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/*
* 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.ecmap;
import org.mapdb.DB;
import org.mapdb.DBMaker;
import org.mapdb.Hasher;
import org.mapdb.Serializer;
import org.onosproject.store.serializers.KryoSerializer;
import java.io.File;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* MapDB based implementation of a persistent store.
*/
class MapDbPersistentStore<K, V> implements PersistentStore<K, V> {
private final ExecutorService executor;
private final KryoSerializer serializer;
private final DB database;
private final Map<byte[], byte[]> items;
/**
* Creates a new MapDB based persistent store.
*
* @param filename filename of the database on disk
* @param executor executor to use for tasks that write to the disk
* @param serializer serializer for keys and values
*/
MapDbPersistentStore(String filename, ExecutorService executor,
KryoSerializer serializer) {
this.executor = checkNotNull(executor);
this.serializer = checkNotNull(serializer);
File databaseFile = new File(filename);
database = DBMaker.newFileDB(databaseFile).make();
items = database.createHashMap("items")
.keySerializer(Serializer.BYTE_ARRAY)
.valueSerializer(Serializer.BYTE_ARRAY)
.hasher(Hasher.BYTE_ARRAY)
.makeOrGet();
}
@Override
public void readInto(Map<K, MapValue<V>> items) {
this.items.forEach((keyBytes, valueBytes) ->
items.put(serializer.decode(keyBytes),
serializer.decode(valueBytes)));
}
@Override
public void update(K key, MapValue<V> value) {
executor.submit(() -> updateInternal(key, value));
}
@Override
public void remove(K key) {
executor.submit(() -> removeInternal(key));
}
private void updateInternal(K key, MapValue<V> newValue) {
byte[] keyBytes = serializer.encode(key);
items.compute(keyBytes, (k, existingBytes) -> {
MapValue<V> existing = existingBytes == null ? null :
serializer.decode(existingBytes);
if (existing == null || newValue.isNewerThan(existing)) {
return serializer.encode(newValue);
} else {
return existingBytes;
}
});
database.commit();
}
private void removeInternal(K key) {
byte[] keyBytes = serializer.encode(key);
items.remove(keyBytes);
database.commit();
}
}
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