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.server.immutable;
  
  import org.apache.kafka.server.immutable.pcollections.PCollectionsImmutableMap;
  
  import java.util.Map;
  
  /**
   * A persistent Hash-based Map wrapper.
   * java.util.Map methods that mutate in-place will throw UnsupportedOperationException
   *
   * @param <K> the key type
   * @param <V> the value type
   */
  public interface ImmutableMap<K, V> extends Map<K, V> {
      /**
       * @return a wrapped hash-based persistent map that is empty
       * @param <K> the key type
       * @param <V> the value type
       */
      static <K, V> ImmutableMap<K, V> empty() {
          return PCollectionsImmutableMap.empty();
      }
  
      /**
       * @param key the key
       * @param value the value
       * @return a wrapped hash-based persistent map that has a single mapping
       * @param <K> the key type
       * @param <V> the value type
       */
      static <K, V> ImmutableMap<K, V> singleton(K key, V value) {
          return PCollectionsImmutableMap.singleton(key, value);
      }
  
      /**
       * @param key the key
       * @param value the value
       * @return a wrapped persistent map that differs from this one in that the given mapping is added (if necessary)
       */
      ImmutableMap<K, V> updated(K key, V value);
  
      /**
       * @param key the key
       * @return a wrapped persistent map that differs from this one in that the given mapping is removed (if necessary)
       */
      ImmutableMap<K, V> removed(K key);
  }
  