DataRetriever.java

/**
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.ut.biolab.medsavant.client.util;

import java.util.List;

/**
 * @author mfiume, Andrew
 */
public abstract class DataRetriever<T> {
    public abstract List<T> retrieve(int start, int limit) throws Exception;

    public abstract int getTotalNum();

    public abstract void retrievalComplete();

    /**
     * Simplest possible data-retriever just pulls records out of an existing list.
     */
    public static DataRetriever createPrefetchedDataRetriever(final List data) {
        return new DataRetriever() {
            @Override
            public List retrieve(int start, int limit) {
                return data.subList(start, Math.min(start + limit, data.size()));
            }

            @Override
            public int getTotalNum() {
                return data.size();
            }

            @Override
            public void retrievalComplete() {
            };
        };
    }
}