Added a device listener

[kaka/cakelight.git] / src / kaka / cakelight / VideoDeviceListener.java

diff --git a/src/kaka/cakelight/VideoDeviceListener.java b/src/kaka/cakelight/VideoDeviceListener.java
new file mode 100644 (file)
index 0000000..23c0b02
--- /dev/null
+++ b/src/kaka/cakelight/VideoDeviceListener.java
@@ -0,0 +1,50 @@
+package kaka.cakelight;
+
+import java.io.File;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import static kaka.cakelight.Main.log;
+
+public class VideoDeviceListener {
+    private Thread thread;
+    private Consumer<Optional<File>> changeConsumer;
+    private File lastDevice = null;
+
+    public void startListening() {
+       thread = new Thread() {
+           public void run() {
+               try {
+                   while (!isInterrupted()) {
+                       Optional<File> device = findVideoDevice();
+                       if (!device.equals(Optional.ofNullable(lastDevice))) {
+                           log("Video device change: %s", device.map(File::getAbsolutePath).orElse("none"));
+                           changeConsumer.accept(device);
+                           lastDevice = device.orElseGet(() -> null);
+                       }
+                       Thread.sleep(1000);
+                   }
+               } catch (InterruptedException e) {
+               }
+           }
+       };
+       thread.start();
+    }
+
+    public void stopListening() {
+        thread.interrupt();
+    }
+
+    private Optional<File> findVideoDevice() {
+       File[] files = new File("/dev").listFiles((dir, name) -> name.matches("video[0-9]+"));
+       if (files == null || files.length == 0) {
+           return Optional.empty();
+       } else {
+           return Optional.of(files[0]);
+       }
+    }
+
+    public void onVideoDeviceChange(Consumer<Optional<File>> consumer) {
+       changeConsumer = consumer;
+    }
+}