geode-core/src/main/java/org/apache/geode/internal/cache/eviction/EvictableMap.java

/*
 * 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
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package org.apache.geode.internal.cache.eviction;

import org.apache.geode.internal.cache.persistence.DiskRegionView;

/**
 * A RegionMap should implement EvictableMap if it needs to support Eviction.
 *
 * <p>
 * The eviction action on the map for evicting items must be called while the current thread is free
 * of any map synchronizations.
 */
public interface EvictableMap {

  /**
   * to be called by LocalRegion after any synchronization surrounding a map.put or map.replace call
   * is made. This will then perform the eviction removals, or region.localDestroy() calls to make
   * up for the recent addition.
   */
  void lruUpdateCallback();

  /**
   * Disables lruUpdateCallback in calling thread
   *
   * @return false if it's already disabled
   */
  boolean disableLruUpdateCallback();

  /**
   * Enables lruUpdateCallback in calling thread
   */
  void enableLruUpdateCallback();

  /**
   * if an exception occurs between an LRUEntriesMap put and the call to lruUpdateCallback, then
   * this must be called to allow the thread to continue to work with other regions.
   */
  void resetThreadLocals();

  /**
   * Return true if the lru has exceeded its limit and needs to evict. Note that this method is
   * currently used to prevent disk recovery from faulting in values once the limit is exceeded.
   *
   * @param diskRegionView the disk region whose limit is checked
   */
  boolean lruLimitExceeded(DiskRegionView diskRegionView);

  void lruCloseStats();

  /**
   * Called when an entry is faulted in from disk.
   */
  void lruEntryFaultIn(EvictableEntry entry);

  EvictionController getEvictionController();
}