LRUMap.java

/*
 * Copyright 2017 ZXing authors
 *
 * 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 com.google.zxing.web;

import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Map with maximum size that removes least-recently-accessed entries when full.
 *
 * @param <K> map key type
 * @param <V> map value type
 */
final class LRUMap<K,V> extends LinkedHashMap<K,V> {

  private final int maxSize;

  LRUMap(int maxSize) {
    super(100, 0.75f, true);
    this.maxSize = maxSize;
  }

  @Override
  protected boolean removeEldestEntry(Map.Entry<K,V> eldest) {
    return size() > maxSize;
  }

}