Simplified initialization of lazy singletons.

core/src/main/java/com/github/weisj/darklaf/color/DarkColorModelCMYK.java

@@ -26,6 +26,8 @@ package com.github.weisj.darklaf.color;
 
 import java.awt.*;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 /**
  * @author Jannis Weis
  */
@@ -34,11 +36,10 @@ public class DarkColorModelCMYK extends DarkColorModel {
     private static final int[] cmyk = new int[4];
     private static final int[] rgb = new int[3];
 
-    private static DarkColorModelCMYK instance;
+    private static final LazyValue<DarkColorModelCMYK> instance = new LazyValue<>(DarkColorModelCMYK::new);
 
     public static DarkColorModelCMYK getInstance() {
-        if (instance == null) instance = new DarkColorModelCMYK();
-        return instance;
+        return instance.get();
     }
 
     public DarkColorModelCMYK() {

core/src/main/java/com/github/weisj/darklaf/color/DarkColorModelHSB.java

@@ -26,6 +26,8 @@ package com.github.weisj.darklaf.color;
 
 import java.awt.*;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 /**
  * @author Jannis Weis
  */
@@ -34,11 +36,10 @@ public class DarkColorModelHSB extends DarkColorModel {
     private static final float[] hsvVals = new float[3];
     private static final int[] hsb = new int[3];
 
-    private static DarkColorModelHSB instance;
+    private static final LazyValue<DarkColorModelHSB> instance = new LazyValue<>(DarkColorModelHSB::new);
 
     public static DarkColorModelHSB getInstance() {
-        if (instance == null) instance = new DarkColorModelHSB();
-        return instance;
+        return instance.get();
     }
 
     public DarkColorModelHSB() {

core/src/main/java/com/github/weisj/darklaf/color/DarkColorModelHSL.java

@@ -26,6 +26,8 @@ package com.github.weisj.darklaf.color;
 
 import java.awt.*;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 /**
  * @author Jannis Weis
  */
@@ -34,11 +36,10 @@ public class DarkColorModelHSL extends DarkColorModel {
     private static final int[] hsl = new int[3];
     private static final int[] rgb = new int[3];
 
-    private static DarkColorModelHSL instance;
+    private static final LazyValue<DarkColorModelHSL> instance = new LazyValue<>(DarkColorModelHSL::new);
 
     public static DarkColorModelHSL getInstance() {
-        if (instance == null) instance = new DarkColorModelHSL();
-        return instance;
+        return instance.get();
     }
 
     public DarkColorModelHSL() {

core/src/main/java/com/github/weisj/darklaf/color/DarkColorModelRGB.java

@@ -26,13 +26,14 @@ package com.github.weisj.darklaf.color;
 
 import java.awt.*;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 public class DarkColorModelRGB extends DarkColorModel {
 
-    private static DarkColorModelRGB instance;
+    private static final LazyValue<DarkColorModelRGB> instance = new LazyValue<>(DarkColorModelRGB::new);
 
     public static DarkColorModelRGB getInstance() {
-        if (instance == null) instance = new DarkColorModelRGB();
-        return instance;
+        return instance.get();
     }
 
     public DarkColorModelRGB() {

core/src/main/java/com/github/weisj/darklaf/components/tooltip/TooltipAwareButton.java

@@ -28,10 +28,14 @@ import javax.swing.*;
 
 import com.github.weisj.darklaf.ui.tooltip.DarkTooltipUI;
 import com.github.weisj.darklaf.util.Alignment;
+import com.github.weisj.darklaf.util.LazyValue;
 
 public class TooltipAwareButton extends JButton implements ToolTipAware {
 
-    private ToolTipContext context;
+    private final LazyValue<ToolTipContext> context = new LazyValue<>(() -> new ToolTipContext().setAlignment(Alignment.SOUTH)
+                                                                                                .setCenterAlignment(Alignment.SOUTH)
+                                                                                                .setAlignInside(false)
+                                                                                                .setIgnoreBorder(true));
 
     public TooltipAwareButton() {
         this(null, null);
@@ -62,12 +66,6 @@ public class TooltipAwareButton extends JButton implements ToolTipAware {
 
     @Override
     public ToolTipContext getToolTipContext() {
-        if (context == null) {
-            context = new ToolTipContext().setAlignment(Alignment.SOUTH)
-                                          .setCenterAlignment(Alignment.SOUTH)
-                                          .setAlignInside(false)
-                                          .setIgnoreBorder(true);
-        }
-        return context;
+        return context.get();
     }
 }

core/src/main/java/com/github/weisj/darklaf/components/tooltip/TooltipAwareToggleButton.java

@@ -28,10 +28,14 @@ import javax.swing.*;
 
 import com.github.weisj.darklaf.ui.tooltip.DarkTooltipUI;
 import com.github.weisj.darklaf.util.Alignment;
+import com.github.weisj.darklaf.util.LazyValue;
 
 public class TooltipAwareToggleButton extends JToggleButton implements ToolTipAware {
 
-    private ToolTipContext context;
+    private final LazyValue<ToolTipContext> context = new LazyValue<>(() -> new ToolTipContext().setAlignment(Alignment.SOUTH)
+                                                                                                .setCenterAlignment(Alignment.SOUTH)
+                                                                                                .setAlignInside(false)
+                                                                                                .setIgnoreBorder(true));
 
     public TooltipAwareToggleButton() {
         this(null, null);
@@ -62,12 +66,6 @@ public class TooltipAwareToggleButton extends JToggleButton implements ToolTipAw
 
