Native library: refactored loading of Windows native library from FlatWindowsNativeWindowBorder to FlatNativeLibrary to make it easier to add native libraries for other platforms (for issues #204 and #482)

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

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2022 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.io.File;
+import com.formdev.flatlaf.FlatSystemProperties;
+import com.formdev.flatlaf.util.LoggingFacade;
+import com.formdev.flatlaf.util.NativeLibrary;
+import com.formdev.flatlaf.util.SystemInfo;
+
+/**
+ * Helper class to load FlatLaf native library (.dll, .so or .dylib),
+ * if available for current operating system and CPU architecture.
+ *
+ * @author Karl Tauber
+ * @since 2.3
+ */
+class FlatNativeLibrary
+{
+	private static NativeLibrary nativeLibrary;
+
+	/**
+	 * Loads native library (if available) and returns whether loaded successfully.
+	 * Returns {@code false} if no native library is available.
+	 */
+	static synchronized boolean isLoaded() {
+		initialize();
+		return (nativeLibrary != null) ? nativeLibrary.isLoaded() : false;
+	}
+
+	private static void initialize() {
+		if( nativeLibrary != null )
+			return;
+
+		String libraryName;
+		if( SystemInfo.isWindows_10_orLater && (SystemInfo.isX86 || SystemInfo.isX86_64) ) {
+			// Windows: requires Windows 10 (x86 or x86_64)
+
+			libraryName = "flatlaf-windows-x86";
+			if( SystemInfo.isX86_64 )
+				libraryName += "_64";
+
+			// load jawt native library
+			loadJAWT();
+		} else
+			return; // no native library available for current OS or CPU architecture
+
+		// load native library
+		nativeLibrary = createNativeLibrary( libraryName );
+	}
+
+	private static NativeLibrary createNativeLibrary( String libraryName ) {
+		String libraryPath = System.getProperty( FlatSystemProperties.NATIVE_LIBRARY_PATH );
+		if( libraryPath != null ) {
+			File libraryFile = new File( libraryPath, System.mapLibraryName( libraryName ) );
+			if( libraryFile.exists() )
+				return new NativeLibrary( libraryFile, true );
+			else
+				LoggingFacade.INSTANCE.logSevere( "Did not find external library " + libraryFile + ", using extracted library instead", null );
+		}
+
+		return new NativeLibrary( "com/formdev/flatlaf/natives/" + libraryName, null, true );
+	}
+
+	private static void loadJAWT() {
+		if( SystemInfo.isJava_9_orLater )
+			return;
+
+		// In Java 8, load jawt.dll (part of JRE) explicitly because it
+		// is not found when running application with <jdk>/bin/java.exe.
+		// When using <jdk>/jre/bin/java.exe, it is found.
+		// jawt.dll is located in <jdk>/jre/bin/.
+		// Java 9 and later do not have this problem.
+		try {
+			System.loadLibrary( "jawt" );
+		} catch( UnsatisfiedLinkError ex ) {
+			// log error only if native library jawt.dll not already loaded
+			String message = ex.getMessage();
+			if( message == null || !message.contains( "already loaded in another classloader" ) )
+				LoggingFacade.INSTANCE.logSevere( null, ex );
+		} catch( Exception ex ) {
+			LoggingFacade.INSTANCE.logSevere( null, ex );
+		}
+	}
+}

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

@@ -27,7 +27,6 @@ import java.awt.Window;
 import java.awt.geom.AffineTransform;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
-import java.io.File;
 import java.util.Collections;
 import java.util.IdentityHashMap;
 import java.util.List;
@@ -38,9 +37,7 @@ import javax.swing.Timer;
 import javax.swing.event.ChangeEvent;
 import javax.swing.event.ChangeListener;
 import javax.swing.event.EventListenerList;
-import com.formdev.flatlaf.FlatSystemProperties;
 import com.formdev.flatlaf.util.LoggingFacade;
-import com.formdev.flatlaf.util.NativeLibrary;
 import com.formdev.flatlaf.util.SystemInfo;
 
 //
@@ -84,7 +81,6 @@ class FlatWindowsNativeWindowBorder
 	private Color colorizationColor;
 	private int colorizationColorBalance;
 
-	private static NativeLibrary nativeLibrary;
 	private static FlatWindowsNativeWindowBorder instance;
 
 	static FlatNativeWindowBorder.Provider getInstance() {
@@ -96,31 +92,8 @@ class FlatWindowsNativeWindowBorder
 		if( !SystemInfo.isX86 && !SystemInfo.isX86_64 )
 			return null;
 
-		// load native library
-		if( nativeLibrary == null ) {
-			if( !SystemInfo.isJava_9_orLater ) {
-				// In Java 8, load jawt.dll (part of JRE) explicitly because it
-				// is not found when running application with <jdk>/bin/java.exe.
-				// When using <jdk>/jre/bin/java.exe, it is found.
-				// jawt.dll is located in <jdk>/jre/bin/.
-				// Java 9 and later does not have this problem.
-				try {
-					System.loadLibrary( "jawt" );
-				} catch( UnsatisfiedLinkError ex ) {
-					// log error only if native library jawt.dll not already loaded
-					String message = ex.getMessage();
-					if( message == null || !message.contains( "already loaded in another classloader" ) )
-						LoggingFacade.INSTANCE.logSevere( null, ex );
-				} catch( Exception ex ) {
-					LoggingFacade.INSTANCE.logSevere( null, ex );
-				}
-			}
-
-			nativeLibrary = createNativeLibrary();
-		}
-
 		// check whether native library was successfully loaded
-		if( !nativeLibrary.isLoaded() )
+		if( !FlatNativeLibrary.isLoaded() )
 			return null;
 
 		// create new instance
@@ -129,23 +102,6 @@ class FlatWindowsNativeWindowBorder
 		return instance;
 	}
 
-	private static NativeLibrary createNativeLibrary() {
-		String libraryName = "flatlaf-windows-x86";
-		if( SystemInfo.isX86_64 )
-			libraryName += "_64";
-
-		String libraryPath = System.getProperty( FlatSystemProperties.NATIVE_LIBRARY_PATH );
-		if( libraryPath != null ) {
-			File libraryFile = new File( libraryPath, System.mapLibraryName( libraryName ) );
-			if( libraryFile.exists() )
-				return new NativeLibrary( libraryFile, true );
-			else
-				LoggingFacade.INSTANCE.logSevere( "Did not find external library " + libraryFile + ", using extracted library instead", null );
-		}
-
-		return new NativeLibrary( "com/formdev/flatlaf/natives/" + libraryName, null, true );
-	}
-
 	private FlatWindowsNativeWindowBorder() {
 	}