FirstElementServiceSelectionStrategy.java

/**
 * Copyright (c) Codice Foundation
 * <p>
 * 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 3 of the
 * License, or any later version.
 * <p>
 * This program 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. A copy of the GNU Lesser General Public License
 * is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 */

package ddf.catalog.util.impl;

import java.util.SortedSet;

import org.osgi.framework.ServiceReference;

/**
 *
 * This is a basic implementation of ServiceSelectionStrategy which returns the first
 * element from the supplied java.util.SortedSet.
 *
 * @param <T> - The type of the service to be returned.
 * {@link ddf.catalog.util.impl.ServiceSelectionStrategy}
 *
 */

public class FirstElementServiceSelectionStrategy<T> implements ServiceSelectionStrategy<T> {

    /**
     *
     * @param serviceSet - An unmodifiable, sorted list of all services bound to the
     *                   ServiceSelector instance.
     * @return the first element of serviceSet.
     */

    public ServiceReference<T> selectService(SortedSet<ServiceReference<T>> serviceSet) {
        return serviceSet.first();
    }
}