/* * 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.io.IOException; import java.util.ArrayDeque; import java.util.Collection; import java.util.Deque; import javax.websocket.CloseReason; import javax.websocket.CloseReason.CloseCodes; import javax.websocket.Session; public class Snake { private static final int DEFAULT_LENGTH = 5; private final int id; private final Session session; private Direction direction; private int length = DEFAULT_LENGTH; private Location head; private final Deque<Location> tail = new ArrayDeque<>(); private final String hexColor; public Snake(int id, Session session) { this.id = id; this.session = session; this.hexColor = SnakeAnnotation.getRandomHexColor(); resetState(); } private void resetState() { this.direction = Direction.NONE; this.head = SnakeAnnotation.getRandomLocation(); this.tail.clear(); this.length = DEFAULT_LENGTH; } private synchronized void kill() { resetState(); sendMessage("{\"type\": \"dead\"}"); } private synchronized void reward() { length++; sendMessage("{\"type\": \"kill\"}"); } protected void sendMessage(String msg) { try { session.getBasicRemote().sendText(msg); } catch (IOException ioe) { CloseReason cr = new CloseReason(CloseCodes.CLOSED_ABNORMALLY, ioe.getMessage()); try { session.close(cr); } catch (IOException ioe2) { // Ignore } } } public synchronized void update(Collection<Snake> snakes) { Location nextLocation = head.getAdjacentLocation(direction); if (nextLocation.x >= SnakeAnnotation.PLAYFIELD_WIDTH) { nextLocation.x = 0; } if (nextLocation.y >= SnakeAnnotation.PLAYFIELD_HEIGHT) { nextLocation.y = 0; } if (nextLocation.x < 0) { nextLocation.x = SnakeAnnotation.PLAYFIELD_WIDTH; } if (nextLocation.y < 0) { nextLocation.y = SnakeAnnotation.PLAYFIELD_HEIGHT; } if (direction != Direction.NONE) { tail.addFirst(head); if (tail.size() > length) { tail.removeLast(); } head = nextLocation; } handleCollisions(snakes); } private void handleCollisions(Collection<Snake> snakes) { for (Snake snake : snakes) { boolean headCollision = id != snake.id && snake.getHead().equals(head); boolean tailCollision = snake.getTail().contains(head); if (headCollision || tailCollision) { kill(); if (id != snake.id) { snake.reward(); } } } } public synchronized Location getHead() { return head; } public synchronized Collection<Location> getTail() { return tail; } public synchronized void setDirection(Direction direction) { this.direction = direction; } public synchronized String getLocationsJson() { StringBuilder sb = new StringBuilder(); sb.append(String.format("{\"x\": %d, \"y\": %d}", Integer.valueOf(head.x), Integer.valueOf(head.y))); for (Location location : tail) { sb.append(','); sb.append(String.format("{\"x\": %d, \"y\": %d}", Integer.valueOf(location.x), Integer.valueOf(location.y))); } return String.format("{\"id\":%d,\"body\":[%s]}", Integer.valueOf(id), sb.toString()); } public int getId() { return id; } public String getHexColor() { return hexColor; } }