introduce ColoredItem interface

GitOrigin-RevId: 1a27db56d5046eb2e0b0f3241b354078088f80c6

platform/platform-api/src/com/intellij/ui/components/WideSelectionListUI.java

@@ -1,8 +1,11 @@
 // Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.ui.components;
 
+import com.intellij.openapi.util.ColoredItem;
 import com.intellij.ui.list.ListCellBackgroundSupplier;
 import com.intellij.util.ui.UIUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import javax.swing.plaf.ComponentUI;
@@ -36,11 +39,7 @@ public final class WideSelectionListUI extends BasicListUI {
       boolean selected = selectionModel.isSelectedIndex(row);
       boolean focused = row == leadSelectionIndex && list.hasFocus();
       Object value = model.getElementAt(row);
-      Color background = null;
-      if (list instanceof ListCellBackgroundSupplier) {
-        //noinspection unchecked
-        background = ((ListCellBackgroundSupplier<Object>)list).getCellBackground(value, row);
-      }
+      Color background = getBackground(list, value, row);
       if (background != null) {
         g.setColor(background);
         g.fillRect(rowBounds.x, rowBounds.y, rowBounds.width, rowBounds.height);
@@ -57,6 +56,20 @@ public final class WideSelectionListUI extends BasicListUI {
     super.paintCell(g, row, rowBounds, renderer, model, selectionModel, leadSelectionIndex);
   }
 
+  @Nullable
+  private static Color getBackground(@NotNull JList list, @Nullable Object value, int row) {
+    if (value instanceof ColoredItem) {
+      Color background = ((ColoredItem)value).getColor();
+      if (background != null) return background;
+    }
+    if (list instanceof ListCellBackgroundSupplier) {
+      //noinspection unchecked
+      Color background = ((ListCellBackgroundSupplier<Object>)list).getCellBackground(value, row);
+      if (background != null) return background;
+    }
+    return null;
+  }
+
   private static void paintRenderer(Graphics g, int x, int y, int width, int height, Component owner, Component renderer) {
     g.clipRect(0, y, owner.getWidth(), height);
     paintBackground(g, y, height, owner, renderer);

platform/platform-impl/src/com/intellij/ui/tree/ui/DefaultTreeUI.java

@@ -2,6 +2,7 @@
 package com.intellij.ui.tree.ui;
 
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.util.ColoredItem;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.SystemInfo;
 import com.intellij.ui.components.JBScrollPane;
@@ -66,6 +67,10 @@ public final class DefaultTreeUI extends BasicTreeUI {
       return UIUtil.getTreeSelectionBackground(tree.hasFocus() || Boolean.TRUE.equals(property));
     }
     Object node = TreeUtil.getLastUserObject(path);
+    if (node instanceof ColoredItem) {
+      Color background = ((ColoredItem)node).getColor();
+      if (background != null) return background;
+    }
     if (node instanceof TreeNodeBackgroundSupplier) {
       TreeNodeBackgroundSupplier supplier = (TreeNodeBackgroundSupplier)node;
       Color background = supplier.getNodeBackground(row);

platform/util/src/com/intellij/openapi/util/ColoredItem.java

@@ -0,0 +1,14 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.openapi.util;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.awt.*;
+
+/**
+ * @author gregsh
+ */
+public interface ColoredItem {
+  @Nullable
+  Color getColor();
+}