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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.consistent.impl;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.onlab.util.HexString;
import org.onosproject.store.service.ConsistentMap;
import org.onosproject.store.service.DatabaseUpdate;
import org.onosproject.store.service.Serializer;
import org.onosproject.store.service.TransactionContext;
import org.onosproject.store.service.TransactionalMap;
import org.onosproject.store.service.Versioned;
import static com.google.common.base.Preconditions.*;
import com.google.common.base.Objects;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
/**
* Default Transactional Map implementation that provides a repeatable reads
* transaction isolation level.
*
* @param <K> key type
* @param <V> value type.
*/
public class DefaultTransactionalMap<K, V> implements TransactionalMap<K, V> {
private final TransactionContext txContext;
private static final String TX_CLOSED_ERROR = "Transaction is closed";
private final ConsistentMap<K, V> backingMap;
private final String name;
private final Serializer serializer;
private final Map<K, Versioned<V>> readCache = Maps.newConcurrentMap();
private final Map<K, V> writeCache = Maps.newConcurrentMap();
private final Set<K> deleteSet = Sets.newConcurrentHashSet();
private static final String ERROR_NULL_VALUE = "Null values are not allowed";
private static final String ERROR_NULL_KEY = "Null key is not allowed";
private final LoadingCache<K, String> keyCache = CacheBuilder.newBuilder()
.softValues()
.build(new CacheLoader<K, String>() {
@Override
public String load(K key) {
return HexString.toHexString(serializer.encode(key));
}
});
protected K dK(String key) {
return serializer.decode(HexString.fromHexString(key));
}
public DefaultTransactionalMap(
String name,
ConsistentMap<K, V> backingMap,
TransactionContext txContext,
Serializer serializer) {
this.name = name;
this.backingMap = backingMap;
this.txContext = txContext;
this.serializer = serializer;
}
@Override
public V get(K key) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
checkNotNull(key, ERROR_NULL_KEY);
if (deleteSet.contains(key)) {
return null;
}
V latest = writeCache.get(key);
if (latest != null) {
return latest;
} else {
Versioned<V> v = readCache.computeIfAbsent(key, k -> backingMap.get(k));
return v != null ? v.value() : null;
}
}
@Override
public V put(K key, V value) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
checkNotNull(value, ERROR_NULL_VALUE);
V latest = get(key);
writeCache.put(key, value);
deleteSet.remove(key);
return latest;
}
@Override
public V remove(K key) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
V latest = get(key);
if (latest != null) {
writeCache.remove(key);
deleteSet.add(key);
}
return latest;
}
@Override
public boolean remove(K key, V value) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
checkNotNull(value, ERROR_NULL_VALUE);
V latest = get(key);
if (Objects.equal(value, latest)) {
remove(key);
return true;
}
return false;
}
@Override
public boolean replace(K key, V oldValue, V newValue) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
checkNotNull(oldValue, ERROR_NULL_VALUE);
checkNotNull(newValue, ERROR_NULL_VALUE);
V latest = get(key);
if (Objects.equal(oldValue, latest)) {
put(key, newValue);
return true;
}
return false;
}
@Override
public V putIfAbsent(K key, V value) {
checkState(txContext.isOpen(), TX_CLOSED_ERROR);
checkNotNull(value, ERROR_NULL_VALUE);
V latest = get(key);
if (latest == null) {
put(key, value);
}
return latest;
}
protected List<DatabaseUpdate> prepareDatabaseUpdates() {
List<DatabaseUpdate> updates = Lists.newLinkedList();
deleteSet.forEach(key -> {
Versioned<V> original = readCache.get(key);
if (original != null) {
updates.add(DatabaseUpdate.newBuilder()
.withMapName(name)
.withType(DatabaseUpdate.Type.REMOVE_IF_VERSION_MATCH)
.withKey(keyCache.getUnchecked(key))
.withCurrentVersion(original.version())
.build());
}
});
writeCache.forEach((key, value) -> {
Versioned<V> original = readCache.get(key);
if (original == null) {
updates.add(DatabaseUpdate.newBuilder()
.withMapName(name)
.withType(DatabaseUpdate.Type.PUT_IF_ABSENT)
.withKey(keyCache.getUnchecked(key))
.withValue(serializer.encode(value))
.build());
} else {
updates.add(DatabaseUpdate.newBuilder()
.withMapName(name)
.withType(DatabaseUpdate.Type.PUT_IF_VERSION_MATCH)
.withKey(keyCache.getUnchecked(key))
.withCurrentVersion(original.version())
.withValue(serializer.encode(value))
.build());
}
});
return updates;
}
/**
* Discards all changes made to this transactional map.
*/
protected void rollback() {
readCache.clear();
writeCache.clear();
deleteSet.clear();
}
}
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