[server] Foundations for the maintenance module

1 files changed, 58 insertions, 0 deletions

diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/maintenance/Maintenance.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/maintenance/Maintenance.java
new file mode 100644
index 00000000..98f7f09b
--- /dev/null
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/maintenance/Maintenance.java
@@ -0,0 +1,58 @@
+package org.openslx.bwlp.sat.maintenance;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+import org.apache.log4j.Logger;
+
+public class Maintenance extends Thread {
+
+	private static final Logger LOGGER = Logger.getLogger(Maintenance.class);
+
+	private static Maintenance worker = null;
+
+	private static BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>(50);
+
+	private Maintenance() {
+	}
+
+	private synchronized static void ensureRunning() {
+		if (worker == null || !worker.isAlive()) {
+			worker = new Maintenance();
+			worker.start();
+		}
+	}
+
+	public static void submit(Runnable job) throws InterruptedException {
+		ensureRunning();
+		queue.put(job);
+	}
+
+	public static boolean trySubmit(Runnable job) {
+		ensureRunning();
+		return queue.offer(job);
+	}
+
+	@Override
+	public void run() {
+		LOGGER.info("Maintenance Thread started");
+		try {
+			Runnable job = queue.take();
+			runJob(job);
+		} catch (InterruptedException e) {
+			LOGGER.warn("Maintenance Thread was interrupted!", e);
+			if (!queue.isEmpty()) {
+				ensureRunning();
+			}
+		}
+	}
+
+	private void runJob(Runnable job) {
+		try {
+			job.run();
+		} catch (Throwable t) {
+			LOGGER.warn("Uncaught exception in job '" + job.getClass().getSimpleName() + "'", t);
+		}
+	}
+
+}