code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed 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 net.openhft.chronicle.map;
  
  import net.openhft.chronicle.hash.Data;
  import net.openhft.chronicle.set.SetEntry;
  import org.jetbrains.annotations.NotNull;
  
  /**
   * A context of a <i>present</i> entry in the {@link ChronicleMap}.
   *
   * @param <K> the map key type
   * @param <V> the map value type
   * @see MapEntryOperations
   * @see MapQueryContext#entry()
   */
  public interface MapEntry<K, V> extends SetEntry<K> {
      @Override
      @NotNull
      MapContext<K, V, ?> context();
  
      /**
       * Returns the entry value.
       */
      @NotNull
      Data<V> value();
  
      /**
       * Replaces the entry's value with the given {@code newValue}.
       * <p>
       * <p>This method is the default implementation for {@link MapEntryOperations#replaceValue(
       *MapEntry, Data)}, which might be customized over the default.
       *
       * @param newValue the value to be put into the map instead of the {@linkplain #value() current
       *                 value}
       * @throws IllegalStateException if some locking/state conditions required to perform replace
       *                               operation are not met
       */
      void doReplaceValue(Data<V> newValue);
  
      /**
       * Removes the entry from the map.
       * <p>
       * <p>This method is the default implementation for {@link MapEntryOperations#remove(MapEntry)},
       * which might be customized over the default.
       */
      @Override
      void doRemove();
  }
  