001    /*
002     * Copyright (C) 2011 The Guava Authors
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005     * in compliance with the License.  You may obtain a copy of the License at
006     *
007     * http://www.apache.org/licenses/LICENSE-2.0
008     *
009     * Unless required by applicable law or agreed to in writing, software distributed under the License
010     * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011     * or implied.  See the License for the specific language governing permissions and limitations
012     * under the License.
013     */
014    
015    package com.google.common.cache;
016    
017    import com.google.common.annotations.Beta;
018    
019    /**
020     * Calculates the weights of cache entries.
021     *
022     * @author Charles Fry
023     * @since 11.0
024     */
025    @Beta
026    public interface Weigher<K, V> {
027    
028      /**
029       * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
030       * relative to each other.
031       *
032       * @return the weight of the entry; must be non-negative
033       */
034      int weigh(K key, V value);
035    }