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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.iotdb.session;

import org.apache.iotdb.common.rpc.thrift.TEndPoint;
import org.apache.iotdb.isession.INodeSupplier;

import java.util.Collections;
import java.util.List;
import java.util.Optional;

public class DummyNodesSupplier implements INodeSupplier {

  private final List availableNodes;

  private final QueryEndPointPolicy policy = new RoundRobinPolicy();

  public DummyNodesSupplier(List availableNodes) {
    this.availableNodes = Collections.unmodifiableList(availableNodes);
  }

  @Override
  public void close() {
    // do nothing
  }

  @Override
  public Optional getQueryEndPoint() {
    if (availableNodes == null || availableNodes.isEmpty()) {
      return Optional.empty();
    } else {
      return Optional.of(policy.chooseOne(availableNodes));
    }
  }

  @Override
  public List get() {
    return availableNodes;
  }
}