSize = 0, packetBufferLength = 0, needToRead = 0;
			@Override
			public void onData(Client client, ByteBuffer data, int bytesRead) {
				// f.e your command consists of unsigned integer as length of command and rest of the command is just a json string
	  			boolean error = false;
				byte[] buffer = null;
				if (!error) {
					buffer = new byte[bytesRead];
					data.get(buffer);
					
					if (packetBufferSize < packetBufferLength + bytesRead) {
						byte[] tmp = new byte[packetBufferLength + bytesRead];
						packetBufferSize = packetBufferLength + bytesRead;
						if (packetBufferLength > 0) {
							try {
								System.arraycopy(packetBuffer, 0, tmp, 0, packetBufferLength);
							} catch (Exception e) {
								e.printStackTrace();
								error = true;
							}
						}
						packetBuffer = tmp;
					}
				}
	
				if (packetBuffer == null) {
					error = true;
				}
	
				if (!error) {
					System.arraycopy(buffer, 0, packetBuffer, packetBufferLength, bytesRead);
					packetBufferLength += bytesRead;
				}
				
				if (!error) {
					try {
						while (packetBufferLength > 4) {
							long i1 = (int) (packetBuffer[0]) & 0xFF;
							long i2 = (int) (packetBuffer[1]) & 0xFF;
							long i3 = (int) (packetBuffer[2]) & 0xFF;
							long i4 = (int) (packetBuffer[3]) & 0xFF;
							needToRead = (int) ((i4 << 24) + (i3 << 16) + (i2 << 8) + i1) + 4;
							if (needToRead <= packetBufferLength && needToRead > 0 && packetBuffer != null) {
								byte[] work = new byte[needToRead];
								System.arraycopy(packetBuffer, 4, work, 0, needToRead - 4);
								String dataFromClient = new String(work, 0, needToRead - 4, "UTF-8");
								//use JSONObject notify connections save to db or whatever you want
								nextSize = DEFAULT_BUFFER_SIZE;
								if (!error) {
									if (packetBufferLength > 0) {
										packetBufferLength -= needToRead;
										System.arraycopy(packetBuffer, needToRead, packetBuffer, 0, packetBufferLength);
									}
								}
							} else {
								nextSize = needToRead - packetBufferLength;
								break;
							}
						}
					} catch (Exception e) {
						error = true;
							e.printStackTrace();
						}
					}
		
					if (error) {
						client.disconnect();
					}
				}
		
				@Override
				public void onDisconnect(Client client) {
				  // TODO notify other connecitons this client is disconnected and remove from your previously defined clients ArrayList
				}
		
				@Override
				public void onConnected(Client client) {
				  // TODO save your clients in some kind of ArrayList<Client> clients
				}
		});

---

Writing to clients:

		String queue = "{\"rq\":\"ping\"}"; //Just a sample use JSONObject().put("rq", "ping").toString() instead
		
		byte[] bytes = queue.getBytes();
		ByteBuffer buffer = ByteBuffer.allocate(bytes.length + 4); 
		int length = bytes.length; 
		
		//first four bytes is length of a command as unsigned integer
		buffer.put((byte) (length & 0xFF));
		buffer.put((byte) ((length >>> 8) & 0xFF));
		buffer.put((byte) ((length >>> 16) & 0xFF));
		buffer.put((byte) ((length >>> 24) & 0xFF));
		
		//rest of command is data
		buffer.put(bytes);
		
		buffer.flip(); //dont forget about flipping data before writing it to client

		client.write(buffer);