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.client;
  
  
  import java.util.Collections;
  import java.util.List;
  
  /**
   * A {@link SidecarInstancesProvider} that returns Sidecar instances from a list of instances.
   */
  public class SimpleSidecarInstancesProvider implements SidecarInstancesProvider
  {
      private final List<SidecarInstance> sidecarInstances;
  
      /**
       * Constructs this object with the provided list of Sidecar instances. Creates an unmodifiable copy of the list
       * and keeps a reference to the copy internally.
       *
       * @param sidecarInstances the list of Sidecar instances
       */
      public SimpleSidecarInstancesProvider(List<? extends SidecarInstance> sidecarInstances)
      {
          if (sidecarInstances == null || sidecarInstances.isEmpty())
          {
              String message = "The instances parameter must be non-null and must contain at least one element";
              throw new IllegalArgumentException(message);
          }
          this.sidecarInstances = Collections.unmodifiableList(sidecarInstances);
      }
  
      @Override
      public List<SidecarInstance> instances()
      {
          return sidecarInstances;
      }
  }
  