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.hash.HashAbsentEntry;
  import org.jetbrains.annotations.NotNull;
  
  /**
   * Low-level operational context for the situations, when the new entry is going to be inserted
   * into the {@link ChronicleMap}.
   *
   * @param <K> type of the key in {@code ChronicleMap}
   * @param <V> type of the value in {@code ChronicleMap}
   * @see MapEntryOperations
   * @see MapQueryContext#absentEntry()
   */
  public interface MapAbsentEntry<K, V> extends HashAbsentEntry<K> {
  
      @Override
      @NotNull
      MapContext<K, V, ?> context();
  
      /**
       * Inserts the new entry into the map, of {@linkplain #absentKey() the key} and the given {@code
       * value}.
       * <p>
       * <p>This method is the default implementation for {@link MapEntryOperations#insert(
       *MapAbsentEntry, Data)}, which might be customized over the default.
       *
       * @param value the value to insert into the map along with {@link #absentKey() the key}
       * @throws IllegalStateException if some locking/state conditions required to perform insertion
       *                               operation are not met
       * @see MapEntryOperations#insert(MapAbsentEntry, Data)
       */
      void doInsert(Data<V> value);
  
      /**
       * Returns the <i>default</i> (or <i>nil</i>) value, that should be inserted into the map in
       * this context. This is primarily used in {@link ChronicleMap#acquireUsing} operation
       * implementation, i. e. {@link MapMethods#acquireUsing}.
       * <p>
       * <p>This method if the default implementation for {@link
       * DefaultValueProvider#defaultValue(MapAbsentEntry)},
       * which might be customized over the default.
       *
       * @see DefaultValueProvider#defaultValue(MapAbsentEntry)
       */
      @NotNull
      Data<V> defaultValue();
  }
  