/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package websocket.snake;
import java.awt.Color;
import java.io.IOException;
import java.util.Iterator;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import jakarta.websocket.OnClose;
import jakarta.websocket.OnError;
import jakarta.websocket.OnMessage;
import jakarta.websocket.OnOpen;
import jakarta.websocket.Session;
import jakarta.websocket.server.ServerEndpoint;
@ServerEndpoint(value = "/websocket/snake")
public class SnakeAnnotation {
public static final int PLAYFIELD_WIDTH = 640;
public static final int PLAYFIELD_HEIGHT = 480;
public static final int GRID_SIZE = 10;
private static final AtomicInteger snakeIds = new AtomicInteger(0);
private static final Random random = new Random();
private final int id;
private Snake snake;
public static String getRandomHexColor() {
float hue = random.nextFloat();
// sat between 0.1 and 0.3
float saturation = (random.nextInt(2000) + 1000) / 10000f;
float luminance = 0.9f;
Color color = Color.getHSBColor(hue, saturation, luminance);
return '#' + Integer.toHexString(
(color.getRGB() & 0xffffff) | 0x1000000).substring(1);
}
public static Location getRandomLocation() {
int x = roundByGridSize(random.nextInt(PLAYFIELD_WIDTH));
int y = roundByGridSize(random.nextInt(PLAYFIELD_HEIGHT));
return new Location(x, y);
}
private static int roundByGridSize(int value) {
value = value + (GRID_SIZE / 2);
value = value / GRID_SIZE;
value = value * GRID_SIZE;
return value;
}
public SnakeAnnotation() {
this.id = snakeIds.getAndIncrement();
}
@OnOpen
public void onOpen(Session session) {
// If the messages take longer than TICK_DELAY to be sent, the game isn't going to work properly.
session.getUserProperties().put("org.apache.tomcat.websocket.BLOCKING_SEND_TIMEOUT",
Long.valueOf(SnakeTimer.TICK_DELAY));
this.snake = new Snake(id, session);
SnakeTimer.addSnake(snake);
StringBuilder sb = new StringBuilder();
for (Iterator<Snake> iterator = SnakeTimer.getSnakes().iterator();
iterator.hasNext();) {
Snake snake = iterator.next();
sb.append(String.format("{\"id\": %d, \"color\": \"%s\"}",
Integer.valueOf(snake.getId()), snake.getHexColor()));
if (iterator.hasNext()) {
sb.append(',');
}
}
SnakeTimer.broadcast(String.format("{\"type\": \"join\",\"data\":[%s]}", sb.toString()));
}
@OnMessage
public void onTextMessage(String message) {
if ("west".equals(message)) {
snake.setDirection(Direction.WEST);
} else if ("north".equals(message)) {
snake.setDirection(Direction.NORTH);
} else if ("east".equals(message)) {
snake.setDirection(Direction.EAST);
} else if ("south".equals(message)) {
snake.setDirection(Direction.SOUTH);
}
}
@OnClose
public void onClose() {
SnakeTimer.removeSnake(snake);
SnakeTimer.broadcast(String.format("{\"type\": \"leave\", \"id\": %d}", Integer.valueOf(id)));
}
@OnError
public void onError(Throwable t, Session session) throws Throwable {
/*
* Assume all errors are fatal. Close the session and remove the snake from the game.
*/
session.close();
/*
* Correct action depends on root cause. Protect against infinite loops while looking for root cause.
*/
int count = 0;
Throwable root = t;
while (root.getCause() != null && count < 20) {
root = root.getCause();
count ++;
}
if (root instanceof IOException) {
/*
* User going away can present in different ways depending on their platform and exactly what went wrong.
* Assume that any IO issue is some form of the user going away and ignore it.
*/
} else {
throw t;
}
}
}