/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.waveprotocol.box.server.waveserver;
import com.google.common.base.Preconditions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import com.google.common.util.concurrent.ListenableFuture;
import org.waveprotocol.box.server.persistence.PersistenceException;
import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.id.WaveletId;
import org.waveprotocol.wave.model.id.WaveletName;
import org.waveprotocol.wave.util.logging.Log;
import java.util.Iterator;
import java.util.concurrent.ExecutionException;
/**
* The wavelets in a wave.
*
* @author soren@google.com (Soren Lassen)
*/
final class Wave implements Iterable<WaveletContainer> {
private static final Log LOG = Log.get(Wave.class);
private class WaveletCreator<T extends WaveletContainer> extends CacheLoader<WaveletId, T> {
private final WaveletContainer.Factory<T> factory;
private final String waveDomain;
public WaveletCreator(WaveletContainer.Factory<T> factory, String waveDomain) {
this.factory = factory;
this.waveDomain = waveDomain;
}
@Override
public T load(WaveletId waveletId) {
return factory.create(notifiee, WaveletName.of(waveId, waveletId), waveDomain);
}
}
private final WaveId waveId;
/** Future providing already-existing wavelets in storage. */
private final ListenableFuture<ImmutableSet<WaveletId>> lookedupWavelets;
private final LoadingCache<WaveletId, LocalWaveletContainer> localWavelets;
private final LoadingCache<WaveletId, RemoteWaveletContainer> remoteWavelets;
private final WaveletNotificationSubscriber notifiee;
/**
* Creates a wave. The {@code lookupWavelets} future is examined only when a
* query is first made.
*/
public Wave(WaveId waveId,
ListenableFuture<ImmutableSet<WaveletId>> lookedupWavelets,
WaveletNotificationSubscriber notifiee, LocalWaveletContainer.Factory localFactory,
RemoteWaveletContainer.Factory remoteFactory,
String waveDomain) {
this.waveId = waveId;
this.lookedupWavelets = lookedupWavelets;
this.notifiee = notifiee;
this.localWavelets = CacheBuilder.newBuilder().build(
new WaveletCreator<LocalWaveletContainer>(localFactory, waveDomain));
this.remoteWavelets = CacheBuilder.newBuilder().build(
new WaveletCreator<RemoteWaveletContainer>(remoteFactory, waveDomain));
}
@Override
public Iterator<WaveletContainer> iterator() {
return Iterators.unmodifiableIterator(
Iterables.concat(localWavelets.asMap().values(), remoteWavelets.asMap().values()).iterator());
}
LocalWaveletContainer getLocalWavelet(WaveletId waveletId)
throws WaveletStateException {
return getWavelet(waveletId, localWavelets);
}
RemoteWaveletContainer getRemoteWavelet(WaveletId waveletId)
throws WaveletStateException {
return getWavelet(waveletId, remoteWavelets);
}
LocalWaveletContainer getOrCreateLocalWavelet(WaveletId waveletId) {
try {
return localWavelets.get(waveletId);
} catch (ExecutionException ex) {
throw new RuntimeException(ex);
}
}
RemoteWaveletContainer getOrCreateRemoteWavelet(WaveletId waveletId) {
try {
return remoteWavelets.get(waveletId);
} catch (ExecutionException ex) {
throw new RuntimeException(ex);
}
}
private <T extends WaveletContainer> T getWavelet(WaveletId waveletId,
LoadingCache<WaveletId, T> waveletsMap) throws WaveletStateException {
ImmutableSet<WaveletId> storedWavelets;
try {
storedWavelets =
FutureUtil.getResultOrPropagateException(lookedupWavelets, PersistenceException.class);
} catch (PersistenceException e) {
throw new WaveletStateException(
"Failed to lookup wavelet " + WaveletName.of(waveId, waveletId), e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new WaveletStateException(
"Interrupted looking up wavelet " + WaveletName.of(waveId, waveletId), e);
}
if(LOG.isFineLoggable()) {
if(storedWavelets != null) {
if(storedWavelets.contains(waveletId)) {
LOG.fine("Wavelet is in storedWavelets");
}
if(waveletsMap.getIfPresent(waveletId) != null) {
LOG.fine("Wavelet is in wavletsMap");
}
}
}
// Since waveletsMap is a computing map, we must call getIfPresent(waveletId)
// to tell if waveletId is mapped, we cannot test if get(waveletId) returns null.
if (storedWavelets != null && !storedWavelets.contains(waveletId)
&& waveletsMap.getIfPresent(waveletId) == null) {
return null;
} else {
try {
T wavelet = waveletsMap.get(waveletId);
return wavelet;
} catch (CacheLoader.InvalidCacheLoadException ex) {
return null;
} catch (ExecutionException ex) {
throw new RuntimeException(ex);
}
}
}
ListenableFuture<ImmutableSet<WaveletId>> getLookedupWavelets() {
return lookedupWavelets;
}
}