#919 - io.ebean package initial

src/main/java/io/ebeaninternal/server/lib/DaemonScheduleThreadPool.java

@@ -0,0 +1,59 @@
+package io.ebeaninternal.server.lib;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Daemon based ScheduleThreadPool.
+ * <p>
+ * Uses Daemon threads and hooks into shutdown event.
+ * </p>
+ */
+public final class DaemonScheduleThreadPool extends ScheduledThreadPoolExecutor {
+
+  private static final Logger logger = LoggerFactory.getLogger(DaemonScheduleThreadPool.class);
+
+  private final String namePrefix;
+
+  private final int shutdownWaitSeconds;
+
+  /**
+   * Construct the DaemonScheduleThreadPool.
+   */
+  public DaemonScheduleThreadPool(int coreSize, int shutdownWaitSeconds, String namePrefix) {
+    super(coreSize, new DaemonThreadFactory(namePrefix));
+    this.namePrefix = namePrefix;
+    this.shutdownWaitSeconds = shutdownWaitSeconds;
+  }
+
+  /**
+   * Shutdown this thread pool nicely if possible.
+   * <p>
+   * This will wait a maximum of 20 seconds before terminating any threads still
+   * working.
+   * </p>
+   */
+  public void shutdown() {
+    synchronized (this) {
+      if (super.isShutdown()) {
+        logger.debug("DaemonScheduleThreadPool {} already shut down", namePrefix);
+        return;
+      }
+      try {
+        logger.debug("DaemonScheduleThreadPool {} shutting down...", namePrefix);
+        super.shutdown();
+        if (!super.awaitTermination(shutdownWaitSeconds, TimeUnit.SECONDS)) {
+          logger.info("DaemonScheduleThreadPool shut down timeout exceeded. Terminating running threads.");
+          super.shutdownNow();
+        }
+
+      } catch (Exception e) {
+        logger.error("Error during shutdown of " + namePrefix, e);
+        e.printStackTrace();
+      }
+    }
+  }
+}