| /* |
| * 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.apache.jackrabbit.oak.plugins.document; |
| |
| import com.google.common.cache.Cache; |
| import com.google.common.cache.CacheBuilder; |
| import com.google.common.collect.Iterables; |
| |
| import org.apache.jackrabbit.oak.cache.CacheStats; |
| import org.apache.jackrabbit.oak.plugins.document.util.RevisionsKey; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import static org.apache.jackrabbit.oak.plugins.document.util.Utils.isLocalChange; |
| |
| /** |
| * Implements a tiered diff cache which consists of a {@link LocalDiffCache} and |
| * a {@link MemoryDiffCache}. |
| */ |
| class TieredDiffCache extends DiffCache { |
| |
| /** |
| * A small cache of local diff cache misses to prevent repeated calls with |
| * the same revision vector range. |
| */ |
| private Cache<RevisionsKey, RevisionsKey> localDiffMisses |
| = CacheBuilder.newBuilder().maximumSize(128).build(); |
| |
| private final int clusterId; |
| private final DiffCache localCache; |
| private final DiffCache memoryCache; |
| |
| TieredDiffCache(DocumentNodeStoreBuilder<?> builder, int clusterId) { |
| this.clusterId = clusterId; |
| this.localCache = new LocalDiffCache(builder); |
| this.memoryCache = new MemoryDiffCache(builder); |
| } |
| |
| @Override |
| public String getChanges(@NotNull RevisionVector from, |
| @NotNull RevisionVector to, |
| @NotNull Path path, |
| @Nullable Loader loader) { |
| // do not check local cache when changes are external |
| if (isLocalChange(from, to, clusterId)) { |
| // do not read from the localCache when there was a previous miss |
| // with the same key |
| RevisionsKey k = new RevisionsKey(from, to); |
| if (localDiffMisses.getIfPresent(k) == null) { |
| // check local without loader and fallback to |
| // memory cache when there is a cache miss |
| String changes = localCache.getChanges(from, to, path, null); |
| if (changes != null) { |
| return changes; |
| } |
| // remember cache miss |
| localDiffMisses.put(k, k); |
| } |
| } |
| return memoryCache.getChanges(from, to, path, loader); |
| } |
| |
| /** |
| * Creates a new entry in the {@link LocalDiffCache} for local changes |
| * and {@link MemoryDiffCache} for external changes |
| * |
| * @param from the from revision. |
| * @param to the to revision. |
| * @return the new entry. |
| */ |
| @NotNull |
| @Override |
| public Entry newEntry(@NotNull RevisionVector from, @NotNull RevisionVector to, boolean local) { |
| if (local) { |
| return localCache.newEntry(from, to, true); |
| } else { |
| return memoryCache.newEntry(from, to, false); |
| } |
| } |
| |
| @NotNull |
| @Override |
| public Iterable<CacheStats> getStats() { |
| return Iterables.concat(localCache.getStats(), memoryCache.getStats()); |
| } |
| |
| @Override |
| public void invalidateAll() { |
| localCache.invalidateAll(); |
| memoryCache.invalidateAll(); |
| } |
| } |