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 static com.google.common.base.Preconditions.checkNotNull; import java.util.List; import java.util.Map; import java.util.Set; import java.util.TreeMap; import org.onosproject.cluster.PartitionId; import org.onosproject.store.primitives.DistributedPrimitiveCreator; import org.onosproject.store.service.AsyncAtomicCounter; import org.onosproject.store.service.AsyncAtomicValue; import org.onosproject.store.service.AsyncConsistentMap; import org.onosproject.store.service.AsyncConsistentMultimap; import org.onosproject.store.service.AsyncConsistentTreeMap; import org.onosproject.store.service.AsyncDistributedSet; import org.onosproject.store.service.AsyncDocumentTree; import org.onosproject.store.service.AsyncLeaderElector; import org.onosproject.store.service.Serializer; import org.onosproject.store.service.WorkQueue; import com.google.common.base.Charsets; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import com.google.common.collect.Sets; import com.google.common.hash.Hashing; /** * {@code DistributedPrimitiveCreator} that federates responsibility for creating * distributed primitives to a collection of other {@link DistributedPrimitiveCreator creators}. */ public class FederatedDistributedPrimitiveCreator implements DistributedPrimitiveCreator { private final TreeMap<PartitionId, DistributedPrimitiveCreator> members; private final List<PartitionId> sortedMemberPartitionIds; public FederatedDistributedPrimitiveCreator(Map<PartitionId, DistributedPrimitiveCreator> members) { this.members = Maps.newTreeMap(); this.members.putAll(checkNotNull(members)); this.sortedMemberPartitionIds = Lists.newArrayList(members.keySet()); } @Override public <K, V> AsyncConsistentMap<K, V> newAsyncConsistentMap(String name, Serializer serializer) { checkNotNull(name); checkNotNull(serializer); Map<PartitionId, AsyncConsistentMap<K, V>> maps = Maps.transformValues(members, partition -> partition.newAsyncConsistentMap(name, serializer)); Hasher<K> hasher = key -> { int hashCode = Hashing.sha256().hashBytes(serializer.encode(key)).asInt(); return sortedMemberPartitionIds.get(Math.abs(hashCode) % members.size()); }; return new PartitionedAsyncConsistentMap<>(name, maps, hasher); } @Override public <V> AsyncConsistentTreeMap<V> newAsyncConsistentTreeMap(String name, Serializer serializer) { return getCreator(name).newAsyncConsistentTreeMap(name, serializer); } @Override public <K, V> AsyncConsistentMultimap<K, V> newAsyncConsistentSetMultimap(String name, Serializer serializer) { return getCreator(name).newAsyncConsistentSetMultimap(name, serializer); } @Override public <E> AsyncDistributedSet<E> newAsyncDistributedSet(String name, Serializer serializer) { return DistributedPrimitives.newSetFromMap(newAsyncConsistentMap(name, serializer)); } @Override public AsyncAtomicCounter newAsyncCounter(String name) { return getCreator(name).newAsyncCounter(name); } @Override public <V> AsyncAtomicValue<V> newAsyncAtomicValue(String name, Serializer serializer) { return getCreator(name).newAsyncAtomicValue(name, serializer); } @Override public AsyncLeaderElector newAsyncLeaderElector(String name) { checkNotNull(name); Map<PartitionId, AsyncLeaderElector> leaderElectors = Maps.transformValues(members, partition -> partition.newAsyncLeaderElector(name)); Hasher<String> hasher = topic -> { int hashCode = Hashing.sha256().hashString(topic, Charsets.UTF_8).asInt(); return sortedMemberPartitionIds.get(Math.abs(hashCode) % members.size()); }; return new PartitionedAsyncLeaderElector(name, leaderElectors, hasher); } @Override public <E> WorkQueue<E> newWorkQueue(String name, Serializer serializer) { return getCreator(name).newWorkQueue(name, serializer); } @Override public <V> AsyncDocumentTree<V> newAsyncDocumentTree(String name, Serializer serializer) { return getCreator(name).newAsyncDocumentTree(name, serializer); } @Override public Set<String> getAsyncConsistentMapNames() { return members.values().stream().map(DistributedPrimitiveCreator::getAsyncConsistentMapNames) .reduce(Sets::union).orElse(ImmutableSet.of()); } @Override public Set<String> getAsyncAtomicCounterNames() { return members.values().stream().map(DistributedPrimitiveCreator::getAsyncAtomicCounterNames) .reduce(Sets::union).orElse(ImmutableSet.of()); } @Override public Set<String> getWorkQueueNames() { return members.values().stream().map(DistributedPrimitiveCreator::getWorkQueueNames).reduce(Sets::union) .orElse(ImmutableSet.of()); } /** * Returns the {@code DistributedPrimitiveCreator} to use for hosting a primitive. * @param name primitive name * @return primitive creator */ private DistributedPrimitiveCreator getCreator(String name) { int hashCode = Hashing.sha256().hashString(name, Charsets.UTF_8).asInt(); return members.get(sortedMemberPartitionIds.get(Math.abs(hashCode) % members.size())); } }