[KARAF-7437] Improve DOSGi exported interface property parsing

Match with OSGI R7 specs section 100.2

Author: CMoH

dosgi/src/main/java/org/apache/karaf/cellar/dosgi/Constants.java

@@ -28,4 +28,5 @@ public abstract class Constants {
     public static final String EXPORTED_INTERFACES = "service.exported.interfaces";
     public static final String ENDPOINT_FRAMEWORK_UUID = "frameworkUUID";
 
+    public static final String[] NO_EXPORTED_INTERFACES = {};
 }

dosgi/src/main/java/org/apache/karaf/cellar/dosgi/ExportServiceListener.java

@@ -26,6 +26,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -111,10 +112,9 @@ public void exportService(ServiceReference serviceReference) {
         try {
             Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
 
-            String exportedServices = (String) serviceReference.getProperty(Constants.EXPORTED_INTERFACES);
-            if (exportedServices != null && exportedServices.length() > 0) {
-                LOGGER.debug("CELLAR DOSGI: registering services {} in the cluster", exportedServices);
-                String[] interfaces = exportedServices.split(Constants.INTERFACE_SEPARATOR);
+            String[] interfaces = getExportedInterfaces(serviceReference);
+            if (interfaces.length > 0) {
+                LOGGER.debug("CELLAR DOSGI: registering services {} in the cluster", (Object) interfaces);
                 Object service = bundleContext.getService(serviceReference);
 
                 Set<String> exportedInterfaces = getServiceInterfaces(service, interfaces);
@@ -159,10 +159,9 @@ public void unExportService(ServiceReference serviceReference) {
         ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader();
         try {
             Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
-            String exportedServices = (String) serviceReference.getProperty(Constants.EXPORTED_INTERFACES);
-            if (exportedServices != null && exportedServices.length() > 0) {
-                LOGGER.debug("CELLAR DOSGI: un-register service {} from the cluster", exportedServices);
-                String[] interfaces = exportedServices.split(Constants.INTERFACE_SEPARATOR);
+            String[] interfaces = getExportedInterfaces(serviceReference);
+            if (interfaces.length > 0) {
+                LOGGER.debug("CELLAR DOSGI: un-register service {} from the cluster", (Object) interfaces);
                 Object service = bundleContext.getService(serviceReference);
 
                 Set<String> exportedInterfaces = getServiceInterfaces(service, interfaces);
@@ -188,6 +187,21 @@ public void unExportService(ServiceReference serviceReference) {
         }
     }
 
+
+    private String[] getExportedInterfaces(ServiceReference serviceReference) {
+        Object property = serviceReference.getProperty(Constants.EXPORTED_INTERFACES);
+        if (property != null) {
+            if (property instanceof String)
+                return ((String) property).split(Constants.INTERFACE_SEPARATOR);
+            if (property instanceof String[])
+                return (String[]) property;
+            if (property instanceof Collection)
+                return (String[])((Collection) property).toArray();
+            LOGGER.warn("CELLAR DOSGI: Illegal value type on property {} on service reference {}", Constants.EXPORTED_INTERFACES, serviceReference);
+        }
+        return Constants.NO_EXPORTED_INTERFACES;
+    }
+
     /**
      * Get the interfaces that match the exported service interfaces.
      *