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.kafka.streams.integration;
  
  import org.apache.kafka.streams.KafkaStreams;
  import org.apache.kafka.streams.Topology;
  import org.apache.kafka.streams.processor.internals.StreamThread;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Properties;
  
  /**
   *  This class allows to access the {@link KafkaStreams} a {@link StreamThread.StateListener} object.
   *
   */
  public class KafkaStreamsWrapper extends KafkaStreams {
  
      public KafkaStreamsWrapper(final Topology topology,
                                 final Properties props) {
          super(topology, props);
      }
  
      public List<StreamThread> streamThreads() {
          return new ArrayList<>(threads);
      }
  
      /**
       * An app can set a single {@link StreamThread.StateListener} so that the app is notified when state changes.
       *
       * @param listener a new StreamThread state listener
       * @throws IllegalStateException if this {@code KafkaStreams} instance is not in state {@link State#CREATED CREATED}.
       */
      public void setStreamThreadStateListener(final StreamThread.StateListener listener) {
          if (state == State.CREATED) {
              for (final StreamThread thread : threads) {
                  thread.setStateListener(listener);
              }
          } else {
              throw new IllegalStateException("Can only set StateListener in CREATED state. " +
                  "Current state is: " + state);
          }
      }
  }
  