[client] Async remote version info fetching

1 files changed, 45 insertions, 41 deletions

diff --git a/dozentenmodul/src/main/java/org/openslx/dozmod/util/ClientVersion.java b/dozentenmodul/src/main/java/org/openslx/dozmod/util/ClientVersion.java
index 31effe85..5ed1fe5d 100644
--- a/dozentenmodul/src/main/java/org/openslx/dozmod/util/ClientVersion.java
+++ b/dozentenmodul/src/main/java/org/openslx/dozmod/util/ClientVersion.java
@@ -13,6 +13,7 @@ import java.util.jar.Manifest;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.output.ByteArrayOutputStream;
 import org.apache.log4j.Logger;
+import org.openslx.dozmod.App;
 import org.openslx.sat.thrift.version.Version;
 import org.openslx.util.Json;
 
@@ -22,26 +23,14 @@ public class ClientVersion {
 
 	private static long localRevisionTime = 0;
 	private static long remoteRevisionTime = 0;
-	private static String localRevision = null;
-	private static String remoteRevision = null;
-	private static String changelog = null;
+	private static String localRevision = "???";
+	private static String remoteRevision = "???";
+	private static String changelog = "???";
+	private static Thread remoteThread = null; 
 
-	private static void init() {
-		if (localRevision == null) {
-			loadLocalVersion();
-		}
-		if (localRevision == null) {
-			localRevision = "???";
-		}
-		if (remoteRevision == null) {
-			loadRemoteVersion("https://bwlp-masterserver.ruf.uni-freiburg.de/dozmod/" + Version.VERSION + "/version.json");
-		}
-		if (remoteRevision == null) {
-			remoteRevision = "???";
-		}
-		if (changelog == null) {
-			changelog = "???";
-		}
+	static  {
+		loadLocalVersion();
+		loadRemoteVersion("https://bwlp-masterserver.ruf.uni-freiburg.de/dozmod/" + Version.VERSION + "/version.json");
 	}
 
 	/**
@@ -50,7 +39,6 @@ public class ClientVersion {
 	 * @return id as String
 	 */
 	public static String getLocalRevision() {
-		init();
 		return localRevision;
 	}
 
@@ -58,7 +46,6 @@ public class ClientVersion {
 	 * @return
 	 */
 	public static long getLocalRevTimestamp() {
-		init();
 		return localRevisionTime;
 	}
 
@@ -68,7 +55,7 @@ public class ClientVersion {
 	 * @return id as String if loading worked, "???" otherwise
 	 */
 	public static String getRemoteRevision() {
-		init();
+		waitRemote();
 		return remoteRevision;
 	}
 
@@ -78,7 +65,7 @@ public class ClientVersion {
 	 * @return timestamp as Long if loading it worked, 0L otherwise
 	 */
 	public static long getRemoteRevTimestamp() {
-		init();
+		waitRemote();
 		return remoteRevisionTime;
 	}
 
@@ -88,7 +75,7 @@ public class ClientVersion {
 	 * @return log as String
 	 */
 	public static String getChangelog() {
-		init();
+		waitRemote();
 		return changelog;
 	}
 
@@ -98,10 +85,10 @@ public class ClientVersion {
 	 * @return true if there is no newer version, false otherwise
 	 */
 	public static boolean isNewest() {
-		init();
 		// if either local or remote version is unknown, just pretend there's no update
 		// as there most likely isn't and we'd just annoy the user
 		// TODO: Report "fail" state so at least on manual update check we can tell that it failed
+		waitRemote();
 		if (localRevisionTime == 0 || remoteRevisionTime == 0)
 			return true;
 		return localRevisionTime >= remoteRevisionTime;
@@ -167,24 +154,41 @@ public class ClientVersion {
 	 * { "timestamp": 1, "revision": 2 }
 	 */
 	private static void loadRemoteVersion(final String urlString) {
-		String json = null;
-		try (InputStream reader = new URL(urlString).openStream()) {
-			ByteArrayOutputStream buffer = new ByteArrayOutputStream();
-			buffer.write(reader);
-			buffer.close();
-			json = new String(buffer.toByteArray(), StandardCharsets.UTF_8);
-		} catch (Exception e) {
-			if (json == null) {
-				LOGGER.error("Could not fetch remote version", e);
-				return;
+		remoteThread = new Thread(new Runnable() {
+			@Override
+			public void run() {
+				App.waitForInit();
+				String json = null;
+				try (InputStream reader = new URL(urlString).openStream()) {
+					ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+					buffer.write(reader);
+					buffer.close();
+					json = new String(buffer.toByteArray(), StandardCharsets.UTF_8);
+				} catch (Exception e) {
+					if (json == null) {
+						LOGGER.error("Could not fetch remote version", e);
+						return;
+					}
+				}
+
+				VersionQuery query = Json.deserialize(json, VersionQuery.class);
+				remoteRevision = query.revision;
+				// seconds timestamp here...
+				remoteRevisionTime = query.timestamp;
+				changelog = query.changelog;
 			}
+		});
+		remoteThread.start();
+	}
+	
+	private static synchronized void waitRemote() {
+		if (remoteThread == null)
+			return;
+		try {
+			remoteThread.join();
+		} catch (InterruptedException e) {
 		}
-
-		VersionQuery query = Json.deserialize(json, VersionQuery.class);
-		remoteRevision = query.revision;
-		// seconds timestamp here...
-		remoteRevisionTime = query.timestamp;
-		changelog = query.changelog;
+		remoteThread = null;
 	}
 
 	/**