feat: Add OSGi support

.gitignore

@@ -15,3 +15,5 @@ jdks
 .bach/workspace
 .bach/external-tools
 .bach/external-modules
+bin
+.settings

build.gradle

@@ -1,7 +1,7 @@
 /*
  * SPDX-License-Identifier: Apache-2.0
  *
- * Copyright 2015-2024 Andres Almiray
+ * Copyright 2015-2025 Andres Almiray
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
  */
 plugins {
     id 'com.google.osdetector'
+	id 'biz.aQute.bnd.builder'
 }
 
 ext.javafx_platform = osdetector.os == 'osx' ? 'mac' : osdetector.os == 'windows' ? 'win' : osdetector.os
@@ -78,8 +79,31 @@ idea {
 subprojects { subproj ->
     if (!subproj.name.contains('guide') && !subproj.name.contains('bom')) {
         apply plugin: 'java-library'
+        apply plugin: 'biz.aQute.bnd.builder'  // Apply BND to subprojects
 
+        jar {
+            bundle {
+                bnd '''
+                    Bundle-SymbolicName: ${project.name}
+                    Bundle-Name: ${project.name}
+                    Bundle-Version: ${project.version}
+                    
+                    Import-Package:         !javafx.*, *;
+                    Export-Package:         *;
+                    Bundle-ActivationPolicy: lazy
+                    
+                    # Remove private packages to prevent embedding
+                    Private-Package: !*
+                    
+                    -nouses: true
+                    -noimportjava: true
+                    '''
+            }
+        }
+
         dependencies {
+        	compileOnly 'org.osgi:osgi.core:8.0.0'
+        	compileOnly 'org.osgi:org.osgi.service.component.annotations:1.5.1'
             testImplementation 'junit:junit:4.13.2'
         }
 

core/ikonli-core/src/main/java/module-info.java

@@ -19,6 +19,8 @@
     exports org.kordamp.ikonli;
     requires static org.kordamp.jipsy.annotations;
     requires java.logging;
+    requires static org.osgi.service.component.annotations;
+    requires static osgi.core;
 
     uses org.kordamp.ikonli.IkonHandler;
 

core/ikonli-core/src/main/java/org/kordamp/ikonli/AbstractIkonResolver.java

@@ -17,88 +17,87 @@
  */
 package org.kordamp.ikonli;
 
+import static java.util.Objects.requireNonNull;
+
 import java.util.Arrays;
 import java.util.ServiceLoader;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.logging.Logger;
 
-import static java.util.Objects.requireNonNull;
-
 /**
  * @author Andres Almiray
  */
-public class AbstractIkonResolver {
+public class AbstractIkonResolver implements IkonResolver {
     private static final String ORG_KORDAMP_IKONLI_STRICT = "org.kordamp.ikonli.strict";
     private final static Logger LOGGER = Logger.getLogger(AbstractIkonResolver.class.getName());
 
-    protected boolean registerHandler(IkonHandler handler, Set<IkonHandler> handlers, Set<IkonHandler> customHandlers) {
-        // check whether handler for this font is already loaded via classpath
-        if (isLoadedViaClasspath(handler, handlers)) {
+    protected final Set<IkonHandler> handlers = new CopyOnWriteArraySet<>();
+    protected final Set<IkonHandler> customHandlers = new CopyOnWriteArraySet<>();
+
+    @Override
+    public boolean registerHandler(IkonHandler handler) {
+        requireNonNull(handler, "Handler must not be null");
+        if (isHandlerLoadedViaClasspath(handler)) {
             throwOrWarn(String.format("IkonHandler for %s is already loaded via classpath", handler.getFontFamily()));
             return false;
         }
         return customHandlers.add(handler);
     }
 
-    protected boolean unregisterHandler(IkonHandler handler, Set<IkonHandler> handlers, Set<IkonHandler> customHandlers) {
-        // check whether handler for this font is loaded via classpath
-        if (isLoadedViaClasspath(handler, handlers)) {
+    @Override
+    public boolean unregisterHandler(IkonHandler handler) {
+        requireNonNull(handler, "Handler must not be null");
+        if (isHandlerLoadedViaClasspath(handler)) {
             throwOrWarn(String.format("IkonHandler for %s was loaded via classpath and can't be unregistered", handler.getFontFamily()));
             return false;
         }
         return customHandlers.remove(handler);
     }
 
