src/kaka/cakelight/VideoDeviceListener.java

   1 package kaka.cakelight;
   2
   3 import java.io.File;
   4 import java.util.Optional;
   5 import java.util.function.Consumer;
   6
   7 import static kaka.cakelight.Main.log;
   8
   9 public class VideoDeviceListener {
  10     private Thread thread;
  11     private Consumer<Optional<File>> changeConsumer;
  12     private File lastDevice = null;
  13
  14     public void startListening() {
  15         thread = new Thread() {
  16             public void run() {
  17                 try {
  18                     while (!isInterrupted()) {
  19                         Optional<File> device = findVideoDevice();
  20                         if (!device.equals(Optional.ofNullable(lastDevice))) {
  21                             log("Video device change: %s", device.map(File::getAbsolutePath).orElse("none"));
  22                             changeConsumer.accept(device);
  23                             lastDevice = device.orElseGet(() -> null);
  24                         }
  25                         Thread.sleep(1000);
  26                     }
  27                 } catch (InterruptedException e) {
  28                 }
  29             }
  30         };
  31         thread.start();
  32     }
  33
  34     public void stopListening() {
  35         thread.interrupt();
  36     }
  37
  38     private Optional<File> findVideoDevice() {
  39         File[] files = new File("/dev").listFiles((dir, name) -> name.matches("video[0-9]+"));
  40         if (files == null || files.length == 0) {
  41             return Optional.empty();
  42         } else {
  43             return Optional.of(files[0]);
  44         }
  45     }
  46
  47     public void onVideoDeviceChange(Consumer<Optional<File>> consumer) {
  48         changeConsumer = consumer;
  49     }
  50 }