App.java

/**
 * The MIT License
 * Copyright (c) 2014-2016 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.iluwatar.visitor;

/**
 * 
 * Visitor pattern defines mechanism to apply operations on nodes in hierarchy. New operations can
 * be added without altering the node interface.
 * <p>
 * In this example there is a unit hierarchy beginning from {@link Commander}. This hierarchy is
 * traversed by visitors. {@link SoldierVisitor} applies its operation on {@link Soldier}s,
 * {@link SergeantVisitor} on {@link Sergeant}s and so on.
 * 
 */
public class App {

  /**
   * Program entry point
   * 
   * @param args command line args
   */
  public static void main(String[] args) {

    Commander commander =
        new Commander(new Sergeant(new Soldier(), new Soldier(), new Soldier()), new Sergeant(
            new Soldier(), new Soldier(), new Soldier()));
    commander.accept(new SoldierVisitor());
    commander.accept(new SergeantVisitor());
    commander.accept(new CommanderVisitor());

  }
}