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<T>>
  31         implements DataTreeChangeListener<T>, ChainableDataTreeChangeListener<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     private final ChainableDataTreeChangeListenerImpl<T> chainingDelegate = new ChainableDataTreeChangeListenerImpl<>();
  43
  44     private static ThreadPoolExecutor dataTreeChangeHandlerExecutor = new ThreadPoolExecutor(
  45             DATATREE_CHANGE_HANDLER_THREAD_POOL_CORE_SIZE,
  46             DATATREE_CHANGE_HANDLER_THREAD_POOL_MAX_SIZE,
  47             DATATREE_CHANGE_HANDLER_THREAD_POOL_KEEP_ALIVE_TIME_SECS,
  48             TimeUnit.SECONDS,
  49             new LinkedBlockingQueue<>());
  50
  51     protected final Class<T> clazz;
  52     private final Class<K> eventClazz;
  53
  54     public AsyncDataTreeChangeListenerBase(Class<T> clazz, Class<K> eventClazz) {
  55         this.clazz = Preconditions.checkNotNull(clazz, "Class can not be null!");
  56         this.eventClazz = Preconditions.checkNotNull(eventClazz, "eventClazz can not be null!");
  57     }
  58
  59     @Override
  60     public void addAfterListener(DataTreeChangeListener<T> listener) {
  61         chainingDelegate.addAfterListener(listener);
  62     }
  63
  64     @Override
  65     public void onDataTreeChanged(Collection<DataTreeModification<T>> changes) {
  66         if (changes == null || changes.isEmpty()) {
  67             return;
  68         }
  69
  70         DataTreeChangeHandler dataTreeChangeHandler = new DataTreeChangeHandler(changes);
  71         dataTreeChangeHandlerExecutor.execute(dataTreeChangeHandler);
  72     }
  73
  74     public void registerListener(LogicalDatastoreType dsType, final DataBroker db) {
  75         final DataTreeIdentifier<T> treeId = new DataTreeIdentifier<>(dsType, getWildCardPath());
  76         try {
  77             TaskRetryLooper looper = new TaskRetryLooper(STARTUP_LOOP_TICK, STARTUP_LOOP_MAX_RETRIES);
  78             listenerRegistration = looper.loopUntilNoException(() -> db.registerDataTreeChangeListener(treeId, getDataTreeChangeListener()));
  79         } catch (final Exception e) {
  80             LOG.warn("{}: Data Tree Change listener registration failed.", eventClazz.getName());
  81             LOG.debug("{}: Data Tree Change listener registration failed: {}", eventClazz.getName(), e);
  82             throw new IllegalStateException( eventClazz.getName() + "{}startup failed. System needs restart.", e);
  83         }
  84     }
  85
  86     /**
  87      * Subclasses override this and place initialization logic here, notably
  88      * calls to registerListener(). Note that the overriding method MUST repeat
  89      * the PostConstruct annotation, because JSR 250 specifies that lifecycle
  90      * methods "are called unless a subclass of the declaring class overrides
  91      * the method without repeating the annotation".  (The blueprint-maven-plugin
  92      * would gen. XML which calls PostConstruct annotated methods even if they are
  93      * in a subclass without repeating the annotation, but this is wrong and not
  94      * JSR 250 compliant, and while working in BP, then causes issues e.g. when
  95      * wiring with Guice for tests, so do always repeat it.)
  96      */
  97     @PostConstruct
  98     protected void init() {
  99     }
 100
 101     @Override
 102     @PreDestroy
 103     public void close() throws Exception {
 104         if (listenerRegistration != null) {
 105             try {
 106                 listenerRegistration.close();
 107             } catch (final Exception e) {
 108                 LOG.error("Error when cleaning up DataTreeChangeListener.", e);
 109             }
 110             listenerRegistration = null;
 111         }
 112     }
 113
 114     protected abstract InstanceIdentifier<T> getWildCardPath();
 115     protected abstract void remove(InstanceIdentifier<T> key, T dataObjectModification);
 116     protected abstract void update(InstanceIdentifier<T> key, T dataObjectModificationBefore, T dataObjectModificationAfter);
 117     protected abstract void add(InstanceIdentifier<T> key, T dataObjectModification);
 118     protected abstract K getDataTreeChangeListener();
 119
 120     public class DataTreeChangeHandler implements Runnable {
 121         private final Collection<DataTreeModification<T>> changes;
 122
 123         public DataTreeChangeHandler(Collection<DataTreeModification<T>> changes) {
 124             this.changes = changes;
 125         }
 126
 127         @Override
 128         public void run() {
 129             for (DataTreeModification<T> change : changes) {
 130                 final InstanceIdentifier<T> key = change.getRootPath().getRootIdentifier();
 131                 final DataObjectModification<T> mod = change.getRootNode();
 132
 133                 switch (mod.getModificationType()) {
 134                     case DELETE:
 135                         remove(key, mod.getDataBefore());
 136                         break;
 137                     case SUBTREE_MODIFIED:
 138                         update(key, mod.getDataBefore(), mod.getDataAfter());
 139                         break;
 140                     case WRITE:
 141                         if (mod.getDataBefore() == null) {
 142                             add(key, mod.getDataAfter());
 143                         } else {
 144                             update(key, mod.getDataBefore(), mod.getDataAfter());
 145                         }
 146                         break;
 147                     default:
 148                         // FIXME: May be not a good idea to throw.
 149                         throw new IllegalArgumentException("Unhandled modification type " + mod.getModificationType());
 150                 }
 151             }
 152             chainingDelegate.notifyAfterOnDataTreeChanged(changes);
 153         }
 154     }
 155 }