1 files changed, 62 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/extensibility/SingletonExtensionFactory.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/extensibility/SingletonExtensionFactory.java
new file mode 100644
index 00000000..29705968
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/extensibility/SingletonExtensionFactory.java
@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2014, Zoltan Ujhelyi, Istvan Rath and Daniel Varro
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-v20.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package tools.refinery.viatra.runtime.extensibility;
+
+import java.lang.reflect.Method;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IExecutableExtension;
+import org.eclipse.core.runtime.IExecutableExtensionFactory;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+import org.osgi.framework.Bundle;
+
+/**
+ * Factory to register a static singleton instance in an extension point. 
+ * 
+ * @author Zoltan Ujhelyi
+ * 
+ */
+public class SingletonExtensionFactory implements IExecutableExtension, IExecutableExtensionFactory {
+
+    private String clazzName;
+    private Bundle bundle;
+
+    protected Bundle getBundle() {
+        return bundle;
+    }
+    
+    @Override
+    public Object create() throws CoreException {
+        try {
+            final Class<?> clazz = bundle.loadClass(clazzName);
+            Method method = clazz.getMethod("instance");
+            return method.invoke(null);
+        } catch (Exception e) {
+            throw new CoreException(new Status(IStatus.ERROR, bundle.getSymbolicName(), "Error loading group "
+                    + clazzName, e));
+        }
+    }
+
+    @Override
+    public void setInitializationData(IConfigurationElement config, String propertyName, Object data)
+            throws CoreException {
+        String id = config.getContributor().getName();
+        bundle = Platform.getBundle(id);
+        if (data instanceof String) {
+            clazzName = (String) data;
+        } else {
+            throw new CoreException(new Status(IStatus.ERROR, bundle.getSymbolicName(),
+                    "Unsupported extension initialization data: " + data));
+        }
+    }
+
+}