1 /*
2 * Copyright © 2016 Greg Chabala
3 *
4 * This file is part of brick-control-lab.
5 *
6 * brick-control-lab is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as
8 * published by the Free Software Foundation, either version 3 of the
9 * License, or (at your option) any later version.
10 *
11 * brick-control-lab is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with brick-control-lab. If not, see http://www.gnu.org/licenses/.
18 */
19 package org.chabala.brick.controllab;
20
21 import org.slf4j.Logger;
22 import org.slf4j.LoggerFactory;
23
24 import java.util.Collections;
25 import java.util.HashSet;
26 import java.util.Set;
27
28 import static org.chabala.brick.controllab.Protocol.STOP_RELEASED;
29
30 /**
31 * Handle for stop button on a specific control lab instance. Obtain via {@link ControlLab#getStopButton()}.
32 */
33 public class StopButton {
34 private final Logger log = LoggerFactory.getLogger(getClass());
35 private final Set<StopButtonListener> stopButtonListeners;
36 private boolean stopDepressed = false;
37
38 StopButton(InputManager inputManager) {
39 stopButtonListeners = Collections.synchronizedSet(new HashSet<>(2));
40 inputManager.setStopButtonCallback(this::processStopButton);
41 }
42
43 /**
44 * Attach a listener for {@link StopButtonEvent}s.
45 *
46 * <p>Multiple listeners are allowed. A listener instance will only be registered
47 * once even if it is added multiple times.
48 * @param listener listener to add
49 */
50 public void addListener(StopButtonListener listener) {
51 stopButtonListeners.add(listener);
52 }
53
54 /**
55 * Remove a listener for {@link StopButtonEvent}s.
56 * @param listener listener to remove
57 */
58 public void removeListener(StopButtonListener listener) {
59 stopButtonListeners.remove(listener);
60 }
61
62 /**
63 * Returns current status of stop button.
64 * @return true if the stop button is in depressed state, false otherwise
65 */
66 public boolean isStopDepressed() {
67 return stopDepressed;
68 }
69
70 @SuppressWarnings("squid:S2629")
71 private void processStopButton(byte b) {
72 if (STOP_RELEASED != b) {
73 if (!stopDepressed) {
74 StopButtonEvent event = new StopButtonEvent(this, b);
75 log.info("Stop button depressed {}", String.format("0x%02X", b));
76 synchronized (stopButtonListeners) {
77 stopButtonListeners.forEach(l -> l.stopButtonPressed(event));
78 }
79 stopDepressed = true;
80 }
81 } else {
82 if (stopDepressed) {
83 StopButtonEvent event = new StopButtonEvent(this, b);
84 log.info("Stop button released {}", String.format("0x%02X", b));
85 synchronized (stopButtonListeners) {
86 stopButtonListeners.forEach(l -> l.stopButtonReleased(event));
87 }
88 stopDepressed = false;
89 }
90 }
91 }
92 }