/*
* Copyright © 2014 Cask Data, Inc.
*
* 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.
*/
/**
* This package contains classes for performing coordination of resource allocation.
*
* The two important classes are {@link co.cask.cdap.common.zookeeper.coordination.ResourceCoordinator}
* and {@link co.cask.cdap.common.zookeeper.coordination.ResourceCoordinatorClient}.
*
* The {@link co.cask.cdap.common.zookeeper.coordination.ResourceCoordinator}
* is expected to have single instance running and is responsible for matching
* {@link co.cask.cdap.common.zookeeper.coordination.PartitionReplica} to
* {@link org.apache.twill.discovery.Discoverable}, based on the specification as described by
* {@link co.cask.cdap.common.zookeeper.coordination.ResourceRequirement}. The actual strategy used for
* the matching is controlled by {@link co.cask.cdap.common.zookeeper.coordination.AssignmentStrategy}.
*
* The {@link co.cask.cdap.common.zookeeper.coordination.ResourceCoordinatorClient} is for the
* {@link org.apache.twill.discovery.Discoverable}s who are interested in handling changes in resource
* assignment. It is also served as a admin interface for create/update/delete of
* {@link co.cask.cdap.common.zookeeper.coordination.ResourceRequirement}.
*
* The coordination service is designed in a way that the interruption of
* {@link co.cask.cdap.common.zookeeper.coordination.ResourceCoordinator} availability will only affect
* reassignment, triggered by new/update of resource requirement or changes in Discoverable. All
* current resource assignment would not be affected, meaning all clients should still be able to operate
* normally as long as they are up and running.
*/
package co.cask.cdap.common.zookeeper.coordination;