storm-server/src/main/java/org/apache/storm/scheduler/INimbus.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The ASF licenses this file to you 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.apache.storm.scheduler;

import java.util.Collection;
import java.util.Map;
import java.util.Set;

public interface INimbus {
    void prepare(Map<String, Object> topoConf, String schedulerLocalDir);

    /**
     * Returns all slots that are available for the next round of scheduling. A slot is available for scheduling
     * if it is free and can be assigned to, or if it is used and can be reassigned.
     */
    Collection<WorkerSlot> allSlotsAvailableForScheduling(Collection<SupervisorDetails> existingSupervisors,
                                                          Topologies topologies,
                                                          Set<String> topologiesMissingAssignments);

    /**
     * this is called after the assignment is changed in ZK.
     */
    void assignSlots(Topologies topologies, Map<String, Collection<WorkerSlot>> newSlotsByTopologyId);

    /**
     * map from node id to supervisor details.
     */
    String getHostName(Map<String, SupervisorDetails> existingSupervisors, String nodeId);

    IScheduler getForcedScheduler();
}