/*
 * Copyright 2015 Higher Frequency Trading
 *
 *  http://www.higherfrequencytrading.com
 *
 *  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>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>This method if the default implementation for {@link
     * MapEntryOperations#defaultValue}, which might be customized over the default.
     * 
     * @return the default value to be inserted into the map
     * @see MapEntryOperations#defaultValue(MapAbsentEntry)
     */
    @NotNull
    Data<V> defaultValue();
}