-    protected IkonHandler resolve(String value, Set<IkonHandler> handlers, Set<IkonHandler> customHandlers) {
+    @Override
+    public IkonHandler resolve(String value) {
         requireNonNull(value, "Ikon description must not be null");
-        for (Set<IkonHandler> hs : Arrays.asList(handlers, customHandlers)) {
-            for (IkonHandler handler : hs) {
-                if (handler.supports(value)) {
-                    return handler;
-                }
-            }
-        }
-        throw new UnsupportedOperationException("Cannot resolve '" + value + "'");
+        return findHandler(value)
+            .orElseThrow(() -> new UnsupportedOperationException("Cannot resolve '" + value + "'"));
     }
 
-    private boolean isLoadedViaClasspath(IkonHandler handler, Set<IkonHandler> handlers) {
-        String fontFamily = handler.getFontFamily();
-        for (IkonHandler classpathHandler : handlers) {
-            if (classpathHandler.getFontFamily().equals(fontFamily)) {
-                return true;
-            }
-        }
-        return false;
+    protected java.util.Optional<IkonHandler> findHandler(String value) {
+        return Arrays.asList(handlers, customHandlers).stream()
+            .flatMap(Set::stream)
+            .filter(handler -> handler.supports(value))
+            .findFirst();
+    }
+
+    private boolean isHandlerLoadedViaClasspath(IkonHandler handler) {
+        return handlers.stream()
+            .anyMatch(h -> h.getFontFamily().equals(handler.getFontFamily()));
     }
 
     private void throwOrWarn(String message) {
-        if (strictChecksEnabled()) {
+        if (Boolean.getBoolean(ORG_KORDAMP_IKONLI_STRICT)) {
             throw new IllegalArgumentException(message);
-        } else {
-            LOGGER.warning(message);
         }
-    }
-
-    private boolean strictChecksEnabled() {
-        return System.getProperty(ORG_KORDAMP_IKONLI_STRICT) == null || Boolean.getBoolean(ORG_KORDAMP_IKONLI_STRICT);
+        LOGGER.warning(message);
     }
 
     public static ServiceLoader<IkonHandler> resolveServiceLoader() {
         // Check if handlers must be loaded from a ModuleLayer
         if (null != IkonHandler.class.getModule().getLayer()) {
-            ServiceLoader<IkonHandler> handlers = ServiceLoader.load(IkonHandler.class.getModule().getLayer(), IkonHandler.class);
-            if (handlers.stream().count() > 0) {
-                return handlers;
+            ServiceLoader<IkonHandler> ikonHandlerServiceLoaders = ServiceLoader.load(
+                IkonHandler.class.getModule().getLayer(), 
+                IkonHandler.class
+            );
+            if (ikonHandlerServiceLoaders.findFirst().isPresent()) {
+                return ikonHandlerServiceLoaders;
             }
         }
 
-        // Check if the IkonHandler.class.classLoader works
-        ServiceLoader<IkonHandler> handlers = ServiceLoader.load(IkonHandler.class, IkonHandler.class.getClassLoader());
-        if (handlers.stream().count() > 0) {
-            return handlers;
-        }
-
-        // If *nothing* else works
-        return ServiceLoader.load(IkonHandler.class);
+        ServiceLoader<IkonHandler> handlers = ServiceLoader.load(
+                IkonHandler.class, 
+                IkonHandler.class.getClassLoader()
+            );
+        // Return if the IkonHandler.class.classLoader works or if *nothing* else works
+        return handlers.findFirst().isPresent() ? handlers : ServiceLoader.load(IkonHandler.class);
     }
 }

