add java support (OMG WHY!?!)

.gitignore

@@ -6,6 +6,7 @@ venv/
 __pycache__/
 *.py[cod]
 *$py.class
+*.class
 
 # C extensions
 *.so

README.md

@@ -94,6 +94,7 @@ First, copy example code to main dir with game. Example codes are for:
 * [python](battle_city/examples/python/radom.py)
 * [nodejs](battle_city/examples/nodejs/random.js)
 * [ruby](battle_city/examples/ruby/random.rb)
+* [java](battle_city/examples/java/Game.java)
 
 (more examples are [here](battle_city/examples/))
 
@@ -102,15 +103,34 @@ remember about virtualenv or pipenv!
 * https://docs.python.org/3/tutorial/venv.html
 * https://pipenv.readthedocs.io/en/latest/
 
-#### For linux/mingw/osx/wsl
+### For linux/mingw/osx/wsl
+
+#### Python
+```sh
+./run_game.sh --cmd-p1 "python copied_client.py"
+```
+
+#### NodeJs
+```sh
+./run_game.sh --cmd-p1 "nodejs copied_client.js"
+```
+
+#### Ruby
+```sh
+./run_game.sh --cmd-p1 "ruby copied_client.rb"
+```
+
+#### Java
+oh my god, what a terrible language! You need a json-simple package
 ```sh
-./run_game.sh --cmd-p1 "python|nodejs|ruby copied_client.prefix"
+javac -cp /usr/share/java/json-simple.jar Game.java -d .
+./run_game.sh --cmd-p1 "java -cp /usr/share/java/json-simple.jar:. Game"
 ```
 
  The color of your tank will be yellow.
 
 
-#### maybe windows?
+### maybe windows?
 Omg why?
 
 You have four options:
@@ -123,7 +143,7 @@ You have four options:
     * `python client_a.py`
     * `python -m battle_city.examples.random`
 
-#### tmux version - more hackerable (with split screens in terminal)!
+### tmux version - more hackerable (with split screens in terminal)!
 ```
 ./run_game_tmux.sh --cmd-p1 "python copied_client.py"
 ```

battle_city/examples/java/Game.java

@@ -0,0 +1,79 @@
+import java.io.*;
+import java.net.Socket;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+public class Game {
+    private OutputStream writer;
+    private boolean start;
+    private boolean firstTick;
+    private long timestamp;
+
+    private Game(Socket socket) throws IOException {
+        start = false;
+        firstTick = false;
+        timestamp = 0;
+
+        writer = socket.getOutputStream();
+    }
+
+    public void receive(JSONObject data) {
+        // java with not external libs doesnt have async code
+        // so I must check timestamp and run tick
+        long newTimestamp = System.currentTimeMillis();
+        if (timestamp - newTimestamp > 250) {
+            timestamp = newTimestamp;
+            tick();
+        }
+
+        System.out.println(data.toJSONString());
+    }
+
+    public void tick() {
+        if (!firstTick) {
+            JSONObject obj = new JSONObject();
+            obj.put("action", "greet");
+            obj.put("name", "JAVA");
+            send(obj);
+            firstTick = true;
+        }
+        if (start) {
+            // do sth
+        }
+    }
+
+    public void send(JSONObject obj) {
+        try {
+            writer.write(obj.toJSONString().getBytes());
+            writer.write('\n');
+            writer.flush();
+        } catch (IOException e) {}
+    }
+
+    public static void main(String[] args) throws IOException {
+        Socket socket = new Socket("127.0.0.1", 8888);
+        try {
+            Game game = new Game(socket);
+            BufferedReader reader = new BufferedReader(
+                new InputStreamReader(socket.getInputStream())
+            );
+            System.out.println("\033[1mCONNECTED!\033[0m");
+
+            game.tick();
+
+            JSONParser parser = new JSONParser();
+            String line;
+            while((line = reader.readLine()) != null) {
+                try {
+                    JSONObject obj = (JSONObject) parser.parse(line);
+                    game.receive(obj);
+                } catch (ParseException e) {}
+            }
+        } catch (IOException e) {
+            throw e;
+        } finally {
+            socket.close();
+        }
+    }
+}