Java tutorial
/* * Copyright 2016-present Open Networking Laboratory * * 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.concurrent.CompletableFuture; import org.onosproject.store.service.AsyncDocumentTree; import org.onosproject.store.service.DocumentPath; import org.onosproject.store.service.DocumentTreeEvent; import org.onosproject.store.service.DocumentTreeListener; import org.onosproject.store.service.Serializer; import org.onosproject.store.service.Versioned; import com.google.common.collect.Maps; /** * Default implementation of {@link AsyncDocumentTree}. * <p> * This implementation delegates execution to a backing tree implemented on top of Atomix framework. * * @param <V> tree node value type. */ public class DefaultDistributedDocumentTree<V> implements AsyncDocumentTree<V> { private final String name; private final AsyncDocumentTree<byte[]> backingTree; private final Serializer serializer; private final Map<DocumentTreeListener<V>, InternalBackingDocumentTreeListener> listeners = Maps .newIdentityHashMap(); DefaultDistributedDocumentTree(String name, AsyncDocumentTree<byte[]> backingTree, Serializer serializer) { this.name = name; this.backingTree = backingTree; this.serializer = serializer; } @Override public String name() { return name; } @Override public Type primitiveType() { return backingTree.primitiveType(); } @Override public DocumentPath root() { return backingTree.root(); } @Override public CompletableFuture<Map<String, Versioned<V>>> getChildren(DocumentPath path) { return backingTree.getChildren(path) .thenApply(map -> Maps.transformValues(map, v -> v.map(serializer::decode))); } @Override public CompletableFuture<Versioned<V>> get(DocumentPath path) { return backingTree.get(path).thenApply(v -> v == null ? null : v.map(serializer::decode)); } @Override public CompletableFuture<Versioned<V>> set(DocumentPath path, V value) { return backingTree.set(path, serializer.encode(value)) .thenApply(v -> v == null ? null : v.map(serializer::decode)); } @Override public CompletableFuture<Boolean> create(DocumentPath path, V value) { return backingTree.create(path, serializer.encode(value)); } @Override public CompletableFuture<Boolean> createRecursive(DocumentPath path, V value) { return backingTree.createRecursive(path, serializer.encode(value)); } @Override public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, long version) { return backingTree.replace(path, serializer.encode(newValue), version); } @Override public CompletableFuture<Boolean> replace(DocumentPath path, V newValue, V currentValue) { return backingTree.replace(path, serializer.encode(newValue), serializer.encode(currentValue)); } @Override public CompletableFuture<Versioned<V>> removeNode(DocumentPath path) { return backingTree.removeNode(path).thenApply(v -> v == null ? null : v.map(serializer::decode)); } @Override public CompletableFuture<Void> addListener(DocumentPath path, DocumentTreeListener<V> listener) { synchronized (listeners) { InternalBackingDocumentTreeListener backingListener = listeners.computeIfAbsent(listener, k -> new InternalBackingDocumentTreeListener(listener)); return backingTree.addListener(path, backingListener); } } @Override public CompletableFuture<Void> removeListener(DocumentTreeListener<V> listener) { synchronized (listeners) { InternalBackingDocumentTreeListener backingListener = listeners.remove(listener); if (backingListener != null) { return backingTree.removeListener(backingListener); } else { return CompletableFuture.completedFuture(null); } } } private class InternalBackingDocumentTreeListener implements DocumentTreeListener<byte[]> { private final DocumentTreeListener<V> listener; InternalBackingDocumentTreeListener(DocumentTreeListener<V> listener) { this.listener = listener; } @Override public void event(DocumentTreeEvent<byte[]> event) { listener.event(new DocumentTreeEvent<V>(event.path(), event.type(), event.newValue().map(v -> v.map(serializer::decode)), event.oldValue().map(v -> v.map(serializer::decode)))); } } }