Improve performance by throttling database change events

CHANGELOG.md

@@ -18,6 +18,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an issue where the Medline fetcher was only working when JabRef was running from source. [#5645](https://github.com/JabRef/jabref/issues/5645)
 - We fixed some visual issues in the dark theme. [#5764](https://github.com/JabRef/jabref/pull/5764) [#5753](https://github.com/JabRef/jabref/issues/5753)
 - We fixed an issue where non-default previews didn't handle unicode characters. [#5779](https://github.com/JabRef/jabref/issues/5779)
+- We improved the performance, especially changing field values in the entry should feel smoother now.
 - We fixed an issue where the ampersand character wasn't rendering correctly on previews. [#3840](https://github.com/JabRef/jabref/issues/3840)
 - We fixed an issue where an erroneous "The library has been modified by another program" message was shown when saving. [#4877](https://github.com/JabRef/jabref/issues/4877)
 - We fixed an issue where the file extension was missing after downloading a file (we now fall-back to pdf). [#5816](https://github.com/JabRef/jabref/issues/5816)

src/main/java/org/jabref/gui/groups/GroupNodeViewModel.java

@@ -28,6 +28,7 @@
 import org.jabref.gui.util.TaskExecutor;
 import org.jabref.logic.groups.DefaultGroupsFactory;
 import org.jabref.logic.layout.format.LatexToUnicodeFormatter;
+import org.jabref.logic.util.DelayTaskThrottler;
 import org.jabref.model.FieldChange;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.BibEntry;
@@ -56,6 +57,7 @@ public class GroupNodeViewModel {
     private final TaskExecutor taskExecutor;
     private final CustomLocalDragboard localDragBoard;
     private final ObservableList<BibEntry> entriesList;
+    private final DelayTaskThrottler throttler;
 
     public GroupNodeViewModel(BibDatabaseContext databaseContext, StateManager stateManager, TaskExecutor taskExecutor, GroupTreeNode groupNode, CustomLocalDragboard localDragBoard) {
         this.databaseContext = Objects.requireNonNull(databaseContext);
@@ -88,6 +90,7 @@ public GroupNodeViewModel(BibDatabaseContext databaseContext, StateManager state
         // The wrapper created by the FXCollections will set a weak listener on the wrapped list. This weak listener gets garbage collected. Hence, we need to maintain a reference to this list.
         entriesList = databaseContext.getDatabase().getEntries();
         entriesList.addListener(this::onDatabaseChanged);
+        throttler = new DelayTaskThrottler(1000);
 
         ObservableList<Boolean> selectedEntriesMatchStatus = EasyBind.map(stateManager.getSelectedEntries(), groupNode::matches);
         anySelectedEntriesMatched = BindingsHelper.any(selectedEntriesMatchStatus, matched -> matched);
@@ -218,7 +221,7 @@ public GroupTreeNode getGroupNode() {
      * Gets invoked if an entry in the current database changes.
      */
     private void onDatabaseChanged(ListChangeListener.Change<? extends BibEntry> change) {
-        calculateNumberOfMatches();
+        throttler.schedule(this::calculateNumberOfMatches);
     }
 
     private void calculateNumberOfMatches() {

src/main/java/org/jabref/logic/autosaveandbackup/AutosaveManager.java

@@ -2,11 +2,9 @@
 
 import java.util.HashSet;
 import java.util.Set;
-import java.util.concurrent.Future;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 
+import org.jabref.logic.util.DelayTaskThrottler;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.database.event.AutosaveEvent;
 import org.jabref.model.database.event.BibDatabaseContextChangedEvent;
@@ -25,40 +23,34 @@
 public class AutosaveManager {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(AutosaveManager.class);
-    private static final int AUTO_SAVE_DELAY = 200;
 
     private static Set<AutosaveManager> runningInstances = new HashSet<>();
 
     private final BibDatabaseContext bibDatabaseContext;
-    private final ScheduledExecutorService executor;
+
     private final EventBus eventBus;
     private final CoarseChangeFilter changeFilter;
-    private Future<?> scheduledSaveAction;
+    private final DelayTaskThrottler throttler;
 
     private AutosaveManager(BibDatabaseContext bibDatabaseContext) {
         this.bibDatabaseContext = bibDatabaseContext;
-        ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1);
-        executor.setRemoveOnCancelPolicy(true); // This prevents memory leaks
-        this.executor = executor;
+        this.throttler = new DelayTaskThrottler(2000);
         this.eventBus = new EventBus();
         this.changeFilter = new CoarseChangeFilter(bibDatabaseContext);
         changeFilter.registerListener(this);
     }
 
     @Subscribe
     public synchronized void listen(@SuppressWarnings("unused") BibDatabaseContextChangedEvent event) {
-        if (scheduledSaveAction != null) {
-            scheduledSaveAction.cancel(false);
-        }
-        scheduledSaveAction = executor.schedule(() -> {
+        throttler.schedule(() -> {
             eventBus.post(new AutosaveEvent());
-        }, AUTO_SAVE_DELAY, TimeUnit.MILLISECONDS);
+        });
     }
 
     private void shutdown() {
         changeFilter.unregisterListener(this);
         changeFilter.shutdown();
-        executor.shutdown();
+        throttler.shutdown();
     }
 
