Reduced CPU usage in MidiInputDevice.

kshoji · Mar 24, 2014 · 3cfa61d · 3cfa61d
1 parent a0b0626
commit 3cfa61d
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Showing 2 changed files with 23 additions and 8 deletions.
diff --git a/MIDIDriver/src/jp/kshoji/driver/midi/device/MidiInputDevice.java b/MIDIDriver/src/jp/kshoji/driver/midi/device/MidiInputDevice.java
@@ -59,7 +59,7 @@ public MidiInputDevice(UsbDevice usbDevice, UsbDeviceConnection usbDeviceConnect
 	public void stop() {
 		usbDeviceConnection.releaseInterface(usbInterface);
 
-		waiterThread.suspendFlag = false;
+		resume();
 		waiterThread.stopFlag = true;
 
 		// blocks while the thread will stop
@@ -76,14 +76,19 @@ public void stop() {
 	 * Suspends event listening
 	 */
 	public void suspend() {
-		waiterThread.suspendFlag = true;
+		synchronized (waiterThread.suspendSignal) {
+			waiterThread.suspendFlag = true;
+		}
 	}
 
 	/**
 	 * Resumes event listening
 	 */
 	public void resume() {
-		waiterThread.suspendFlag = false;
+		synchronized (waiterThread.suspendSignal) {
+			waiterThread.suspendFlag = false;
+			waiterThread.suspendSignal.notifyAll();
+		}
 	}
 
 	/**
@@ -115,6 +120,7 @@ public UsbEndpoint getUsbEndpoint() {
 	 */
 	final class WaiterThread extends Thread {
 		volatile boolean stopFlag;
+		final Object suspendSignal = new Object();
 		volatile boolean suspendFlag;
 
 		/**
@@ -147,8 +153,17 @@ public void run() {
 			while (!stopFlag) {
 				int length = deviceConnection.bulkTransfer(usbEndpoint, bulkReadBuffer, maxPacketSize, 0);
 				if (length > 0) {
-					if (suspendFlag) {
-						continue;
+					synchronized (suspendSignal) {
+						if (suspendFlag) {
+							try {
+								// check the deviceConnection to ignore events while suspending.
+								// Note: Events received within last sleeping(100msec) will be sent to the eventListener.
+								suspendSignal.wait(100);
+							} catch (InterruptedException e) {
+								// ignore exception
+							}
+							continue;
+						}
 					}
 
 					System.arraycopy(bulkReadBuffer, 0, readBuffer, readBufferSize, length);

diff --git a/MIDIDriver/src/jp/kshoji/driver/midi/device/MidiOutputDevice.java b/MIDIDriver/src/jp/kshoji/driver/midi/device/MidiOutputDevice.java
@@ -59,7 +59,7 @@ public MidiOutputDevice(UsbDevice usbDevice, UsbDeviceConnection usbDeviceConnec
 	public void stop() {
 		usbDeviceConnection.releaseInterface(usbInterface);
 
-		waiterThread.suspendFlag = false;
+		resume();
 		waiterThread.stopFlag = true;
 		waiterThread.interrupt();
 
@@ -177,7 +177,7 @@ public void run() {
 				if (suspendFlag) {
 					try {
 						// sleep until interrupted
-						Thread.sleep(500);
+						sleep(500);
 					} catch (InterruptedException e) {
 						// interrupted: event queued, or stopFlag/suspendFlag changed.
 					}
@@ -226,7 +226,7 @@ public void run() {
 				if (queueSize == 0 && !interrupted()) {
 					try {
 						// sleep until interrupted
-						Thread.sleep(500);
+						sleep(500);
 					} catch (InterruptedException e) {
 						// interrupted: event queued, or stopFlag changed.
 					}