None.java

/**
 *
 * This file is part of TRIO.
 *
 * TRIO 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
 * (at your option) any later version.
 *
 * TRIO 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 TRIO.  If not, see <http://www.gnu.org/licenses/>.
 */
/**
 *
 * This file is part of TRIO.
 *
 * TRIO 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 (at your option) any
 * later version.
 *
 * TRIO 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 TRIO. If not, see <http://www.gnu.org/licenses/>.
 */
package eu.diversify.trio.simulation.actions;

import eu.diversify.trio.simulation.Topology;

/**
 * The 'do nothing' action
 */
public class None extends AbstractAction {

    private static final Object lock = new Object();
    private static None instance;

    public static None getInstance() {
        synchronized (lock) {
            if (instance == null) {
                instance = new None();
            }
        }
        return instance;
    }

    private None() {
    }

    @Override
    public Topology executeOn(Topology topology) {
        return topology;
    }

    @Override
    public String toString() {
        return "none";
    }

}