guava/src/com/google/common/cache/Weigher.java


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/*
 * Copyright (C) 2011 The Guava 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.common.cache;

import com.google.common.annotations.Beta;

/**
 * Calculates the weights of cache entries.
 *
 * @author fry@google.com (Charles Fry)
 * @since 11.0
 */
@Beta
public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);

}