Viewport: use method handle, instead of reflection, to get view UI faster

flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java

@@ -30,9 +30,6 @@ import java.awt.image.ImageProducer;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.io.File;
-import java.lang.invoke.MethodHandle;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.MethodType;
 import java.lang.reflect.Method;
 import java.net.URL;
 import java.util.ArrayList;
@@ -78,6 +75,7 @@ import com.formdev.flatlaf.ui.FlatNativeWindowBorder;
 import com.formdev.flatlaf.ui.FlatPopupFactory;
 import com.formdev.flatlaf.ui.FlatRootPaneUI;
 import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.ui.JavaCompatibility2;
 import com.formdev.flatlaf.ui.FlatStylingSupport.StyleableUI;
 import com.formdev.flatlaf.util.FontUtils;
 import com.formdev.flatlaf.util.GrayFilter;
@@ -1289,8 +1287,8 @@ public abstract class FlatLaf
 	 * @since 2.5
 	 */
 	public static Map<String, Class<?>> getStyleableInfos( JComponent c ) {
-		StyleableUI ui = getStyleableUI( c );
-		return (ui != null) ? ui.getStyleableInfos( c ) : null;
+		ComponentUI ui = JavaCompatibility2.getUI( c );
+		return (ui instanceof StyleableUI) ? ((StyleableUI)ui).getStyleableInfos( c ) : null;
 	}
 
 	/**
@@ -1302,41 +1300,10 @@ public abstract class FlatLaf
 	 */
 	@SuppressWarnings( "unchecked" )
 	public static <T> T getStyleableValue( JComponent c, String key ) {
-		StyleableUI ui = getStyleableUI( c );
-		return (ui != null) ? (T) ui.getStyleableValue( c, key ) : null;
+		ComponentUI ui = JavaCompatibility2.getUI( c );
+		return (ui instanceof StyleableUI) ? (T) ((StyleableUI)ui).getStyleableValue( c, key ) : null;
 	}
 
-	private static StyleableUI getStyleableUI( JComponent c ) {
-		if( !getUIMethodInitialized ) {
-			getUIMethodInitialized = true;
-
-			if( SystemInfo.isJava_9_orLater ) {
-				try {
-					// JComponent.getUI() is available since Java 9
-					getUIMethod = MethodHandles.lookup().findVirtual( JComponent.class, "getUI",
-						MethodType.methodType( ComponentUI.class ) );
-				} catch( Exception ex ) {
-					// ignore
-				}
-			}
-		}
-
-		try {
-			Object ui;
-			if( getUIMethod != null )
-				ui = getUIMethod.invoke( c );
-			else
-				ui = c.getClass().getMethod( "getUI" ).invoke( c );
-			return (ui instanceof StyleableUI) ? (StyleableUI) ui : null;
-		} catch( Throwable ex ) {
-			// ignore
-			return null;
-		}
-	}
-
-	private static boolean getUIMethodInitialized;
-	private static MethodHandle getUIMethod;
-
 	/**
 	 * Returns the preferred font family to be used for (nearly) all fonts; or {@code null}.
 	 *

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatViewportUI.java

@@ -18,7 +18,6 @@ package com.formdev.flatlaf.ui;
 
 import java.awt.Component;
 import java.awt.Graphics;
-import java.lang.reflect.Method;
 import javax.swing.JComponent;
 import javax.swing.JViewport;
 import javax.swing.plaf.ComponentUI;
@@ -48,14 +47,9 @@ public class FlatViewportUI
 
 		Component view = ((JViewport)c).getView();
 		if( view instanceof JComponent ) {
-			try {
-				Method m = view.getClass().getMethod( "getUI" );
-				Object ui = m.invoke( view );
+			ComponentUI ui = JavaCompatibility2.getUI( (JComponent) view );
 			if( ui instanceof ViewportPainter )
 				((ViewportPainter)ui).paintViewport( g, (JComponent) view, (JViewport) c );
-			} catch( Exception ex ) {
-				// ignore
-			}
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/JavaCompatibility2.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2024 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.lang.reflect.Method;
+import javax.swing.JComponent;
+import javax.swing.JList;
+import javax.swing.JPanel;
+import javax.swing.JTable;
+import javax.swing.JTree;
+import javax.swing.plaf.ComponentUI;
+import javax.swing.text.JTextComponent;
+import com.formdev.flatlaf.util.LoggingFacade;
+import com.formdev.flatlaf.util.SystemInfo;
+
+/**
+ * Provides Java version compatibility methods.
+ * <p>
+ * WARNING: This is private API and may change.
+ *
+ * @author Karl Tauber
+ * @since 3.3
+ */
+public class JavaCompatibility2
+{
+	private static boolean getUIMethodInitialized;
+	private static MethodHandle getUIMethod;
+
+	/**
+	 * Java 8: getUI() method on various components (e.g. JButton, JList, etc)
+	 * <br>
+	 * Java 9: javax.swing.JComponent.getUI()
+	 */
+	public static ComponentUI getUI( JComponent c ) {
+		try {
+			// Java 9+
+			if( SystemInfo.isJava_9_orLater ) {
+				if( !getUIMethodInitialized ) {
+					getUIMethodInitialized = true;
+
+					try {
+						MethodType mt = MethodType.methodType( ComponentUI.class, new Class[0] );
+						getUIMethod = MethodHandles.publicLookup().findVirtual( JComponent.class, "getUI", mt );
+					} catch( Exception ex ) {
+						// ignore
+						LoggingFacade.INSTANCE.logSevere( null, ex );
+					}
+				}
+
+				if( getUIMethod != null )
+					return (ComponentUI) getUIMethod.invoke( c );
+			}
+
+			// components often used (e.g. as view in scroll panes)
+			if( c instanceof JPanel )
+				return ((JPanel)c).getUI();
+			if( c instanceof JList )
+				return ((JList<?>)c).getUI();
+			if( c instanceof JTable )
+				return ((JTable)c).getUI();
+			if( c instanceof JTree )
+				return ((JTree)c).getUI();
+			if( c instanceof JTextComponent )
+				return ((JTextComponent)c).getUI();
+
+			// Java 8 and fallback
+			Method m = c.getClass().getMethod( "getUI" );
+			return (ComponentUI) m.invoke( c );
+		} catch( Throwable ex ) {
+			// ignore
+			return null;
+		}
+	}
+}