searchbar: fix selection, fix freeze on search text deletion

Author: frauzufall

src/main/java/org/scijava/search/module/ModuleSearcher.java

@@ -29,6 +29,7 @@
 
 package org.scijava.search.module;
 
+import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -68,6 +69,8 @@ public String title() {
 
 	@Override
 	public List<SearchResult> search(final String text, final boolean fuzzy) {
+		if (text.isEmpty()) return Collections.emptyList();
+
 		final String baseDir = //
 			appService.getApp().getBaseDirectory().getAbsolutePath();
 

src/main/java/org/scijava/ui/swing/search/SwingSearchBar.java

@@ -70,10 +70,7 @@
 import javax.swing.ScrollPaneConstants;
 import javax.swing.SwingUtilities;
 import javax.swing.UIManager;
-import javax.swing.border.Border;
-import javax.swing.border.CompoundBorder;
 import javax.swing.border.EmptyBorder;
-import javax.swing.border.LineBorder;
 import javax.swing.event.DocumentEvent;
 import javax.swing.event.DocumentListener;
 import javax.swing.text.html.HTMLDocument;
@@ -553,22 +550,18 @@ private void rebuild() {
 			resultsList.setModel(listModel);
 
 			// TODO: Improve retainment of previous selection.
-			// TODO: find out why this still leads to freezes
-//			if(!searchTerm.isEmpty()) {
-//				System.out.println(searchTerm);
-//				if (previous == null) {
-//					if(listModel.getSize() > 0){
-//						System.out.println( "rebuild 5.1" );
-//						resultsList.setSelectedIndex(firstResultIndex());
-//					}
-//				}
-//				else {
-//					if(listModel.contains(previous)){
-//						System.out.println( "rebuild 5.2" );
-//						resultsList.setSelectedValue(previous, true);
-//					}
-//				}	
-//			}
+			if(!searchTerm.isEmpty()) {
+				if (previous == null) {
+					if(listModel.getSize() > 0){
+						resultsList.setSelectedIndex(firstResultIndex());
+					}
+				}
+				else {
+					if(listModel.contains(previous)){
+						resultsList.setSelectedValue(previous, true);
+					}
+				}
+			}
 		}
 
 		private Component icon(final String iconPath) {