com.hazelcast.core.PartitionService Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2016, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.core;
import com.hazelcast.partition.PartitionLostListener;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* PartitionService allows you to query {@link Partition}s and attach/detach {@link MigrationListener}s to listen to partition
* migration events.
*
* The methods on the PartitionService are thread-safe.
*
* @see Partition
* @see MigrationListener
* @see PartitionLostListener
*/
public interface PartitionService {
/**
* Returns a set containing all the {@link Partition}s in the cluster.
*
* @return all partitions in the cluster
*/
Set getPartitions();
/**
* Returns the partition that the given key belongs to.
*
* @param key the given key
* @return the partition that the given key belongs to
* todo: what about null.
*/
Partition getPartition(Object key);
/**
* Generates a random partition key. This is useful if you want to partition data in the same partition,
* but you do not care which partition it is going to be.
*
* The returned value will never be null.
*
* This method is deprecated since Hazelcast 3.5. If you need a random partition-key, you can use e.g. a
* random number, random string or UUID for that.
*
* @return the random partition key.
*/
@Deprecated
String randomPartitionKey();
/**
* Adds a MigrationListener.
*
* The addMigrationListener returns a register-id. This id is needed to remove the MigrationListener using the
* {@link #removeMigrationListener(String)} method.
*
* There is no check for duplicate registrations, so if you register the listener twice, it will get events twice.
*
* @param migrationListener the added MigrationListener
* @return returns the registration id for the MigrationListener.
* @throws java.lang.NullPointerException if migrationListener is null.
* @throws UnsupportedOperationException if this operation isn't supported. For example on the client side it isn't possible
* to add a MigrationListener.
* @see #removeMigrationListener(String)
*/
String addMigrationListener(MigrationListener migrationListener);
/**
* Removes a MigrationListener.
*
* If the same MigrationListener is registered multiple times, it needs to be removed multiple times.
*
* This method can safely be called multiple times for the same registration-id; every subsequent call is just ignored.
*
* @param registrationId the registration id of the listener to remove.
* @return true if the listener is removed, false otherwise.
* @throws java.lang.NullPointerException if registrationId is null.
* @throws UnsupportedOperationException if this operation isn't supported. For example, on the client side it isn't possible
* to add/remove a MigrationListener.
* @see #addMigrationListener(MigrationListener)
*/
boolean removeMigrationListener(String registrationId);
/**
* Adds a PartitionLostListener.
*
* The addPartitionLostListener returns a register-id. This id is needed to remove the PartitionLostListener using the
* {@link #removePartitionLostListener(String)} method.
*
* There is no check for duplicate registrations, so if you register the listener twice, it will get events twice.
* IMPORTANT: Please @see com.hazelcast.partition.PartitionLostListener for weaknesses
*
* @param partitionLostListener the added PartitionLostListener
* @return returns the registration id for the PartitionLostListener.
* @throws java.lang.NullPointerException if partitionLostListener is null.
* @see #removePartitionLostListener(String)
*/
String addPartitionLostListener(PartitionLostListener partitionLostListener);
/**
* Removes a PartitionLostListener.
*
* If the same PartitionLostListener is registered multiple times, it needs to be removed multiple times.
*
* This method can safely be called multiple times for the same registration-id; every subsequent call is just ignored.
*
* @param registrationId the registration id of the listener to remove.
* @return true if the listener is removed, false otherwise.
* @throws java.lang.NullPointerException if registrationId is null.
*
* @see #addPartitionLostListener(PartitionLostListener)
*/
boolean removePartitionLostListener(String registrationId);
/**
* Checks whether the cluster is in a safe state. When in a safe state,
* it is permissible to shut down a server instance.
*
* @return true if there are no partitions being migrated, and there are sufficient backups
* for each partition per the configuration; false otherwise.
* @since 3.3
*/
boolean isClusterSafe();
/**
* Check if the given member is safe to shutdown, meaning check if at least one backup of the partitions
* owned by the given member are in sync with primary.
*
* @param member the cluster member to query.
* @return true if the member is in a safe state, false otherwise.
* @since 3.3
*/
boolean isMemberSafe(Member member);
/**
* Check if the local member is safe to shutdown, meaning check if at least one backup of the partitions
* owned by the local member are in sync with primary.
*
* @since 3.3
*/
boolean isLocalMemberSafe();
/**
* Force the local member to be safe by checking and syncing partitions owned by the local member
* with at least one of the backups.
* @param timeout the time limit for checking/syncing with the backup
* @param unit the unit of time for timeout
*
* @since 3.3
*/
boolean forceLocalMemberToBeSafe(long timeout, TimeUnit unit);
}