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/*
* 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.solr.cluster.placement;
import java.util.Set;
import org.apache.solr.cluster.Cluster;
import org.apache.solr.cluster.Node;
import org.apache.solr.cluster.Replica;
import org.apache.solr.cluster.Shard;
import org.apache.solr.cluster.SolrCollection;
/**
* A cluster related placement request that Solr asks a {@link PlacementPlugin} plugin to resolve
* and compute a {@link PlacementPlan} placing one or more {@link Replica}'s of one or more {@link
* Shard}'s of an existing {@link SolrCollection}. The shard might or might not already exist,
* plugin code can easily find out by calling {@link SolrCollection#getShard(String)} with the shard
* name(s) returned by {@link #getShardNames()}.
*
* The set of {@link Node}s on which the replicas should be placed is specified (defaults to
* being equal to the set returned by {@link Cluster#getLiveNodes()}).
*/
public interface PlacementRequest extends ModificationRequest {
/**
* Shard name(s) for which new replicas placement should be computed. The shard(s) might exist or
* not (that's why this method returns a {@link Set} of {@link String}'s and not directly a set of
* {@link Shard} instances).
*
*
Note the Collection API allows specifying the shard name or a {@code _route_} parameter. The
* Solr implementation will convert either specification into the relevant shard name so the
* plugin code doesn't have to worry about this.
*/
Set getShardNames();
/**
* Replicas should only be placed on nodes in the set returned by this method.
*
* When Collection API calls do not specify a specific set of target nodes, replicas can be
* placed on any live node of the cluster. In such cases, this set will be equal to the set of all
* live nodes. The plugin placement code does not need to worry (or care) if a set of nodes was
* explicitly specified or not.
*
* @return never {@code null} and never empty set (if that set was to be empty for any reason, no
* placement would be possible and the Solr infrastructure driving the plugin code would
* detect the error itself rather than calling the plugin).
*/
Set getTargetNodes();
/** Returns the number of replica to create for the given replica type. */
int getCountReplicasToCreate(Replica.ReplicaType replicaType);
}