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;
  
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.streams.state.HostInfo;
  
  import java.util.Set;
  
  /**
   * Metadata of a Kafka Streams client.
   */
  public interface StreamsMetadata {
  
      /**
       * The value of {@link StreamsConfig#APPLICATION_SERVER_CONFIG} configured for the Streams
       * client.
       *
       * @return {@link HostInfo} corresponding to the Streams client
       */
      HostInfo hostInfo();
  
      /**
       * Names of the state stores assigned to active tasks of the Streams client.
       *
       * @return names of the state stores assigned to active tasks
       */
      Set<String> stateStoreNames();
  
      /**
       * Source topic partitions of the active tasks of the Streams client.
       *
       * @return source topic partitions of the active tasks
       */
      Set<TopicPartition> topicPartitions();
  
      /**
       * Source topic partitions for which the instance acts as standby.
       *
       * @return source topic partitions of the standby tasks
       */
      Set<TopicPartition> standbyTopicPartitions();
  
      /**
       * Names of the state stores assigned to standby tasks of the Streams client.
       *
       * @return names of the state stores assigned to standby tasks
       */
      Set<String> standbyStateStoreNames();
  
      /**
       * Host where the Streams client runs. 
       *
       * <p>This method is equivalent to {@code StreamsMetadata.hostInfo().host();}
       *
       * @return the host where the Streams client runs
       */
      String host();
  
      /**
       * Port on which the Streams client listens.
       * 
       * <p>This method is equivalent to {@code StreamsMetadata.hostInfo().port();}
       *
       * @return the port on which Streams client listens
       */
      int port();
  
      /**
       * Compares the specified object with this StreamsMetadata. Returns {@code true} if and only if the specified object is
       * also a StreamsMetadata and for both {@code hostInfo()} are equal, and {@code stateStoreNames()}, {@code topicPartitions()},
       * {@code standbyStateStoreNames()}, and {@code standbyTopicPartitions()} contain the same elements.
       *
       * @return {@code true} if this object is the same as the obj argument; {@code false} otherwise.
       */
      boolean equals(Object o);
  
      /**
       * Returns the hash code value for this TaskMetadata. The hash code of a list is defined to be the result of the following calculation:
       * <pre>
       * {@code
       * Objects.hash(hostInfo(), stateStoreNames(), topicPartitions(), standbyStateStoreNames(), standbyTopicPartitions());
       * }
       * </pre>
       *
       * @return a hash code value for this object.
       */
      int hashCode();
  
  }
  