     @Override
     public ToolTipContext getToolTipContext() {
-        if (context == null) {
-            context = new ToolTipContext().setAlignment(Alignment.SOUTH)
-                                          .setCenterAlignment(Alignment.SOUTH)
-                                          .setAlignInside(false)
-                                          .setIgnoreBorder(true);
-        }
-        return context;
+        return context.get();
     }
 }

core/src/main/java/com/github/weisj/darklaf/settings/ThemeSettings.java

@@ -39,22 +39,22 @@ import com.github.weisj.darklaf.theme.event.ThemePreferenceListener;
 import com.github.weisj.darklaf.theme.info.AccentColorRule;
 import com.github.weisj.darklaf.theme.info.FontSizeRule;
 import com.github.weisj.darklaf.util.DarkUIUtil;
+import com.github.weisj.darklaf.util.LazyValue;
 
 public class ThemeSettings implements ThemePreferenceListener {
 
-    private static ThemeSettings instance;
+    private static final LazyValue<ThemeSettings> instance = new LazyValue<>(ThemeSettings::new);
     private final JPanel contentPane;
     private final ThemeSettingsPanel settingsPanel;
     private final ResourceBundle resourceBundle = ResourceBundle.getBundle("theme_settings");
     private JDialog dialog;
 
     public static ThemeSettings getInstance() {
-        if (!isInitialized()) instance = new ThemeSettings();
-        return instance;
+        return instance.get();
     }
 
     public static boolean isInitialized() {
-        return instance != null;
+        return instance.isInitialized();
     }
 
     /**

core/src/main/java/com/github/weisj/darklaf/ui/filechooser/DarkFileChooserUIBridge.java

@@ -172,7 +172,7 @@ public abstract class DarkFileChooserUIBridge extends BasicFileChooserUI {
 
         Locale l = fc.getLocale();
 
-        UIDefaults defaults = MetalUIDefaults.DEFAULTS;
+        UIDefaults defaults = MetalUIDefaults.get();
 
         lookInLabelMnemonic = getMnemonic(defaults, "FileChooser.lookInLabelMnemonic", l);
         lookInLabelText = defaults.getString("FileChooser.lookInLabelText", l);

core/src/main/java/com/github/weisj/darklaf/ui/filechooser/DarkFilePaneUIBridge.java

@@ -457,7 +457,7 @@ public abstract class DarkFilePaneUIBridge extends JPanel implements PropertyCha
         readOnly = UIManager.getBoolean("FileChooser.readOnly");
 
         // TUDU: On windows, get the following localized strings from the OS
-        UIDefaults metal = MetalUIDefaults.DEFAULTS;
+        UIDefaults metal = MetalUIDefaults.get();
 
         viewMenuLabelText = metal.getString("FileChooser.viewMenuLabelText", l);
         refreshActionLabelText = metal.getString("FileChooser.refreshActionLabelText", l);
@@ -600,7 +600,7 @@ public abstract class DarkFilePaneUIBridge extends JPanel implements PropertyCha
                 String title = dataItem.getTitle();
                 if (title != null && title.startsWith("FileChooser.") && title.endsWith("HeaderText")) {
                     // the column must have a string resource that we try to get
-                    String uiTitle = MetalUIDefaults.DEFAULTS.getString(title, table.getLocale());
+                    String uiTitle = MetalUIDefaults.get().getString(title, table.getLocale());
                     if (uiTitle != null) {
                         title = uiTitle;
                     }

core/src/main/java/com/github/weisj/darklaf/ui/filechooser/MetalUIDefaults.java

@@ -27,5 +27,13 @@ package com.github.weisj.darklaf.ui.filechooser;
 import javax.swing.*;
 import javax.swing.plaf.metal.MetalLookAndFeel;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 // Extra class is for lazy initialization
-class MetalUIDefaults { static final UIDefaults DEFAULTS = new MetalLookAndFeel().getDefaults(); }
+class MetalUIDefaults {
+    private static final LazyValue<UIDefaults> DEFAULTS = new LazyValue<>(() -> new MetalLookAndFeel().getDefaults());
+
+    static UIDefaults get() {
+        return DEFAULTS.get();
+    }
+}

property-loader/src/main/java/com/github/weisj/darklaf/icons/IconLoader.java

@@ -35,13 +35,15 @@ import java.util.logging.Logger;
 
 import javax.swing.*;
 
+import com.github.weisj.darklaf.util.LazyValue;
+
 /**
  * @author Jannis Weis
  */
 public final class IconLoader {
     private static final Logger LOGGER = Logger.getLogger(IconLoader.class.getName());
     private static final Map<Class<?>, IconLoader> iconLoaderMap = new HashMap<>();
-    private static IconLoader instance;
+    private static final LazyValue<IconLoader> instance = new LazyValue<>(() -> get(null));
 
     private static Object currentThemeKey;
     private static AwareIconStyle currentAwareStyle;
@@ -63,8 +65,7 @@ public final class IconLoader {
      * @return the default icon loader.
      */
     public static IconLoader get() {
-        if (instance == null) instance = get(null);
-        return instance;
+        return instance.get();
     }
 
     /**

utils/src/main/java/com/github/weisj/darklaf/util/LazyValue.java

@@ -0,0 +1,50 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.util;
+
+import java.util.function.Supplier;
+
+public class LazyValue<T> {
+
+    private Supplier<T> supplier;
+    private T value;
+
+    public LazyValue(final Supplier<T> supplier) {
+
+        this.supplier = supplier;
+    }
+
+    public boolean isInitialized() {
+        return supplier == null;
+    }
+
+    public T get() {
+        if (value == null && supplier != null) {
+            value = supplier.get();
+            supplier = null;
+        }
+        return value;
+    }
+}

utils/src/main/java/com/github/weisj/darklaf/util/PropertyUtil.java

@@ -20,6 +20,7 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
+ *
  */
 package com.github.weisj.darklaf.util;