content: /*
   * 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.cassandra.sidecar.cluster;
  
  import java.util.List;
  
  import org.apache.cassandra.sidecar.cluster.instance.InstanceMetadata;
  import org.apache.cassandra.sidecar.exceptions.NoSuchCassandraInstanceException;
  import org.jetbrains.annotations.NotNull;
  
  /**
   * Maintains metadata of instances maintained by Sidecar.
   */
  public interface InstancesMetadata
  {
      /**
       * Returns metadata associated with the Cassandra instances managed by this Sidecar. The implementer
       * must return a non-null value. When no Cassandra instances are configured, an empty list can be returned.
       *
       * @return metadata of instances owned by the sidecar
       */
      @NotNull
      List<InstanceMetadata> instances();
  
      /**
       * Lookup instance metadata by id.
       *
       * @param id instance's id
       * @return instance meta information
       * @throws NoSuchCassandraInstanceException when the instance with {@code id} does not exist
       */
      @NotNull
      InstanceMetadata instanceFromId(int id) throws NoSuchCassandraInstanceException;
  
      /**
       * Lookup instance metadata by host name.
       *
       * @param hostOrIpAddress hostname or IP address of instance
       * @return instance meta information
       * @throws NoSuchCassandraInstanceException when the instance for {@code host} does not exist
       */
      @NotNull
      InstanceMetadata instanceFromHost(String hostOrIpAddress) throws NoSuchCassandraInstanceException;
  }
  