com.isotrol.impe3.oi.impl.AbstractMapComponent.java Source code

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Here is the source code for com.isotrol.impe3.oi.impl.AbstractMapComponent.java

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/**
 * This file is part of Port@l
 * Port@l 3.0 - Portal Engine and Management System
 * Copyright (C) 2010  Isotrol, SA.  http://www.isotrol.com
 *
 * Port@l is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Port@l 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Port@l.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.isotrol.impe3.oi.impl;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.isotrol.impe3.es.common.server.AbstractService;
import com.isotrol.impe3.oi.dao.DAO;

/**
 * Abstract class for String -> Long map components.
 * @author Andres Rodriguez.
 * @param <K> Key type.
 */
public abstract class AbstractMapComponent<K> extends AbstractService<DAO> {
    private final LoadingCache<K, Long> cache;

    /** Default constructor. */
    public AbstractMapComponent() {
        final CacheLoader<K, Long> computer = new CacheLoader<K, Long>() {
            public Long load(K from) {
                return compute(from);
            }
        };
        cache = CacheBuilder.newBuilder().softValues().build(computer);
    }

    /**
     * Computes the value of a key.
     * @param key Key to compute.
     * @return The computed value.
     */
    abstract Long compute(K key);

    /**
     * Returns the value for the provided key.
     * @param key String key.
     * @return The numeric value.
     */
    final long get(K key) {
        return cache.getUnchecked(key);
    }
}