/*
 * 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.iotdb.db.queryengine.plan.analyze.cache.schema.dualkeycache.impl;

import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.BiFunction;
import java.util.function.Function;

/**
 * This interface defines the behaviour of a cache entry group, which is mainly accessed via first
 * key from dual key cache and holds all the second keys and cache values indexed by the first key.
 *
 * @param <FK> The first key of cache value.
 * @param <SK> The second key of cache value.
 * @param <V> The cache value.
 * @param <T> The cache entry holding cache value.
 */
interface ICacheEntryGroup<SK, V> {
  CacheEntry<SK, V> getCacheEntry(final SK secondKey);

  Iterator<Map.Entry<SK, CacheEntry<SK, V>>> getAllCacheEntries();

  CacheEntry<SK, V> computeCacheEntry(
      final SK secondKey,
      final Function<AtomicLong, BiFunction<SK, CacheEntry<SK, V>, CacheEntry<SK, V>>> computation);

  CacheEntry<SK, V> computeCacheEntryIfPresent(
      final SK secondKey,
      final Function<AtomicLong, BiFunction<SK, CacheEntry<SK, V>, CacheEntry<SK, V>>> computation);

  long removeCacheEntry(final SK secondKey);

  boolean isEmpty();

  // Metric
  long getMemory();

  int getEntriesCount();
}
