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.collect.Lists;
  16 import com.google.common.collect.Multimap;
  17 import com.google.common.util.concurrent.FutureCallback;
  18 import com.google.common.util.concurrent.Futures;
  19 import com.google.common.util.concurrent.ListenableFuture;
  20 import com.google.common.util.concurrent.MoreExecutors;
  21 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  22 import java.io.Serializable;
  23 import java.util.ArrayList;
  24 import java.util.Collection;
  25 import java.util.Collections;
  26 import java.util.Comparator;
  27 import java.util.HashMap;
  28 import java.util.Iterator;
  29 import java.util.List;
  30 import java.util.Map;
  31 import org.checkerframework.checker.lock.qual.GuardedBy;
  32 import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
  33 import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
  34 import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
  35 import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
  36 import org.slf4j.Logger;
  37 import org.slf4j.LoggerFactory;
  38
  39 /**
  40  * Abstract base class for {@link SchemaRepository} implementations. It handles registration and lookup of schema
  41  * sources, subclasses need only to provide their own {@link #createEffectiveModelContextFactory()} implementation.
  42  */
  43 @Beta
  44 public abstract class AbstractSchemaRepository implements SchemaRepository, SchemaSourceRegistry {
  45     private static final Logger LOG = LoggerFactory.getLogger(AbstractSchemaRepository.class);
  46
  47     /*
  48      * Source identifier -> representation -> provider map. We usually are looking for
  49      * a specific representation of a source.
  50      */
  51     @GuardedBy("this")
  52     private final Map<SourceIdentifier, ListMultimap<Class<? extends SchemaSourceRepresentation>,
  53             AbstractSchemaSourceRegistration<?>>> sources = new HashMap<>();
  54
  55     /*
  56      * Schema source listeners.
  57      */
  58     @GuardedBy("this")
  59     private final List<SchemaListenerRegistration> listeners = new ArrayList<>();
  60
  61     @SuppressWarnings("unchecked")
  62     private static <T extends SchemaSourceRepresentation> ListenableFuture<T> fetchSource(
  63             final SourceIdentifier id, final Iterator<AbstractSchemaSourceRegistration<?>> it) {
  64         final AbstractSchemaSourceRegistration<?> reg = it.next();
  65
  66         return Futures.catchingAsync(((SchemaSourceProvider<T>)reg.getProvider()).getSource(id), Throwable.class,
  67             input -> {
  68                 LOG.debug("Failed to acquire source from {}", reg, input);
  69
  70                 if (it.hasNext()) {
  71                     return fetchSource(id, it);
  72                 }
  73
  74                 throw new MissingSchemaSourceException("All available providers exhausted", id, input);
  75             }, MoreExecutors.directExecutor());
  76     }
  77
  78     @Override
  79     public <T extends SchemaSourceRepresentation> ListenableFuture<T> getSchemaSource(final SourceIdentifier id,
  80             final Class<T> representation) {
  81         final ArrayList<AbstractSchemaSourceRegistration<?>> sortedSchemaSourceRegistrations;
  82
  83         synchronized (this) {
  84             final ListMultimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> srcs =
  85                 sources.get(id);
  86             if (srcs == null) {
  87                 return immediateFailedFluentFuture(new MissingSchemaSourceException(
  88                     "No providers registered for source " + id, id));
  89             }
  90
  91             sortedSchemaSourceRegistrations = Lists.newArrayList(srcs.get(representation));
  92         }
  93
  94         // TODO, remove and make sources keep sorted multimap (e.g. ArrayListMultimap with SortedLists)
  95         sortedSchemaSourceRegistrations.sort(SchemaProviderCostComparator.INSTANCE);
  96
  97         final Iterator<AbstractSchemaSourceRegistration<?>> regs = sortedSchemaSourceRegistrations.iterator();
  98         if (!regs.hasNext()) {
  99             return immediateFailedFluentFuture(new MissingSchemaSourceException(
 100                         "No providers for source " + id + " representation " + representation + " available", id));
 101         }
 102
 103         final ListenableFuture<T> fetchSourceFuture = fetchSource(id, regs);
 104         // Add callback to notify cache listeners about encountered schema
 105         Futures.addCallback(fetchSourceFuture, new FutureCallback<T>() {
 106             @Override
 107             public void onSuccess(final T result) {
