Better mouse position caching impl

protegeproject · Jan 17, 2019 · c87f152 · c87f152
1 parent 7551bd7
commit c87f152
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Showing 2 changed files with 60 additions and 9 deletions.
diff --git a/protege-editor-core/src/main/java/org/protege/editor/core/ui/list/MList.java b/protege-editor-core/src/main/java/org/protege/editor/core/ui/list/MList.java
@@ -1,6 +1,7 @@
 package org.protege.editor.core.ui.list;
 
 import org.protege.editor.core.ui.util.UIUtil;
+import org.protege.editor.owl.ui.util.MousePositionCache;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -79,9 +80,7 @@ public String getName() {
 
     public int lastMousePositionCellIndex = -1;
 
-    private Point cachedMousePosition = null;
-
-    private boolean cachedMousePositionStale = true;
+    private final MousePositionCache mousePositionCache;
 
     public MList() {
         ListCellRenderer renderer = this.getCellRenderer();
@@ -95,6 +94,7 @@ public void mouseMoved(MouseEvent e) {
                 handleMouseMoved();
             }
         };
+        mousePositionCache = MousePositionCache.createAndInstall(this);
         this.addMouseMotionListener(mouseMovementListener);
         MouseListener mouseButtonListener = new MouseAdapter() {
             @Override
@@ -151,7 +151,6 @@ protected void clearCellHeightCache() {
 
 
     private void handleMouseMoved() {
-        cachedMousePositionStale = true;
         if (MList.this.getModel().getSize() > 0) {
         	    // only repaint all the cells the mouse has moved over
         	    Rectangle dirty = getCellBounds(lastMousePositionCellIndex, lastMousePositionCellIndex);
@@ -512,11 +511,7 @@ private Color getButtonColor(MListButton button) {
 
     @Nullable
     private Point getCachedMousePosition() {
-        if(cachedMousePositionStale) {
-            cachedMousePosition = getMousePosition();
-            cachedMousePositionStale = false;
-        }
-        return cachedMousePosition;
+        return mousePositionCache.getMousePosition();
     }
 
 }
diff --git a/protege-editor-core/src/main/java/org/protege/editor/owl/ui/util/MousePositionCache.java b/protege-editor-core/src/main/java/org/protege/editor/owl/ui/util/MousePositionCache.java
@@ -0,0 +1,56 @@
+package org.protege.editor.owl.ui.util;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.awt.*;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseMotionAdapter;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Matthew Horridge
+ * Stanford Center for Biomedical Informatics Research
+ * 2019-01-17
+ */
+public class MousePositionCache {
+
+    @Nonnull
+    private final Component component;
+
+    private boolean stale = true;
+
+    private Point cachedPosition = null;
+
+    private MousePositionCache(@Nonnull Component component) {
+        this.component = checkNotNull(component);
+    }
+
+    public static MousePositionCache createAndInstall(@Nonnull Component component) {
+        MousePositionCache cache = new MousePositionCache(component);
+        cache.attacheListeners();
+        return cache;
+    }
+
+    private void attacheListeners() {
+        component.addMouseMotionListener(new MouseMotionAdapter() {
+            @Override
+            public void mouseMoved(MouseEvent e) {
+                markAsStale();
+            }
+        });
+    }
+
+    private void markAsStale() {
+        stale = true;
+    }
+
+    @Nullable
+    public Point getMousePosition() {
+        if(stale) {
+            cachedPosition = component.getMousePosition();
+            stale = false;
+        }
+        return cachedPosition;
+    }
+}