Writer and scheduler for fixed-rate connections (untested).

components/net/sf/briar/transport/FrameScheduler.java

@@ -0,0 +1,36 @@
+package net.sf.briar.transport;
+
+import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
+
+/**
+ * A thread that calls the writeFullFrame() method of a PaddedConnectionWriter
+ * at regular intervals. The interval between calls is determined by a target
+ * output rate. If the underlying output stream cannot accept data at the
+ * target rate, calls will be made as frequently as the output stream allows.
+ */
+class FrameScheduler extends Thread {
+
+	private final PaddedConnectionWriter writer;
+	private final int millisPerFrame;
+
+	FrameScheduler(PaddedConnectionWriter writer, int bytesPerSecond) {
+		this.writer = writer;
+		millisPerFrame = bytesPerSecond * 1000 / MAX_FRAME_LENGTH;
+	}
+
+	@Override
+	public void run() {
+		long lastCall = System.currentTimeMillis();
+		while(true) {
+			long now = System.currentTimeMillis();
+			long nextCall = lastCall + millisPerFrame;
+			if(nextCall > now) {
+				try {
+					Thread.sleep(nextCall - now);
+				} catch(InterruptedException ignored) {}
+			}
+			lastCall = System.currentTimeMillis();
+			if(!writer.writeFullFrame()) return;
+		}
+	}
+}