opendaylight/md-sal/sal-dom-api/src/main/java/org/opendaylight/controller/sal/core/api/AbstractProvider.java

   1 /*
   2  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.sal.core.api;
   9
  10 import java.util.Collection;
  11 import java.util.Collections;
  12
  13 import javax.naming.Context;
  14
  15 import org.opendaylight.controller.sal.core.api.Broker.ProviderSession;
  16 import org.osgi.framework.BundleActivator;
  17 import org.osgi.framework.BundleContext;
  18 import org.osgi.framework.ServiceReference;
  19 import org.osgi.util.tracker.ServiceTracker;
  20 import org.osgi.util.tracker.ServiceTrackerCustomizer;
  21
  22 public abstract class AbstractProvider implements BundleActivator, Provider,ServiceTrackerCustomizer<Broker, Broker> {
  23
  24     private Broker broker;
  25     private BundleContext context;
  26     private ServiceTracker<Broker, Broker> tracker;
  27     @Override
  28     public Collection<ProviderFunctionality> getProviderFunctionality() {
  29         return Collections.emptySet();
  30     }
  31
  32     @Override
  33     public final void start(BundleContext context) throws Exception {
  34         this.context = context;
  35         this.startImpl(context);
  36         tracker = new ServiceTracker<>(context, Broker.class, this);
  37         tracker.open();
  38     }
  39
  40     protected void startImpl(BundleContext context) {
  41         // NOOP
  42     }
  43     protected void stopImpl(BundleContext context) {
  44         // NOOP
  45     }
  46
  47     @Override
  48     public final void stop(BundleContext context) throws Exception {
  49         broker = null;
  50         tracker.close();
  51         tracker = null;
  52         stopImpl(context);
  53     }
  54
  55     @Override
  56     public Broker addingService(ServiceReference<Broker> reference) {
  57         if(broker == null) {
  58             broker = context.getService(reference);
  59             broker.registerProvider(this, context);
  60             return broker;
  61         }
  62
  63         return null;
  64     }
  65
  66     @Override
  67     public void modifiedService(ServiceReference<Broker> reference, Broker service) {
  68         // NOOP
  69     }
  70
  71     @Override
  72     public void removedService(ServiceReference<Broker> reference, Broker service) {
  73         stopImpl(context);
  74     }
  75
  76 }