[AMQ-5821] Use wiring to check for extensions

This closes #119

activemq-broker/src/main/java/org/apache/activemq/util/osgi/Activator.java

@@ -16,14 +16,18 @@
  */
 package org.apache.activemq.util.osgi;
 
+import static org.osgi.framework.wiring.BundleRevision.PACKAGE_NAMESPACE;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Properties;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
@@ -38,6 +42,9 @@ import org.osgi.framework.BundleActivator;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.BundleEvent;
 import org.osgi.framework.SynchronousBundleListener;
+import org.osgi.framework.wiring.BundleCapability;
+import org.osgi.framework.wiring.BundleWire;
+import org.osgi.framework.wiring.BundleWiring;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -50,9 +57,10 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
 
     private static final Logger LOG = LoggerFactory.getLogger(Activator.class);
 
-    private final ConcurrentMap<String, Class> serviceCache = new ConcurrentHashMap<String, Class>();
+    private final ConcurrentMap<String, Class<?>> serviceCache = new ConcurrentHashMap<String, Class<?>>();
     private final ConcurrentMap<Long, BundleWrapper> bundleWrappers = new ConcurrentHashMap<Long, BundleWrapper>();
     private BundleContext bundleContext;
+    private Set<BundleCapability> packageCapabilities = new HashSet<BundleCapability>();
 
     // ================================================================
     // BundleActivator interface impl
@@ -67,6 +75,9 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
 
         debug("activating");
         this.bundleContext = bundleContext;
+        
+        cachePackageCapabilities(Service.class, Transport.class, DiscoveryAgent.class, PersistenceAdapter.class);
+        
         debug("checking existing bundles");
         bundleContext.addBundleListener(this);
         for (Bundle bundle : bundleContext.getBundles()) {
@@ -78,6 +89,27 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
         debug("activated");
     }
 
+    /**
+     * Caches the package capabilities that are needed for a set of interface classes
+     *  
+     * @param classes interfaces we want to track
+     */
+    private void cachePackageCapabilities(Class<?> ... classes) {
+        BundleWiring ourWiring = bundleContext.getBundle().adapt(BundleWiring.class);
+        Set<String> packageNames = new HashSet<String>();
+        for (Class<?> clazz: classes) {
+            packageNames.add(clazz.getPackage().getName());
+        }
+        
+        List<BundleCapability> ourExports = ourWiring.getCapabilities(PACKAGE_NAMESPACE);
+        for (BundleCapability ourExport : ourExports) {
+            String ourPkgName = (String) ourExport.getAttributes().get(PACKAGE_NAMESPACE);
+            if (packageNames.contains(ourPkgName)) {
+                packageCapabilities.add(ourExport);
+            }
+        }
+    }
+
 
     @Override
     public synchronized void stop(BundleContext bundleContext) throws Exception {
@@ -105,12 +137,15 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
 
     protected void register(final Bundle bundle) {
         debug("checking bundle " + bundle.getBundleId());
-        if( !isImportingUs(bundle) ) {
-            debug("The bundle does not import us: "+ bundle.getBundleId());
-            return;
-        }
+        if (isOurBundle(bundle) || isImportingUs(bundle) ) {
+            debug("Registering bundle for extension resolution: "+ bundle.getBundleId());
             bundleWrappers.put(bundle.getBundleId(), new BundleWrapper(bundle));
         }
+    }
+
+    private boolean isOurBundle(final Bundle bundle) {
+        return bundle.getBundleId() == bundleContext.getBundle().getBundleId();
+    }
 
     /**
      * When bundles unload.. we remove them thier cached Class entries from the
@@ -137,7 +172,7 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
 
     @Override
     public Object create(String path) throws IllegalAccessException, InstantiationException, IOException, ClassNotFoundException {
-        Class clazz = serviceCache.get(path);
+        Class<?> clazz = serviceCache.get(path);
         if (clazz == null) {
             StringBuffer warnings = new StringBuffer();
             // We need to look for a bundle that has that class.
@@ -205,20 +240,23 @@ public class Activator implements BundleActivator, SynchronousBundleListener, Ob
         }
     }
 
+    /**
+     * We consider a bundle to be a candidate for objects if it imports at least
+     * one of the packages of our interfaces
+     * 
+     * @param bundle
+     * @return
+     */
     private boolean isImportingUs(Bundle bundle) {
-        return isImportingClass(bundle, Service.class)
-                || isImportingClass(bundle, Transport.class)
-                || isImportingClass(bundle, DiscoveryAgent.class)
-                || isImportingClass(bundle, PersistenceAdapter.class);
+        BundleWiring wiring = bundle.adapt(BundleWiring.class);
+        List<BundleWire> imports = wiring.getRequiredWires(PACKAGE_NAMESPACE);
+        for (BundleWire importWire : imports) {
+            if (packageCapabilities.contains(importWire.getCapability())) {
+                return true;
+            }
         }
-
-    private boolean isImportingClass(Bundle bundle, Class clazz) {
-        try {
-            return bundle.loadClass(clazz.getName())==clazz;
-        } catch (ClassNotFoundException e) {
         return false;
     }
-    }
 
     private static class BundleWrapper {
         private final Bundle bundle;