     /**

src/main/java/org/jabref/logic/autosaveandbackup/BackupManager.java

@@ -8,17 +8,14 @@
 import java.util.HashSet;
 import java.util.Optional;
 import java.util.Set;
-import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 
 import org.jabref.logic.bibtex.InvalidFieldValueException;
 import org.jabref.logic.exporter.AtomicFileWriter;
 import org.jabref.logic.exporter.BibtexDatabaseWriter;
 import org.jabref.logic.exporter.SavePreferences;
+import org.jabref.logic.util.DelayTaskThrottler;
 import org.jabref.logic.util.io.FileUtil;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.database.event.BibDatabaseContextChangedEvent;
@@ -46,17 +43,15 @@ public class BackupManager {
 
     private final BibDatabaseContext bibDatabaseContext;
     private final JabRefPreferences preferences;
-    private final ExecutorService executor;
-    private final Runnable backupTask = () -> determineBackupPath().ifPresent(this::performBackup);
+    private final DelayTaskThrottler throttler;
     private final CoarseChangeFilter changeFilter;
     private final BibEntryTypesManager entryTypesManager;
 
     private BackupManager(BibDatabaseContext bibDatabaseContext, BibEntryTypesManager entryTypesManager, JabRefPreferences preferences) {
         this.bibDatabaseContext = bibDatabaseContext;
         this.entryTypesManager = entryTypesManager;
         this.preferences = preferences;
-        BlockingQueue<Runnable> workerQueue = new ArrayBlockingQueue<>(1);
-        this.executor = new ThreadPoolExecutor(1, 1, 0, TimeUnit.SECONDS, workerQueue);
+        this.throttler = new DelayTaskThrottler(15000);
 
         changeFilter = new CoarseChangeFilter(bibDatabaseContext);
         changeFilter.registerListener(this);
@@ -71,8 +66,6 @@ static Path getBackupPath(Path originalPath) {
      * As long as no database file is present in {@link BibDatabaseContext}, the {@link BackupManager} will do nothing.
      *
      * @param bibDatabaseContext Associated {@link BibDatabaseContext}
-     * @param entryTypesManager
-     * @param preferences
      */
     public static BackupManager start(BibDatabaseContext bibDatabaseContext, BibEntryTypesManager entryTypesManager, JabRefPreferences preferences) {
         BackupManager backupManager = new BackupManager(bibDatabaseContext, entryTypesManager, preferences);
@@ -151,11 +144,7 @@ public synchronized void listen(@SuppressWarnings("unused") BibDatabaseContextCh
     }
 
     private void startBackupTask() {
-        try {
-            executor.submit(backupTask);
-        } catch (RejectedExecutionException e) {
-            LOGGER.debug("Rejecting while another backup process is already running.");
-        }
+        throttler.schedule(() -> determineBackupPath().ifPresent(this::performBackup));
     }
 
     /**
@@ -165,7 +154,7 @@ private void startBackupTask() {
     private void shutdown() {
         changeFilter.unregisterListener(this);
         changeFilter.shutdown();
-        executor.shutdown();
+        throttler.shutdown();
         determineBackupPath().ifPresent(this::deleteBackupFile);
     }
 

src/main/java/org/jabref/logic/util/DelayTaskThrottler.java

@@ -0,0 +1,51 @@
+package org.jabref.logic.util;
+
+import java.util.concurrent.Future;
+import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class allows to throttle a list of tasks.
+ * Use case: you have an event that occurs often, and every time you want to invoke the same task.
+ * However, if a lot of events happen in a relatively short time span, then only one task should be invoked.
+ *
+ * @implNote Once {@link #schedule(Runnable)} is called, the task is delayed for a given time span.
+ *         If during this time, {@link #schedule(Runnable)} is called again, then the original task is canceled and the new one scheduled.
+ */
+public class DelayTaskThrottler {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(DelayTaskThrottler.class);
+
+    private final ScheduledThreadPoolExecutor executor;
+    private final int delay;
+
+    private Future<?> scheduledTask;
+
+    /**
+     * @param delay delay in milliseconds
+     */
+    public DelayTaskThrottler(int delay) {
+        this.delay = delay;
+        this.executor = new ScheduledThreadPoolExecutor(1);
+        this.executor.setRemoveOnCancelPolicy(true);
+    }
+
+    public void schedule(Runnable command) {
+        if (scheduledTask != null) {
+            scheduledTask.cancel(false);
+        }
+        try {
+            scheduledTask = executor.schedule(command, delay, TimeUnit.MILLISECONDS);
+        } catch (RejectedExecutionException e) {
+            LOGGER.debug("Rejecting while another process is already running.");
+        }
+    }
+
+    public void shutdown() {
+        executor.shutdown();
+    }
+}