 108                 for (final SchemaListenerRegistration listener : listeners) {
 109                     listener.getInstance().schemaSourceEncountered(result);
 110                 }
 111             }
 112
 113             @Override
 114             @SuppressWarnings("checkstyle:parameterName")
 115             public void onFailure(final Throwable t) {
 116                 LOG.trace("Skipping notification for encountered source {}, fetching source failed", id, t);
 117             }
 118         }, MoreExecutors.directExecutor());
 119
 120         return fetchSourceFuture;
 121     }
 122
 123     private synchronized <T extends SchemaSourceRepresentation> void addSource(final PotentialSchemaSource<T> source,
 124             final AbstractSchemaSourceRegistration<T> reg) {
 125         ListMultimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> map =
 126             sources.get(source.getSourceIdentifier());
 127         if (map == null) {
 128             map = ArrayListMultimap.create();
 129             sources.put(source.getSourceIdentifier(), map);
 130         }
 131
 132         map.put(source.getRepresentation(), reg);
 133
 134         final Collection<PotentialSchemaSource<?>> reps = Collections.singleton(source);
 135         for (SchemaListenerRegistration l : listeners) {
 136             l.getInstance().schemaSourceRegistered(reps);
 137         }
 138     }
 139
 140     @SuppressFBWarnings(value = "UPM_UNCALLED_PRIVATE_METHOD",
 141             justification = "https://github.com/spotbugs/spotbugs/issues/811")
 142     private synchronized <T extends SchemaSourceRepresentation> void removeSource(final PotentialSchemaSource<?> source,
 143             final SchemaSourceRegistration<?> reg) {
 144         final Multimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> m =
 145             sources.get(source.getSourceIdentifier());
 146         if (m != null) {
 147             m.remove(source.getRepresentation(), reg);
 148
 149             for (SchemaListenerRegistration l : listeners) {
 150                 l.getInstance().schemaSourceUnregistered(source);
 151             }
 152
 153             if (m.isEmpty()) {
 154                 sources.remove(source.getSourceIdentifier());
 155             }
 156         }
 157     }
 158
 159     @Override
 160     public <T extends SchemaSourceRepresentation> SchemaSourceRegistration<T> registerSchemaSource(
 161             final SchemaSourceProvider<? super T> provider, final PotentialSchemaSource<T> source) {
 162         final PotentialSchemaSource<T> src = source.cachedReference();
 163
 164         final AbstractSchemaSourceRegistration<T> ret = new AbstractSchemaSourceRegistration<>(provider, src) {
 165             @Override
 166             protected void removeRegistration() {
 167                 removeSource(src, this);
 168             }
 169         };
 170
 171         addSource(src, ret);
 172         return ret;
 173     }
 174
 175     @Override
 176     public SchemaListenerRegistration registerSchemaSourceListener(final SchemaSourceListener listener) {
 177         final SchemaListenerRegistration ret = new AbstractSchemaListenerRegistration(listener) {
 178             @Override
 179             protected void removeRegistration() {
 180                 listeners.remove(this);
 181             }
 182         };
 183
 184         synchronized (this) {
 185             final Collection<PotentialSchemaSource<?>> col = new ArrayList<>();
 186             for (Multimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> m
 187                     : sources.values()) {
 188                 for (AbstractSchemaSourceRegistration<?> r : m.values()) {
 189                     col.add(r.getInstance());
 190                 }
 191             }
 192
 193             // Notify first, so translator-type listeners, who react by registering a source
 194             // do not cause infinite loop.
 195             listener.schemaSourceRegistered(col);
 196             listeners.add(ret);
 197         }
 198         return ret;
 199     }
 200
 201     private static class SchemaProviderCostComparator implements Comparator<AbstractSchemaSourceRegistration<?>>,
 202             Serializable {
 203         static final SchemaProviderCostComparator INSTANCE = new SchemaProviderCostComparator();
 204         private static final long serialVersionUID = 1L;
 205
 206         @Override
 207         public int compare(final AbstractSchemaSourceRegistration<?> o1, final AbstractSchemaSourceRegistration<?> o2) {
 208             return o1.getInstance().getCost() - o2.getInstance().getCost();
 209         }
 210
 211         private Object readResolve() {
 212             return INSTANCE;
 213         }
 214     }
 215 }