StrongReferenceCacheEntry.java

/*******************************************************************************
 * Copyright French Prime minister Office/SGMAP/DINSIC/Vitam Program (2015-2019)
 *
 * contact.vitam@culture.gouv.fr
 *
 * This software is a computer program whose purpose is to implement a digital archiving back-office system managing
 * high volumetry securely and efficiently.
 *
 * This software is governed by the CeCILL 2.1 license under French law and abiding by the rules of distribution of free
 * software. You can use, modify and/ or redistribute the software under the terms of the CeCILL 2.1 license as
 * circulated by CEA, CNRS and INRIA at the following URL "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and rights to copy, modify and redistribute granted by the license,
 * users are provided only with a limited warranty and the software's author, the holder of the economic rights, and the
 * successive licensors have only limited liability.
 *
 * In this respect, the user's attention is drawn to the risks associated with loading, using, modifying and/or
 * developing or reproducing the software by the user in light of its specific status of free software, that may mean
 * that it is complicated to manipulate, and that also therefore means that it is reserved for developers and
 * experienced professionals having in-depth computer knowledge. Users are therefore encouraged to load and test the
 * software's suitability as regards their requirements in conditions enabling the security of their systems and/or data
 * to be ensured and, more generally, to use and operate it in the same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had knowledge of the CeCILL 2.1 license and that you
 * accept its terms.
 *******************************************************************************/
package fr.gouv.vitam.common.lru;

/**
 *
 * author Damian Momot
 *
 */
class StrongReferenceCacheEntry<V> implements InterfaceLruCacheEntry<V> {
    private final V value;

    private long expirationTime;

    /**
     * Creates StrongReferencyCacheEntry with desired ttl
     *
     * @param value
     * @param ttl time to live in milliseconds
     * @throws IllegalArgumentException if ttl is not positive
     */
    StrongReferenceCacheEntry(V value, long ttl) {
        if (ttl <= 0) {
            throw new IllegalArgumentException("ttl must be positive");
        }
        this.value = value;
        expirationTime = System.currentTimeMillis() + ttl;
    }

    /**
     * Returns value if entry is valid, null otherwise.
     *
     * Entry is invalid if it's expired
     *
     * @return value if entry is valid
     */
    @Override
    public V getValue() {
        if (System.currentTimeMillis() > expirationTime) {
            return null;
        } else {
            return value;
        }
    }

    @Override
    public boolean isStillValid(long timeRef) {
        return timeRef <= expirationTime;
    }

    @Override
    public boolean resetTime(long ttl) {
        expirationTime = System.currentTimeMillis() + ttl;
        return true;
    }
}