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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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package com.sun.tools.visualvm.api.caching;

/**
 * An interface for cache
 * <p>
 * A cache is basically a map that can evict its entries according to defined TTL
 * or as a result of the user action
 * @author Jaroslav Bachorik
 */
abstract public class Cache<K,V> {
    /**
     * Retrieves an object from the cache by the given key<br/>
     * If there is no cached version of the object {@linkplain #cacheMiss(java.lang.Object) } is invoked
     * <p>
     * To obtain a cache one needs to call one of {@linkplain CacheFactory} methods
     * </p>
     * @param key The key identifying the object to be retrieved
     * @return Returns the cached object or NULL
     */
    abstract public V retrieveObject(K key);

    abstract public V invalidateObject(K key);

    /**
     * Property getter
     * @return Returns TTL interval in milliseconds
     */
    abstract public long getTTL();

    /**
     * Property setter
     * @param ttl TTL interval in milliseconds
     */
    abstract public void setTTL(long ttl);

}
