/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.yang.model.repo.util;
import com.google.common.annotations.Beta;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.Lists;
import com.google.common.collect.Multimap;
import com.google.common.util.concurrent.CheckedFuture;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.FutureFallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.GuardedBy;
import org.opendaylight.yangtools.util.concurrent.ExceptionMapper;
import org.opendaylight.yangtools.util.concurrent.ReflectiveExceptionMapper;
import org.opendaylight.yangtools.yang.model.repo.api.MissingSchemaSourceException;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaRepository;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceException;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceFilter;
import org.opendaylight.yangtools.yang.model.repo.api.SchemaSourceRepresentation;
import org.opendaylight.yangtools.yang.model.repo.api.SourceIdentifier;
import org.opendaylight.yangtools.yang.model.repo.spi.PotentialSchemaSource;
import org.opendaylight.yangtools.yang.model.repo.spi.SchemaListenerRegistration;
import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceListener;
import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceProvider;
import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistration;
import org.opendaylight.yangtools.yang.model.repo.spi.SchemaSourceRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Abstract base class for {@link SchemaRepository} implementations. It handles registration
* and lookup of schema sources, subclasses need only to provide their own
* {@link #createSchemaContextFactory(SchemaSourceFilter)} implementation.
*/
@Beta
public abstract class AbstractSchemaRepository implements SchemaRepository, SchemaSourceRegistry {
private static final Logger LOG = LoggerFactory.getLogger(AbstractSchemaRepository.class);
private static final ExceptionMapper<SchemaSourceException> FETCH_MAPPER = ReflectiveExceptionMapper.create("Schema source fetch", SchemaSourceException.class);
/*
* Source identifier -> representation -> provider map. We usually are looking for
* a specific representation of a source.
*/
@GuardedBy("this")
private final Map<SourceIdentifier, ListMultimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>>> sources = new HashMap<>();
/*
* Schema source listeners.
*/
@GuardedBy("this")
private final Collection<SchemaListenerRegistration> listeners = new ArrayList<>();
private static <T extends SchemaSourceRepresentation> CheckedFuture<T, SchemaSourceException> fetchSource(final SourceIdentifier id, final Iterator<AbstractSchemaSourceRegistration<?>> it) {
final AbstractSchemaSourceRegistration<?> reg = it.next();
@SuppressWarnings("unchecked")
final CheckedFuture<? extends T, SchemaSourceException> f = ((SchemaSourceProvider<T>)reg.getProvider()).getSource(id);
return Futures.makeChecked(Futures.withFallback(f, new FutureFallback<T>() {
@Override
public ListenableFuture<T> create(@Nonnull final Throwable t) throws SchemaSourceException {
LOG.debug("Failed to acquire source from {}", reg, t);
if (it.hasNext()) {
return fetchSource(id, it);
}
throw new MissingSchemaSourceException("All available providers exhausted", id, t);
}
}), FETCH_MAPPER);
}
@Override
public <T extends SchemaSourceRepresentation> CheckedFuture<T, SchemaSourceException> getSchemaSource(@Nonnull final SourceIdentifier id, @Nonnull final Class<T> representation) {
final ArrayList<AbstractSchemaSourceRegistration<?>> sortedSchemaSourceRegistrations;
synchronized (this) {
final ListMultimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> srcs = sources.get(id);
if (srcs == null) {
return Futures.immediateFailedCheckedFuture(new MissingSchemaSourceException("No providers registered for source" + id, id));
}
sortedSchemaSourceRegistrations = Lists.newArrayList(srcs.get(representation));
}
// TODO, remove and make sources keep sorted multimap (e.g. ArrayListMultimap with SortedLists)
Collections.sort(sortedSchemaSourceRegistrations, SchemaProviderCostComparator.INSTANCE);
final Iterator<AbstractSchemaSourceRegistration<?>> regs = sortedSchemaSourceRegistrations.iterator();
if (!regs.hasNext()) {
return Futures.immediateFailedCheckedFuture(
new MissingSchemaSourceException("No providers for source " + id + " representation " + representation + " available", id));
}
CheckedFuture<T, SchemaSourceException> fetchSourceFuture = fetchSource(id, regs);
// Add callback to notify cache listeners about encountered schema
Futures.addCallback(fetchSourceFuture, new FutureCallback<T>() {
@Override
public void onSuccess(final T result) {
for (final SchemaListenerRegistration listener : listeners) {
listener.getInstance().schemaSourceEncountered(result);
}
}
@Override
public void onFailure(@Nonnull final Throwable t) {
LOG.trace("Skipping notification for encountered source {}, fetching source failed", id, t);
}
});
return fetchSourceFuture;
}
private synchronized <T extends SchemaSourceRepresentation> void addSource(final PotentialSchemaSource<T> source, final AbstractSchemaSourceRegistration<T> reg) {
ListMultimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> m = sources.get(source.getSourceIdentifier());
if (m == null) {
m = ArrayListMultimap.create();
sources.put(source.getSourceIdentifier(), m);
}
m.put(source.getRepresentation(), reg);
final Collection<PotentialSchemaSource<?>> reps = Collections.singleton(source);
for (SchemaListenerRegistration l : listeners) {
l.getInstance().schemaSourceRegistered(reps);
}
}
private synchronized <T extends SchemaSourceRepresentation> void removeSource(final PotentialSchemaSource<?> source, final SchemaSourceRegistration<?> reg) {
final Multimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> m = sources.get(source.getSourceIdentifier());
if (m != null) {
m.remove(source.getRepresentation(), reg);
for (SchemaListenerRegistration l : listeners) {
l.getInstance().schemaSourceUnregistered(source);
}
if (m.isEmpty()) {
sources.remove(source.getSourceIdentifier());
}
}
}
@Override
public <T extends SchemaSourceRepresentation> SchemaSourceRegistration<T> registerSchemaSource(final SchemaSourceProvider<? super T> provider, final PotentialSchemaSource<T> source) {
final PotentialSchemaSource<T> src = source.cachedReference();
final AbstractSchemaSourceRegistration<T> ret = new AbstractSchemaSourceRegistration<T>(provider, src) {
@Override
protected void removeRegistration() {
removeSource(src, this);
}
};
addSource(src, ret);
return ret;
}
@Override
public SchemaListenerRegistration registerSchemaSourceListener(final SchemaSourceListener listener) {
final SchemaListenerRegistration ret = new AbstractSchemaListenerRegistration(listener) {
@Override
protected void removeRegistration() {
listeners.remove(this);
}
};
synchronized (this) {
final Collection<PotentialSchemaSource<?>> col = new ArrayList<>();
for (Multimap<Class<? extends SchemaSourceRepresentation>, AbstractSchemaSourceRegistration<?>> m : sources.values()) {
for (AbstractSchemaSourceRegistration<?> r : m.values()) {
col.add(r.getInstance());
}
}
// Notify first, so translator-type listeners, who react by registering a source
// do not cause infinite loop.
listener.schemaSourceRegistered(col);
listeners.add(ret);
}
return ret;
}
private static class SchemaProviderCostComparator implements Comparator<AbstractSchemaSourceRegistration<?>> {
public static final SchemaProviderCostComparator INSTANCE = new SchemaProviderCostComparator();
@Override
public int compare(final AbstractSchemaSourceRegistration<?> o1, final AbstractSchemaSourceRegistration<?> o2) {
return o1.getInstance().getCost() - o2.getInstance().getCost();
}
}
}