yang/yang-repo-spi/src/main/java/org/opendaylight/yangtools/yang/model/repo/spi/AbstractSchemaRepository.java

   1 /*
   2  * Copyright (c) 2014 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.yangtools.yang.model.repo.spi;
   9
  10 import static org.opendaylight.yangtools.util.concurrent.FluentFutures.immediateFailedFluentFuture;
  11
  12 import com.google.common.annotations.Beta;
  13 import com.google.common.collect.ArrayListMultimap;
  14 import com.google.common.collect.ListMultimap;
  15 import com.google.common.util.concurrent.FutureCallback;
  16 import com.google.common.util.concurrent.Futures;
  17 import com.google.common.util.concurrent.ListenableFuture;
  18 import com.google.common.util.concurrent.MoreExecutors;
  19 import java.io.Serializable;
  20 import java.util.ArrayList;
  21 import java.util.Collections;
  22 import java.util.Comparator;
  23 import java.util.HashMap;
  24 import java.util.Iterator;
  25 import java.util.List;
  26 import java.util.Map;
  27 import org.checkerframework.checker.lock.qual.GuardedBy;
  28 import org.opendaylight.yangtools.concepts.AbstractObjectRegistration;
  29 import org.opendaylight.yangtools.concepts.Registration;
  30 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  31 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  32 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  33 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36
  37 /**
  38  * Abstract base class for {@link SchemaRepository} implementations. It handles registration and lookup of schema
  39  * sources, subclasses need only to provide their own {@link #createEffectiveModelContextFactory()} implementation.
  40  */
  41 @Beta
  42 public abstract class AbstractSchemaRepository implements SchemaRepository, SchemaSourceRegistry {
  43     private static final Logger LOG = LoggerFactory.getLogger(AbstractSchemaRepository.class);
  44
  45     /*
  46      * Source identifier -> representation -> provider map. We usually are looking for
  47      * a specific representation of a source.
  48      */
  49     @GuardedBy("this")
  50     private final Map<SourceIdentifier, ListMultimap<Class<? extends SchemaSourceRepresentation>,
  51             AbstractSchemaSourceRegistration<?>>> sources = new HashMap<>();
  52
  53     /*
  54      * Schema source listeners.
  55      */
  56     @GuardedBy("this")
  57     private final List<SchemaListenerRegistration> listeners = new ArrayList<>();
  58
  59     @SuppressWarnings("unchecked")
  60     private static <T extends SchemaSourceRepresentation> ListenableFuture<T> fetchSource(
  61             final SourceIdentifier id, final Iterator<AbstractSchemaSourceRegistration<?>> it) {
  62         final AbstractSchemaSourceRegistration<?> reg = it.next();
  63
  64         return Futures.catchingAsync(((SchemaSourceProvider<T>)reg.getProvider()).getSource(id), Throwable.class,
  65             input -> {
  66                 LOG.debug("Failed to acquire source from {}", reg, input);
  67
  68                 if (it.hasNext()) {
  69                     return fetchSource(id, it);
  70                 }
  71
  72                 throw new MissingSchemaSourceException("All available providers exhausted", id, input);
  73             }, MoreExecutors.directExecutor());
  74     }
  75
  76     @Override
  77     public <T extends SchemaSourceRepresentation> ListenableFuture<T> getSchemaSource(final SourceIdentifier id,
  78             final Class<T> representation) {
  79         final ArrayList<AbstractSchemaSourceRegistration<?>> sortedSchemaSourceRegistrations;
  80
  81         synchronized (this) {
  82             final var srcs = sources.get(id);
  83             if (srcs == null) {
  84                 return immediateFailedFluentFuture(new MissingSchemaSourceException(
  85                     "No providers registered for source " + id, id));
  86             }
  87
  88             sortedSchemaSourceRegistrations = new ArrayList<>(srcs.get(representation));
  89         }
  90
  91         // TODO, remove and make sources keep sorted multimap (e.g. ArrayListMultimap with SortedLists)
  92         sortedSchemaSourceRegistrations.sort(SchemaProviderCostComparator.INSTANCE);
  93
  94         final var regs = sortedSchemaSourceRegistrations.iterator();
  95         if (!regs.hasNext()) {
  96             return immediateFailedFluentFuture(new MissingSchemaSourceException(
  97                         "No providers for source " + id + " representation " + representation + " available", id));
  98         }
  99
 100         final ListenableFuture<T> fetchSourceFuture = fetchSource(id, regs);
