mdsalutil/mdsalutil-api/src/main/java/org/opendaylight/genius/datastoreutils/AsyncDataTreeChangeListenerBase.java

   1 /*
   2  * Copyright (c) 2016 Ericsson India Global Services Pvt Ltd. 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
   9 package org.opendaylight.genius.datastoreutils;
  10
  11 import com.google.common.base.Preconditions;
  12 import java.util.Collection;
  13 import java.util.concurrent.LinkedBlockingQueue;
  14 import java.util.concurrent.ThreadPoolExecutor;
  15 import java.util.concurrent.TimeUnit;
  16 import javax.annotation.PostConstruct;
  17 import javax.annotation.PreDestroy;
  18 import org.opendaylight.controller.md.sal.binding.api.DataBroker;
  19 import org.opendaylight.controller.md.sal.binding.api.DataObjectModification;
  20 import org.opendaylight.controller.md.sal.binding.api.DataTreeChangeListener;
  21 import org.opendaylight.controller.md.sal.binding.api.DataTreeIdentifier;
  22 import org.opendaylight.controller.md.sal.binding.api.DataTreeModification;
  23 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  24 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  25 import org.opendaylight.yangtools.yang.binding.DataObject;
  26 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
  27 import org.slf4j.Logger;
  28 import org.slf4j.LoggerFactory;
  29
  30 public abstract class AsyncDataTreeChangeListenerBase<T extends DataObject, K extends DataTreeChangeListener>
  31         implements DataTreeChangeListener<T>, AutoCloseable {
  32
  33     private static final Logger LOG = LoggerFactory.getLogger(AsyncDataTreeChangeListenerBase.class);
  34
  35     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_CORE_SIZE = 1;
  36     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_MAX_SIZE = 1;
  37     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_KEEP_ALIVE_TIME_SECS = 300;
  38     private static final int STARTUP_LOOP_TICK = 500;
  39     private static final int STARTUP_LOOP_MAX_RETRIES = 8;
  40
  41     private ListenerRegistration<K> listenerRegistration;
  42
  43     private static ThreadPoolExecutor dataTreeChangeHandlerExecutor = new ThreadPoolExecutor(
  44             DATATREE_CHANGE_HANDLER_THREAD_POOL_CORE_SIZE,
  45             DATATREE_CHANGE_HANDLER_THREAD_POOL_MAX_SIZE,
  46             DATATREE_CHANGE_HANDLER_THREAD_POOL_KEEP_ALIVE_TIME_SECS,
  47             TimeUnit.SECONDS,
  48             new LinkedBlockingQueue<Runnable>());
  49
  50     protected final Class<T> clazz;
  51     private final Class<K> eventClazz;
  52
  53     public AsyncDataTreeChangeListenerBase(Class<T> clazz, Class<K> eventClazz) {
  54         this.clazz = Preconditions.checkNotNull(clazz, "Class can not be null!");
  55         this.eventClazz = Preconditions.checkNotNull(eventClazz, "eventClazz can not be null!");
  56     }
  57
  58     @Override
  59     public void onDataTreeChanged(Collection<DataTreeModification<T>> changes) {
  60         if (changes == null || changes.isEmpty()) {
  61             return;
  62         }
  63
  64         DataTreeChangeHandler dataTreeChangeHandler = new DataTreeChangeHandler(changes);
  65         dataTreeChangeHandlerExecutor.execute(dataTreeChangeHandler);
  66     }
  67
  68     public void registerListener(LogicalDatastoreType dsType, final DataBroker db) {
  69         final DataTreeIdentifier<T> treeId = new DataTreeIdentifier<>(dsType, getWildCardPath());
  70         try {
  71             TaskRetryLooper looper = new TaskRetryLooper(STARTUP_LOOP_TICK, STARTUP_LOOP_MAX_RETRIES);
  72             listenerRegistration = looper.loopUntilNoException(() -> db.registerDataTreeChangeListener(treeId, getDataTreeChangeListener()));
  73         } catch (final Exception e) {
  74             LOG.warn("{}: Data Tree Change listener registration failed.", eventClazz.getName());
  75             LOG.debug("{}: Data Tree Change listener registration failed: {}", eventClazz.getName(), e);
  76             throw new IllegalStateException( eventClazz.getName() + "{}startup failed. System needs restart.", e);
  77         }
  78     }
  79
  80     /**
  81      * Subclasses override this and place initialization logic here, notably
  82      * calls to registerListener(). Note that the overriding method MUST repeat
  83      * the PostConstruct annotation, because JSR 250 specifies that lifecycle
  84      * methods "are called unless a subclass of the declaring class overrides
  85      * the method without repeating the annotation".  (The blueprint-maven-plugin
  86      * would gen. XML which calls PostConstruct annotated methods even if they are
  87      * in a subclass without repeating the annotation, but this is wrong and not
  88      * JSR 250 compliant, and while working in BP, then causes issues e.g. when
  89      * wiring with Guice for tests, so do always repeat it.)
  90      */
  91     @PostConstruct
  92     protected void init() {
  93     }
  94
  95     @Override
  96     @PreDestroy
  97     public void close() throws Exception {
  98         if (listenerRegistration != null) {
  99             try {
 100                 listenerRegistration.close();
 101             } catch (final Exception e) {
 102                 LOG.error("Error when cleaning up DataTreeChangeListener.", e);
 103             }
 104             listenerRegistration = null;
 105         }
 106     }
 107
 108     protected abstract InstanceIdentifier<T> getWildCardPath();
 109     protected abstract void remove(InstanceIdentifier<T> key, T dataObjectModification);
 110     protected abstract void update(InstanceIdentifier<T> key, T dataObjectModificationBefore, T dataObjectModificationAfter);
 111     protected abstract void add(InstanceIdentifier<T> key, T dataObjectModification);
 112     protected abstract K getDataTreeChangeListener();
 113
 114     public class DataTreeChangeHandler implements Runnable {
 115         Collection<DataTreeModification<T>> changes;
 116
 117         public DataTreeChangeHandler(Collection<DataTreeModification<T>> changes) {
 118             this.changes = changes;
 119         }
 120
 121         @Override
 122         public void run() {
 123             for (DataTreeModification<T> change : changes) {
 124                 final InstanceIdentifier<T> key = change.getRootPath().getRootIdentifier();
 125                 final DataObjectModification<T> mod = change.getRootNode();
 126
 127                 switch (mod.getModificationType()) {
 128                     case DELETE:
 129                         remove(key, mod.getDataBefore());
 130                         break;
 131                     case SUBTREE_MODIFIED:
 132                         update(key, mod.getDataBefore(), mod.getDataAfter());
 133                         break;
 134                     case WRITE:
 135                         if (mod.getDataBefore() == null) {
 136                             add(key, mod.getDataAfter());
 137                         } else {
 138                             update(key, mod.getDataBefore(), mod.getDataAfter());
 139                         }
 140                         break;
 141                     default:
 142                         // FIXME: May be not a good idea to throw.
 143                         throw new IllegalArgumentException("Unhandled modification type " + mod.getModificationType());
 144                 }
 145             }
 146         }
 147     }
 148 }