Support caching in AsyncDocumentTree primitive

Change-Id: I659a5c374891ece7083fa8bad5b1c52c9fa5c8d8

core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CachingAsyncDocumentTree.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed 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.onosproject.store.primitives.impl;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import org.onosproject.store.service.AsyncDocumentTree;
+import org.onosproject.store.service.DocumentPath;
+import org.onosproject.store.service.DocumentTreeListener;
+import org.onosproject.store.service.Versioned;
+import org.slf4j.Logger;
+
+import static org.onosproject.store.service.DistributedPrimitive.Status.INACTIVE;
+import static org.onosproject.store.service.DistributedPrimitive.Status.SUSPENDED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Caching asynchronous document tree.
+ */
+public class CachingAsyncDocumentTree<V> extends DelegatingAsyncDocumentTree<V> implements AsyncDocumentTree<V> {
+    private static final int DEFAULT_CACHE_SIZE = 10000;
+    private final Logger log = getLogger(getClass());
+
+    private final LoadingCache<DocumentPath, CompletableFuture<Versioned<V>>> cache;
+    private final DocumentTreeListener<V> cacheUpdater;
+    private final Consumer<Status> statusListener;
+
+    /**
+     * Default constructor.
+     *
+     * @param backingTree a distributed, strongly consistent map for backing
+     */
+    public CachingAsyncDocumentTree(AsyncDocumentTree<V> backingTree) {
+        this(backingTree, DEFAULT_CACHE_SIZE);
+    }
+
+    /**
+     * Constructor to configure cache size.
+     *
+     * @param backingTree a distributed, strongly consistent map for backing
+     * @param cacheSize the maximum size of the cache
+     */
+    public CachingAsyncDocumentTree(AsyncDocumentTree<V> backingTree, int cacheSize) {
+        super(backingTree);
+        cache = CacheBuilder.newBuilder()
+                .maximumSize(cacheSize)
+                .build(CacheLoader.from(CachingAsyncDocumentTree.super::get));
+        cacheUpdater = event -> {
+            if (!event.newValue().isPresent()) {
+                cache.invalidate(event.path());
+            } else {
+                cache.put(event.path(), CompletableFuture.completedFuture(event.newValue().get()));
+            }
+        };
+        statusListener = status -> {
+            log.debug("{} status changed to {}", this.name(), status);
+            // If the status of the underlying map is SUSPENDED or INACTIVE
+            // we can no longer guarantee that the cache will be in sync.
+            if (status == SUSPENDED || status == INACTIVE) {
+                cache.invalidateAll();
+            }
+        };
+        super.addListener(cacheUpdater);
+        super.addStatusChangeListener(statusListener);
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> get(DocumentPath path) {
+        return cache.getUnchecked(path);
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> set(DocumentPath path, V value) {
+        return super.set(path, value)
+                .whenComplete((r, e) -> cache.invalidate(path));
+    }
+
+    @Override
+    public CompletableFuture<Boolean> create(DocumentPath path, V value) {
+        return super.create(path, value)
+                .whenComplete((r, e) -> cache.invalidate(path));
+    }
+
+    @Override
+    public CompletableFuture<Boolean> createRecursive(DocumentPath path, V value) {
+        return super.createRecursive(path, value)
+                .whenComplete((r, e) -> cache.invalidate(path));
+    }
+
+    @Override
+    public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, long version) {
+        return super.replace(path, newValue, version)
+                .whenComplete((r, e) -> {
+                    if (r) {
+                        cache.invalidate(path);
+                    }
+                });
+    }
+
+    @Override
+    public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, V currentValue) {
+        return super.replace(path, newValue, currentValue)
+                .whenComplete((r, e) -> {
+                    if (r) {
+                        cache.invalidate(path);
+                    }
+                });
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> removeNode(DocumentPath path) {
+        return super.removeNode(path)
+                .whenComplete((r, e) -> cache.invalidate(path));
+    }
+}

core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultDocumentTreeBuilder.java

@@ -47,6 +47,8 @@ public class DefaultDocumentTreeBuilder<V> extends DocumentTreeBuilder<V> {
     @Deprecated
     @Override
     public AsyncDocumentTree<V> build() {
-        return primitiveCreator.newAsyncDocumentTree(name(), serializer(), ordering());
+        AsyncDocumentTree<V> tree = primitiveCreator.newAsyncDocumentTree(name(), serializer(), ordering());
+        tree = relaxedReadConsistency() ? DistributedPrimitives.newCachingDocumentTree(tree) : tree;
+        return tree;
     }
 }

core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DelegatingAsyncDocumentTree.java

