Use single scheduler for lucene scheduled tasks

pom.xml

@@ -38,7 +38,7 @@
         <dependency>
             <groupId>org.warp</groupId>
             <artifactId>common-utils</artifactId>
-            <version>1.1.1</version>
+            <version>1.1.2</version>
         </dependency>
         <dependency>
             <groupId>javax.xml.bind</groupId>

src/main/java/it/cavallium/dbengine/database/disk/LLLocalLuceneIndex.java

@@ -34,6 +34,7 @@ import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.FSDirectory;
 import org.jetbrains.annotations.Nullable;
+import org.warp.commonutils.concurrency.executor.ScheduledTaskLifecycle;
 import org.warp.commonutils.functional.IOFunction;
 import org.warp.commonutils.type.ShortNamedThreadFactory;
 import it.cavallium.dbengine.database.LLDocument;
@@ -59,14 +60,19 @@ import reactor.util.function.Tuples;
 public class LLLocalLuceneIndex implements LLLuceneIndex {
 
 	private static final LuceneStreamSearcher streamSearcher = new AdaptiveStreamSearcher();
-	private final Duration queryRefreshDebounceTime;
-	private final Duration commitDebounceTime;
+	/**
+	 * Global lucene index scheduler.
+	 * There is only a single thread globally to not overwhelm the disk with
+	 * parallel commits or parallel refreshes.
+	 */
+	private static final ScheduledExecutorService scheduler
+			= Executors.newSingleThreadScheduledExecutor(new ShortNamedThreadFactory("Lucene"));
+
 	private final String luceneIndexName;
 	private final SnapshotDeletionPolicy snapshotter;
 	private final IndexWriter indexWriter;
 	private final SearcherManager searcherManager;
 	private final Directory directory;
-	private final AtomicLong lastSearcherRefresh = new AtomicLong(0);
 	/**
 	 * Last snapshot sequence number. 0 is not used
 	 */
@@ -75,9 +81,10 @@ public class LLLocalLuceneIndex implements LLLuceneIndex {
 	 * Snapshot seq no to index commit point
 	 */
 	private final ConcurrentHashMap<Long, LuceneIndexSnapshot> snapshots = new ConcurrentHashMap<>();
-	private final ScheduledExecutorService scheduler;
 	private final boolean lowMemory;
 
+	private final ScheduledTaskLifecycle scheduledTasksLifecycle;
+
 	public LLLocalLuceneIndex(Path luceneBasePath,
 			String name,
 			TextFieldsAnalyzer analyzer,
@@ -105,20 +112,21 @@ public class LLLocalLuceneIndex implements LLLuceneIndex {
 		}
 		this.indexWriter = new IndexWriter(directory, indexWriterConfig);
 		this.searcherManager = new SearcherManager(indexWriter, false, false, null);
-		this.queryRefreshDebounceTime = queryRefreshDebounceTime;
-		this.commitDebounceTime = commitDebounceTime;
-		this.lastSearcherRefresh.set(System.currentTimeMillis());
-		this.scheduler = Executors.newSingleThreadScheduledExecutor(new ShortNamedThreadFactory("Lucene"));
-		scheduler.scheduleAtFixedRate(this::scheduledCommit,
-				commitDebounceTime.toMillis(),
-				commitDebounceTime.toMillis(),
+
+		// Create scheduled tasks lifecycle manager
+		this.scheduledTasksLifecycle = new ScheduledTaskLifecycle();
+
+		// Start scheduled tasks
+		registerScheduledFixedTask(this::scheduledCommit, commitDebounceTime);
+		registerScheduledFixedTask(this::scheduledQueryRefresh, queryRefreshDebounceTime);
+	}
+
+	private void registerScheduledFixedTask(Runnable task, Duration duration) {
+		scheduledTasksLifecycle.registerScheduledTask(scheduler.scheduleAtFixedRate(task,
+				duration.toMillis(),
+				duration.toMillis(),
 				TimeUnit.MILLISECONDS
-		);
-		scheduler.scheduleAtFixedRate(this::scheduledQueryRefresh,
-				queryRefreshDebounceTime.toMillis(),
-				queryRefreshDebounceTime.toMillis(),
-				TimeUnit.MILLISECONDS
-		);
+		));
 	}
 
 	@Override
@@ -368,17 +376,7 @@ public class LLLocalLuceneIndex implements LLLuceneIndex {
 
 	@Override
 	public void close() throws IOException {
-		scheduler.shutdown();
-		try {
-			scheduler.awaitTermination(10, TimeUnit.MINUTES);
-		} catch (InterruptedException e) {
-			e.printStackTrace();
-		}
-		if (!scheduler.isTerminated()) {
-			System.err.println("Terminating lucene scheduler");
-			scheduler.shutdownNow();
-		}
-		indexWriter.commit();
+		scheduledTasksLifecycle.cancelAndWait();
 		indexWriter.close();
 		directory.close();
 	}