SimpleLRUCache.java

/*
 * This file is part of Waarp Project (named also Waarp or GG).
 *
 *  Copyright (c) 2019, Waarp SAS, and individual contributors by the @author
 *  tags. See the COPYRIGHT.txt in the distribution for a full listing of
 * individual contributors.
 *
 *  All Waarp Project is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * Waarp is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with
 * Waarp . If not, see <http://www.gnu.org/licenses/>.
 */
package org.waarp.common.lru;

import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Simple LRU Cache
 */
public class SimpleLRUCache<K, V> extends LinkedHashMap<K, V> {
  private static final long serialVersionUID = -3505777964745783339L;
  private final int capacity; // Maximum number of items in the cache.

  public static <K, V> Map<K, V> create(final int capacity) {
    return Collections.synchronizedMap(new SimpleLRUCache<K, V>(capacity));
  }

  public SimpleLRUCache(final int capacity) {
    super(capacity + 1, 1.0f, true); // Pass 'true' for accessOrder.
    this.capacity = capacity;
  }

  @Override
  protected final boolean removeEldestEntry(final Entry<K, V> entry) {
    return size() > capacity;
  }
}