opendaylight/md-sal/sal-dom-api/src/main/java/org/opendaylight/controller/sal/core/api/AbstractConsumer.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 org.osgi.framework.BundleActivator;
  14 import org.osgi.framework.BundleContext;
  15 import org.osgi.framework.ServiceReference;
  16 import org.osgi.util.tracker.ServiceTracker;
  17 import org.osgi.util.tracker.ServiceTrackerCustomizer;
  18
  19 public abstract class AbstractConsumer implements Consumer, BundleActivator,ServiceTrackerCustomizer<Broker, Broker> {
  20
  21
  22
  23
  24     private BundleContext context;
  25     private ServiceTracker<Broker, Broker> tracker;
  26     private Broker broker;
  27
  28     @Override
  29     public final void start(BundleContext context) throws Exception {
  30         this.context = context;
  31         this.startImpl(context);
  32         tracker = new ServiceTracker<>(context, Broker.class, this);
  33         tracker.open();
  34     }
  35
  36
  37
  38     @Override
  39     public final void stop(BundleContext context) throws Exception {
  40         stopImpl(context);
  41         broker = null;
  42         tracker.close();
  43     }
  44
  45     protected void startImpl(BundleContext context) {
  46         // NOOP
  47     }
  48     protected void stopImpl(BundleContext context) {
  49         // NOOP
  50     }
  51
  52     @Override
  53     public Collection<ConsumerFunctionality> getConsumerFunctionality() {
  54         return Collections.emptySet();
  55     }
  56
  57
  58     @Override
  59     public Broker addingService(ServiceReference<Broker> reference) {
  60         if(broker == null) {
  61             broker = context.getService(reference);
  62             broker.registerConsumer(this, context);
  63             return broker;
  64         }
  65
  66         return null;
  67     }
  68
  69     @Override
  70     public void modifiedService(ServiceReference<Broker> reference, Broker service) {
  71         // NOOP
  72     }
  73
  74     @Override
  75     public void removedService(ServiceReference<Broker> reference, Broker service) {
  76         stopImpl(context);
  77     }
  78 }