| /* |
| * Copyright 2015 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.consistent.impl; |
| |
| import java.util.Set; |
| import java.util.concurrent.CopyOnWriteArraySet; |
| |
| import org.onosproject.store.service.AtomicValue; |
| import org.onosproject.store.service.AtomicValueEvent; |
| import org.onosproject.store.service.AtomicValueEventListener; |
| import org.onosproject.store.service.ConsistentMap; |
| import org.onosproject.store.service.MapEvent; |
| import org.onosproject.store.service.MapEventListener; |
| import org.onosproject.store.service.Serializer; |
| import org.onosproject.store.service.Versioned; |
| |
| /** |
| * Default implementation of AtomicValue. |
| * |
| * @param <V> value type |
| */ |
| public class DefaultAtomicValue<V> implements AtomicValue<V> { |
| |
| private final Set<AtomicValueEventListener<V>> listeners = new CopyOnWriteArraySet<>(); |
| private final ConsistentMap<String, byte[]> valueMap; |
| private final String name; |
| private final Serializer serializer; |
| private final MapEventListener<String, byte[]> mapEventListener = new InternalMapEventListener(); |
| |
| public DefaultAtomicValue(ConsistentMap<String, byte[]> valueMap, |
| String name, |
| Serializer serializer) { |
| this.valueMap = valueMap; |
| this.name = name; |
| this.serializer = serializer; |
| } |
| |
| @Override |
| public boolean compareAndSet(V expect, V update) { |
| if (expect == null) { |
| if (update == null) { |
| return true; |
| } |
| return valueMap.putIfAbsent(name, serializer.encode(update)) == null; |
| } else { |
| if (update == null) { |
| return valueMap.remove(name, serializer.encode(expect)); |
| } |
| return valueMap.replace(name, serializer.encode(expect), serializer.encode(update)); |
| } |
| } |
| |
| @Override |
| public V get() { |
| Versioned<byte[]> rawValue = valueMap.get(name); |
| return rawValue == null ? null : serializer.decode(rawValue.value()); |
| } |
| |
| @Override |
| public V getAndSet(V value) { |
| Versioned<byte[]> previousValue = value == null ? |
| valueMap.remove(name) : valueMap.put(name, serializer.encode(value)); |
| return previousValue == null ? null : serializer.decode(previousValue.value()); |
| } |
| |
| @Override |
| public void set(V value) { |
| getAndSet(value); |
| } |
| |
| @Override |
| public void addListener(AtomicValueEventListener<V> listener) { |
| synchronized (listeners) { |
| if (listeners.add(listener)) { |
| if (listeners.size() == 1) { |
| valueMap.addListener(mapEventListener); |
| } |
| } |
| } |
| } |
| |
| @Override |
| public void removeListener(AtomicValueEventListener<V> listener) { |
| synchronized (listeners) { |
| if (listeners.remove(listener)) { |
| if (listeners.size() == 0) { |
| valueMap.removeListener(mapEventListener); |
| } |
| } |
| } |
| } |
| |
| private class InternalMapEventListener implements MapEventListener<String, byte[]> { |
| |
| @Override |
| public void event(MapEvent<String, byte[]> mapEvent) { |
| V newValue = mapEvent.type() == MapEvent.Type.REMOVE ? null : serializer.decode(mapEvent.value().value()); |
| AtomicValueEvent<V> atomicValueEvent = new AtomicValueEvent<>(name, AtomicValueEvent.Type.UPDATE, newValue); |
| listeners.forEach(l -> l.event(atomicValueEvent)); |
| } |
| } |
| } |