1 files changed, 138 insertions, 0 deletions
diff --git a/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAtomicValue.java b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAtomicValue.java
new file mode 100644
index 00000000..e8c93f31
--- /dev/null
+++ b/framework/src/onos/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultAtomicValue.java
@@ -0,0 +1,138 @@
+/*
+ * 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 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;
+
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+/**
+ * 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();
+    private final MeteringAgent monitor;
+
+    private static final String COMPONENT_NAME = "atomicValue";
+    private static final String GET = "get";
+    private static final String GET_AND_SET = "getAndSet";
+    private static final String COMPARE_AND_SET = "compareAndSet";
+
+    public DefaultAtomicValue(ConsistentMap<String, byte[]> valueMap,
+                              String name,
+                              boolean meteringEnabled,
+                              Serializer serializer) {
+        this.valueMap = valueMap;
+        this.name = name;
+        this.serializer = serializer;
+        this.monitor = new MeteringAgent(COMPONENT_NAME, name, meteringEnabled);
+    }
+
+    @Override
+    public boolean compareAndSet(V expect, V update) {
+        final MeteringAgent.Context newTimer = monitor.startTimer(COMPARE_AND_SET);
+        try {
+            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));
+            }
+        } finally {
+            newTimer.stop(null);
+        }
+    }
+
+    @Override
+    public V get() {
+        final MeteringAgent.Context newTimer = monitor.startTimer(GET);
+        try {
+            Versioned<byte[]> rawValue = valueMap.get(name);
+            return rawValue == null ? null : serializer.decode(rawValue.value());
+        } finally {
+            newTimer.stop(null);
+        }
+    }
+
+    @Override
+    public V getAndSet(V value) {
+        final MeteringAgent.Context newTimer = monitor.startTimer(GET_AND_SET);
+        try {
+            Versioned<byte[]> previousValue = value == null ?
+                    valueMap.remove(name) : valueMap.put(name, serializer.encode(value));
+            return previousValue == null ? null : serializer.decode(previousValue.value());
+        } finally {
+            newTimer.stop(null);
+        }
+    }
+
+    @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));
+        }
+    }
+}