core/ikonli-core/src/main/java/org/kordamp/ikonli/DefaultIkonResolver.java

@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2015-2025 Andres Almiray
+ *
+ * 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
+ *
+ *     http://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 org.kordamp.ikonli;
+
+public class DefaultIkonResolver extends AbstractIkonResolver implements IkonResolver {
+    private final FontLoader fontLoader;
+    private static volatile DefaultIkonResolver instance;
+
+    protected DefaultIkonResolver(FontLoader fontLoader) {
+        this.fontLoader = fontLoader;
+        resolveServiceLoader().forEach(handler -> {
+            handlers.add(handler);
+            fontLoader.loadFont(handler);
+        });
+    }
+
+    @Override
+    public boolean registerHandler(IkonHandler handler) {
+        boolean result = super.registerHandler(handler);
+        if (result) {
+            fontLoader.loadFont(handler);
+        }
+        return result;
+    }
+
+    public static IkonResolver getInstance(FontLoader fontLoader) {
+        if (instance == null) {
+            synchronized (DefaultIkonResolver.class) {
+                if (instance == null) {
+                    instance = new DefaultIkonResolver(fontLoader);
+                }
+            }
+        }
+        return instance;
+    }
+}

core/ikonli-core/src/main/java/org/kordamp/ikonli/FontLoader.java

@@ -0,0 +1,24 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2015-2025 Andres Almiray
+ *
+ * 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
+ *
+ *     http://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 org.kordamp.ikonli;
+
+public interface FontLoader {
+
+    void loadFont(IkonHandler handler);
+
+}

core/ikonli-core/src/main/java/org/kordamp/ikonli/IkonResolver.java

@@ -0,0 +1,27 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2015-2025 Andres Almiray
+ *
+ * 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
+ *
+ *     http://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 org.kordamp.ikonli;
+
+public interface IkonResolver {
+
+    IkonHandler resolve(String value);
+
+    boolean registerHandler(IkonHandler handler);
+
+    boolean unregisterHandler(IkonHandler handler);
+}

core/ikonli-core/src/main/java/org/kordamp/ikonli/IkonResolverProvider.java

@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2015-2025 Andres Almiray
+ *
+ * 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
+ *
+ *     http://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 org.kordamp.ikonli;
+
+import org.osgi.framework.Bundle;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.FrameworkUtil;
+import org.osgi.framework.ServiceReference;
+
+public class IkonResolverProvider {
+    private static volatile IkonResolver instance;
+
+    private IkonResolverProvider() {
+    }
+
+    public static IkonResolver getInstance(FontLoader fontLoader) {
+        IkonResolver localInstance = instance;
+        if (localInstance == null) {
+            synchronized (IkonResolverProvider.class) {
+                localInstance = instance;
+                if (localInstance == null) {
+                    instance = localInstance = createIkonResolver(fontLoader);
+                }
+            }
+        }
+        return localInstance;
+    }
+
+    private static IkonResolver createIkonResolver(FontLoader fontLoader) {
+        return tryGetOSGiResolver().orElseGet(() -> DefaultIkonResolver.getInstance(fontLoader));
+    }
+
+    private static java.util.Optional<IkonResolver> tryGetOSGiResolver() {
+        try {
+            if (!isOSGiAvailable()) {
+                return java.util.Optional.empty();
+            }
+
+            Bundle bundle = FrameworkUtil.getBundle(IkonResolverProvider.class);
+            if (bundle == null) {
+                return java.util.Optional.empty();
+            }
+
+            BundleContext context = bundle.getBundleContext();
+            if (context == null) {
+                return java.util.Optional.empty();
+            }
+
+            ServiceReference<IkonResolver> ref = context.getServiceReference(IkonResolver.class);
+            if (ref == null) {
+                return java.util.Optional.empty();
+            }
+
+            IkonResolver resolver = context.getService(ref);
+            return java.util.Optional.ofNullable(resolver);
+
+        } catch (NoClassDefFoundError | IllegalStateException e) {
+            return java.util.Optional.empty();
+        }
+    }
+
+    private static boolean isOSGiAvailable() {
+        try {
+            Class.forName("org.osgi.framework.BundleContext");
+            return true;
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+}