[feature] When opening the Query Dialog, load the list of Collections lazily and in a background thread

Author: adamretter

exist-core/src/main/java/org/exist/client/QueryDialog.java

@@ -57,9 +57,12 @@
 import javax.swing.JToolBar;
 import javax.swing.SpinnerNumberModel;
 import javax.swing.border.BevelBorder;
+import javax.swing.event.PopupMenuEvent;
+import javax.swing.event.PopupMenuListener;
 import javax.xml.transform.OutputKeys;
 
 import org.exist.security.PermissionDeniedException;
+import org.exist.util.Holder;
 import org.exist.xmldb.EXistXQueryService;
 import org.exist.xmldb.LocalCollection;
 import org.exist.xmldb.UserManagementService;
@@ -84,6 +87,11 @@ public class QueryDialog extends JFrame {
 
     private static final long serialVersionUID = 1L;
 
+    private static final AtomicInteger QUERY_THREAD_ID = new AtomicInteger();
+    private static final AtomicInteger GET_COLLECTIONS_THREAD_ID = new AtomicInteger();
+
+    private static final String LOADING_INDICATOR = "Loading...";
+
     private InteractiveClient client;
     private Collection collection;
     private Properties properties;
@@ -334,24 +342,48 @@ private JComponent createQueryBox() {
         label = new JLabel(Messages.getString("QueryDialog.contextlabel"));
         optionsPanel.add(label);
 
-        final List<String> data = new ArrayList<>();
+        final Holder<Boolean> addedLoadingIndicator = new Holder<>(false);
+        final List<String> collectionsList = new ArrayList<>();
         try {
-            final Collection root = client.getCollection(XmldbURI.ROOT_COLLECTION);
-            data.add(collection.getName());
-            getCollections(root, collection, data);
+            final String currentCollectionName = collection.getName();
+
+            collectionsList.add(currentCollectionName);
+
+            collections = new JComboBox<>(new java.util.Vector<>(collectionsList));
+
+            collections.addPopupMenuListener(new PopupMenuListener() {
+                @Override
+                public void popupMenuWillBecomeVisible(final PopupMenuEvent e) {
+                    if (!addedLoadingIndicator.value) {
+                        collections.addItem(LOADING_INDICATOR);
+                        addedLoadingIndicator.value = true;
+
+                        final GetCollectionsListRunnable getCollectionsListRunnable = new GetCollectionsListRunnable(currentCollectionName, collections);
+                        final Thread getCollectionsListThread = client.newClientThread("get-collections-list-" + GET_COLLECTIONS_THREAD_ID.getAndIncrement(), getCollectionsListRunnable);
+                        getCollectionsListThread.start();
+                    }
+                }
+
+                @Override
+                public void popupMenuWillBecomeInvisible(final PopupMenuEvent e) {
+                }
+
+                @Override
+                public void popupMenuCanceled(final PopupMenuEvent e) {
+                }
+            });
         } catch (final XMLDBException e) {
             ClientFrame.showErrorMessage(
                     Messages.getString("QueryDialog.collectionretrievalerrormessage") + ".", e);
         }
-        collections = new JComboBox<>(new java.util.Vector<>(data));
-        collections.setSelectedIndex(0);
+
         collections.addActionListener(e -> {
             final int p = collections.getSelectedIndex();
             final String context;
             if (p == -1) {
                 context = "/db";
             } else {
-                context =  data.get(p);
+                context =  collectionsList.get(p);
             }
             try {
                 collection = client.getCollection(context);
@@ -372,8 +404,8 @@ private JComponent createQueryBox() {
         return tabs;
     }
 
-    private List<String> getCollections(final Collection root, final Collection collection, final List<String> collectionsList) throws XMLDBException {
-        if (!collection.getName().equals(root.getName())) {
+    private static List<String> getCollections(final Collection root, final String currentCollection, final List<String> collectionsList) throws XMLDBException {
+        if (!currentCollection.equals(root.getName())) {
             collectionsList.add(root.getName());
         }
         final String[] childCollections = root.listChildCollections();
@@ -392,7 +424,7 @@ private List<String> getCollections(final Collection root, final Collection coll
                 continue;
             }
             try {
-                getCollections(child, collection, collectionsList);
+                getCollections(child, currentCollection, collectionsList);
             } catch (Exception ee) {
                 System.out.println("Corrupted resource/collection skipped: " + child != null ? child.getName() != null ? child.getName() : "unknown" : "unknown");
                 continue;
@@ -470,8 +502,6 @@ private void save(String stringToSave, String fileCategory) {
         }
     }
 
-    private static final AtomicInteger queryThreadId = new AtomicInteger();
-
     private QueryRunnable doQuery() {
         final String xpath = query.getText();
         if (xpath.length() == 0) {
@@ -480,7 +510,7 @@ private QueryRunnable doQuery() {
         resultDisplay.setText("");
 
         final QueryRunnable queryRunnable = new QueryRunnable(xpath);
-        final Thread queryThread = client.newClientThread("query-" + queryThreadId.getAndIncrement(), queryRunnable);
+        final Thread queryThread = client.newClientThread("query-" + QUERY_THREAD_ID.getAndIncrement(), queryRunnable);
         queryThread.start();
         return queryRunnable;
     }
@@ -665,4 +695,30 @@ private void addQuery(String query) {
         }
         history.addElement(Integer.toString(history.getSize() + 1) + ". " + query);
     }
+
+    private class GetCollectionsListRunnable implements Runnable {
+        private final String currentCollection;
+        private final JComboBox<String> collections;
+
+        public GetCollectionsListRunnable(final String currentCollection, final JComboBox<String> collections) {
+            this.currentCollection = currentCollection;
+            this.collections = collections;
+        }
+
+        @Override
+        public void run() {
+            final List<String> collectionsList = new ArrayList<>();
+            collectionsList.add(currentCollection);
+
+            try {
+                final Collection root = client.getCollection(XmldbURI.ROOT_COLLECTION);
+                getCollections(root, currentCollection, collectionsList);
+
+                collections.setModel(new DefaultComboBoxModel(new java.util.Vector<>(collectionsList)));
+            } catch (final XMLDBException e) {
+                ClientFrame.showErrorMessage(
+                        Messages.getString("QueryDialog.collectionretrievalerrormessage") + ".", e);
+            }
+        }
+    }
 }