java设计模式之中介者模式

/**
 * @author jifang
 * @since 16/8/28 下午4:22.
 */
public abstract class Country {

 protected UnitedNations mediator;

 private String name;

 public Country(UnitedNations mediator, String name) {
  this.mediator = mediator;
  this.name = name;
 }

 public String getName() {
  return name;
 }

 protected abstract void declare(String msg);

 protected abstract void receive(String msg);
}

class USA extends Country {

 public USA(UnitedNations mediator, String name) {
  super(mediator, name);
 }

 @Override
 public void declare(String msg) {
  mediator.declare(this, msg);
 }

 @Override
 public void receive(String msg) {
  System.out.println("美国接收到: [" + msg + "]");
 }
}

class Iraq extends Country {

 public Iraq(UnitedNations mediator, String name) {
  super(mediator, name);
 }

 @Override
 public void declare(String msg) {
  mediator.declare(this, msg);
 }

 @Override
 public void receive(String msg) {
  System.out.println("伊拉克接收到: [" + msg + "]");
 }
}

class China extends Country {

 public China(UnitedNations mediator, String name) {
  super(mediator, name);
 }

 @Override
 public void declare(String msg) {
  mediator.declare(this, msg);
 }

 @Override
 public void receive(String msg) {
  System.out.println("中国接收到: [" + msg + "]");
 }
}

public abstract class UnitedNations {

 protected List<Country> countries = new LinkedList<>();

 public void register(Country country) {
  countries.add(country);
 }

 public void remove(Country country) {
  countries.remove(country);
 }

 protected abstract void declare(Country country, String msg);
}

class UnitedNationsSecurityCouncil extends UnitedNations {

 /**
  * 安理会在中间作出调停
  *
  * @param country
  * @param msg
  */
 @Override
 protected void declare(Country country, String msg) {
  for (Country toCountry : countries) {
   if (!toCountry.equals(country)) {
    String name = country.getName();
    toCountry.receive(name + "平和的说: " + msg);
   }
  }
 }
}

public class Client {

 @Test
 public void client() {
  UnitedNations mediator = new UnitedNationsSecurityCouncil();

  Country usa = new USA(mediator, "美国");
  Country china = new China(mediator, "中国");
  Country iraq = new Iraq(mediator, "伊拉克");

  mediator.register(usa);
  mediator.register(china);
  mediator.register(iraq);

  usa.declare("我要打伊拉克, 谁管我跟谁急!!!");
  System.out.println("----------");
  china.declare("我们强烈谴责!!!");
  System.out.println("----------");
  iraq.declare("来呀, 来互相伤害呀!!!");
 }
}