Support caching in AsyncDocumentTree primitive

Change-Id: I659a5c374891ece7083fa8bad5b1c52c9fa5c8d8
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DelegatingAsyncDocumentTree.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DelegatingAsyncDocumentTree.java
new file mode 100644
index 0000000..6182c48
--- /dev/null
+++ b/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;
+    }
+}