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     // Using non-static Logger so that logs easily identifies actual listener class
  34     private final Logger log = LoggerFactory.getLogger(getClass());
  35
  36     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_CORE_SIZE = 1;
  37     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_MAX_SIZE = 1;
  38     private static final int DATATREE_CHANGE_HANDLER_THREAD_POOL_KEEP_ALIVE_TIME_SECS = 300;
  39     private static final int STARTUP_LOOP_TICK = 500;
  40     private static final int STARTUP_LOOP_MAX_RETRIES = 8;
  41
  42     private ListenerRegistration<K> listenerRegistration;
  43     private final ChainableDataTreeChangeListenerImpl<T> chainingDelegate = new ChainableDataTreeChangeListenerImpl<>();
  44
  45     private static ThreadPoolExecutor dataTreeChangeHandlerExecutor = new ThreadPoolExecutor(
  46             DATATREE_CHANGE_HANDLER_THREAD_POOL_CORE_SIZE,
  47             DATATREE_CHANGE_HANDLER_THREAD_POOL_MAX_SIZE,
  48             DATATREE_CHANGE_HANDLER_THREAD_POOL_KEEP_ALIVE_TIME_SECS,
  49             TimeUnit.SECONDS,
  50             new LinkedBlockingQueue<>());
  51
  52     protected final Class<T> clazz;
  53     private final Class<K> eventClazz;
  54
  55     public AsyncDataTreeChangeListenerBase(Class<T> clazz, Class<K> eventClazz) {
  56         this.clazz = Preconditions.checkNotNull(clazz, "Class can not be null!");
  57         this.eventClazz = Preconditions.checkNotNull(eventClazz, "eventClazz can not be null!");
  58     }
  59
  60     @Override
  61     public void addBeforeListener(DataTreeChangeListener<T> listener) {
  62         chainingDelegate.addBeforeListener(listener);
  63     }
  64
  65     @Override
  66     public void addAfterListener(DataTreeChangeListener<T> listener) {
  67         chainingDelegate.addAfterListener(listener);
  68     }
  69
  70     @Override
  71     public void onDataTreeChanged(Collection<DataTreeModification<T>> changes) {
  72         if (changes == null || changes.isEmpty()) {
  73             return;
  74         }
  75
  76         DataTreeChangeHandler dataTreeChangeHandler = new DataTreeChangeHandler(changes);
  77         dataTreeChangeHandlerExecutor.execute(dataTreeChangeHandler);
  78     }
  79
  80     public void registerListener(LogicalDatastoreType dsType, final DataBroker db) {
  81         final DataTreeIdentifier<T> treeId = new DataTreeIdentifier<>(dsType, getWildCardPath());
  82         try {
  83             TaskRetryLooper looper = new TaskRetryLooper(STARTUP_LOOP_TICK, STARTUP_LOOP_MAX_RETRIES);
  84             listenerRegistration = looper.loopUntilNoException(() -> db.registerDataTreeChangeListener(treeId, getDataTreeChangeListener()));
  85         } catch (final Exception e) {
  86             log.warn("{}: Data Tree Change listener registration failed.", eventClazz.getName());
  87             log.debug("{}: Data Tree Change listener registration failed: {}", eventClazz.getName(), e);
  88             throw new IllegalStateException( eventClazz.getName() + "{}startup failed. System needs restart.", e);
  89         }
  90     }
  91
  92     /**
  93      * Subclasses override this and place initialization logic here, notably
  94      * calls to registerListener(). Note that the overriding method MUST repeat
  95      * the PostConstruct annotation, because JSR 250 specifies that lifecycle
  96      * methods "are called unless a subclass of the declaring class overrides
  97      * the method without repeating the annotation".  (The blueprint-maven-plugin
  98      * would gen. XML which calls PostConstruct annotated methods even if they are
  99      * in a subclass without repeating the annotation, but this is wrong and not
 100      * JSR 250 compliant, and while working in BP, then causes issues e.g. when
 101      * wiring with Guice for tests, so do always repeat it.)
 102      */
 103     @PostConstruct
 104     protected void init() {
 105     }
 106
 107     @Override
 108     @PreDestroy
 109     public void close() throws Exception {
 110         if (listenerRegistration != null) {
 111             try {
 112                 listenerRegistration.close();
 113             } catch (final Exception e) {
 114                 log.error("Error when cleaning up DataTreeChangeListener.", e);
 115             }
 116             listenerRegistration = null;
 117         }
 118     }
 119
 120     protected abstract InstanceIdentifier<T> getWildCardPath();
 121     protected abstract void remove(InstanceIdentifier<T> key, T dataObjectModification);
 122     protected abstract void update(InstanceIdentifier<T> key, T dataObjectModificationBefore, T dataObjectModificationAfter);
 123     protected abstract void add(InstanceIdentifier<T> key, T dataObjectModification);
 124     protected abstract K getDataTreeChangeListener();
 125
 126     public class DataTreeChangeHandler implements Runnable {
 127         private final Collection<DataTreeModification<T>> changes;
 128
 129         public DataTreeChangeHandler(Collection<DataTreeModification<T>> changes) {
 130             chainingDelegate.notifyBeforeOnDataTreeChanged(changes);
 131             this.changes = changes;
 132             for (DataTreeModification<T> change : changes) {
 133                 log.debug("sync run() {}", change);
 134             }
 135         }
 136
 137         @Override
 138         public void run() {
 139             for (DataTreeModification<T> change : changes) {
 140                 final InstanceIdentifier<T> key = change.getRootPath().getRootIdentifier();
 141                 final DataObjectModification<T> mod = change.getRootNode();
 142
 143                 switch (mod.getModificationType()) {
 144                     case DELETE:
 145                         remove(key, mod.getDataBefore());
 146                         break;
 147                     case SUBTREE_MODIFIED:
 148                         update(key, mod.getDataBefore(), mod.getDataAfter());
 149                         break;
 150                     case WRITE:
 151                         if (mod.getDataBefore() == null) {
 152                             add(key, mod.getDataAfter());
 153                         } else {
 154                             update(key, mod.getDataBefore(), mod.getDataAfter());
 155                         }
 156                         break;
 157                     default:
 158                         // FIXME: May be not a good idea to throw.
 159                         throw new IllegalArgumentException("Unhandled modification type " + mod.getModificationType());
 160                 }
 161                 log.debug("async run() {}", change);
 162             }
 163             chainingDelegate.notifyAfterOnDataTreeChanged(changes);
 164         }
 165     }
 166 }