 101         // Add callback to notify cache listeners about encountered schema
 102         Futures.addCallback(fetchSourceFuture, new FutureCallback<T>() {
 103             @Override
 104             public void onSuccess(final T result) {
 105                 for (var listener : listeners) {
 106                     listener.getInstance().schemaSourceEncountered(result);
 107                 }
 108             }
 109
 110             @Override
 111             @SuppressWarnings("checkstyle:parameterName")
 112             public void onFailure(final Throwable t) {
 113                 LOG.trace("Skipping notification for encountered source {}, fetching source failed", id, t);
 114             }
 115         }, MoreExecutors.directExecutor());
 116
 117         return fetchSourceFuture;
 118     }
 119
 120     private synchronized <T extends SchemaSourceRepresentation> void addSource(final PotentialSchemaSource<T> source,
 121             final AbstractSchemaSourceRegistration<T> reg) {
 122         sources.computeIfAbsent(source.getSourceIdentifier(), ignored -> ArrayListMultimap.create())
 123             .put(source.getRepresentation(), reg);
 124
 125         final var reps = Collections.<PotentialSchemaSource<?>>singleton(source);
 126         for (var l : listeners) {
 127             l.getInstance().schemaSourceRegistered(reps);
 128         }
 129     }
 130
 131     private synchronized <T extends SchemaSourceRepresentation> void removeSource(final PotentialSchemaSource<?> source,
 132             final SchemaSourceRegistration<?> reg) {
 133         final var m = sources.get(source.getSourceIdentifier());
 134         if (m != null) {
 135             m.remove(source.getRepresentation(), reg);
 136
 137             for (var l : listeners) {
 138                 l.getInstance().schemaSourceUnregistered(source);
 139             }
 140
 141             if (m.isEmpty()) {
 142                 sources.remove(source.getSourceIdentifier());
 143             }
 144         }
 145     }
 146
 147     @Override
 148     public <T extends SchemaSourceRepresentation> SchemaSourceRegistration<T> registerSchemaSource(
 149             final SchemaSourceProvider<? super T> provider, final PotentialSchemaSource<T> source) {
 150         final var src = source.cachedReference();
 151         final var ret = new AbstractSchemaSourceRegistration<>(provider, src) {
 152             @Override
 153             protected void removeRegistration() {
 154                 removeSource(src, this);
 155             }
 156         };
 157
 158         addSource(src, ret);
 159         return ret;
 160     }
 161
 162     @Override
 163     public Registration registerSchemaSourceListener(final SchemaSourceListener listener) {
 164         final SchemaListenerRegistration ret = new SchemaListenerRegistration(listener);
 165
 166         synchronized (this) {
 167             final var col = new ArrayList<PotentialSchemaSource<?>>();
 168             for (var m : sources.values()) {
 169                 for (var r : m.values()) {
 170                     col.add(r.getInstance());
 171                 }
 172             }
 173
 174             // Notify first, so translator-type listeners, who react by registering a source
 175             // do not cause infinite loop.
 176             listener.schemaSourceRegistered(col);
 177             listeners.add(ret);
 178         }
 179         return ret;
 180     }
 181
 182     private final class SchemaListenerRegistration extends AbstractObjectRegistration<SchemaSourceListener> {
 183         SchemaListenerRegistration(final SchemaSourceListener instance) {
 184             super(instance);
 185         }
 186
 187         @Override
 188         protected void removeRegistration() {
 189             listeners.remove(this);
 190         }
 191     }
 192
 193     private static final class SchemaProviderCostComparator implements Comparator<AbstractSchemaSourceRegistration<?>>,
 194             Serializable {
 195         static final SchemaProviderCostComparator INSTANCE = new SchemaProviderCostComparator();
 196
 197         @java.io.Serial
 198         private static final long serialVersionUID = 1L;
 199
 200         @Override
 201         public int compare(final AbstractSchemaSourceRegistration<?> o1, final AbstractSchemaSourceRegistration<?> o2) {
 202             return o1.getInstance().getCost() - o2.getInstance().getCost();
 203         }
 204
 205         @java.io.Serial
 206         private Object readResolve() {
 207             return INSTANCE;
 208         }
 209     }
 210 }