@@ -0,0 +1,143 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed 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.onosproject.store.primitives.impl;
+
+import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+
+import com.google.common.base.MoreObjects;
+import org.onosproject.store.primitives.NodeUpdate;
+import org.onosproject.store.primitives.TransactionId;
+import org.onosproject.store.service.AsyncDocumentTree;
+import org.onosproject.store.service.DocumentPath;
+import org.onosproject.store.service.DocumentTreeListener;
+import org.onosproject.store.service.TransactionLog;
+import org.onosproject.store.service.Version;
+import org.onosproject.store.service.Versioned;
+
+/**
+ * Document tree that delegates to an underlying instance.
+ */
+public class DelegatingAsyncDocumentTree<V> extends DelegatingDistributedPrimitive implements AsyncDocumentTree<V> {
+    private final AsyncDocumentTree<V> delegateTree;
+
+    public DelegatingAsyncDocumentTree(AsyncDocumentTree<V> delegateTree) {
+        super(delegateTree);
+        this.delegateTree = delegateTree;
+    }
+
+    @Override
+    public DocumentPath root() {
+        return delegateTree.root();
+    }
+
+    @Override
+    public CompletableFuture<Map<String, Versioned<V>>> getChildren(DocumentPath path) {
+        return delegateTree.getChildren(path);
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> get(DocumentPath path) {
+        return delegateTree.get(path);
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> set(DocumentPath path, V value) {
+        return delegateTree.set(path, value);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> create(DocumentPath path, V value) {
+        return delegateTree.create(path, value);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> createRecursive(DocumentPath path, V value) {
+        return delegateTree.createRecursive(path, value);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, long version) {
+        return delegateTree.replace(path, newValue, version);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, V currentValue) {
+        return delegateTree.replace(path, newValue, currentValue);
+    }
+
+    @Override
+    public CompletableFuture<Versioned<V>> removeNode(DocumentPath path) {
+        return delegateTree.removeNode(path);
+    }
+
+    @Override
+    public CompletableFuture<Void> addListener(DocumentPath path, DocumentTreeListener<V> listener) {
+        return delegateTree.addListener(path, listener);
+    }
+
+    @Override
+    public CompletableFuture<Void> removeListener(DocumentTreeListener<V> listener) {
+        return delegateTree.removeListener(listener);
+    }
+
+    @Override
+    public CompletableFuture<Version> begin(TransactionId transactionId) {
+        return delegateTree.begin(transactionId);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> prepare(TransactionLog<NodeUpdate<V>> transactionLog) {
+        return delegateTree.prepare(transactionLog);
+    }
+
+    @Override
+    public CompletableFuture<Boolean> prepareAndCommit(TransactionLog<NodeUpdate<V>> transactionLog) {
+        return delegateTree.prepareAndCommit(transactionLog);
+    }
+
+    @Override
+    public CompletableFuture<Void> commit(TransactionId transactionId) {
+        return delegateTree.commit(transactionId);
+    }
+
+    @Override
+    public CompletableFuture<Void> rollback(TransactionId transactionId) {
+        return delegateTree.rollback(transactionId);
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("delegateTree", delegateTree)
+                .toString();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(delegateTree);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other instanceof DelegatingAsyncDocumentTree) {
+            DelegatingAsyncDocumentTree<V> that = (DelegatingAsyncDocumentTree) other;
+            return this.delegateTree.equals(that.delegateTree);
+        }
+        return false;
+    }
+}

core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DistributedPrimitives.java

@@ -20,6 +20,7 @@ import org.onosproject.store.service.AsyncConsistentMap;
 import org.onosproject.store.service.AsyncConsistentMultimap;
 import org.onosproject.store.service.AsyncConsistentTreeMap;
 import org.onosproject.store.service.AsyncDistributedSet;
+import org.onosproject.store.service.AsyncDocumentTree;
 
 import java.util.function.Function;
 
@@ -186,4 +187,15 @@ public final class DistributedPrimitives {
                                                         valueEncoder);
     }
 
+    /**
+     * Creates an instance of {@code AsyncDocumentTree} that caches values on get.
+     *
+     * @param tree backing tree
+     * @return caching tree
+     * @param <V> tree value type
+     */
+    public static <V> AsyncDocumentTree<V> newCachingDocumentTree(AsyncDocumentTree<V> tree) {
+        return new CachingAsyncDocumentTree<V>(tree);
+    }
+
 }