Java设计模式的中介者模式是行为模式之一。定义一个中介对象来封装系列对象之间的交互。中介者使各个对象不需要显式地相互引用，从而使其耦合性松散，并且可以独立地改变他们之间的交互。
如下图所示：
生产者、消费者、代理商之间的中介模式实例：
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public abstract class PersonColleague
{
protected Mediator mediator;
public Mediator getMediator()
{
return mediator;
}
public void setMediator(final Mediator mediator)
{
this.mediator = mediator;
}
protected abstract void message(String context);
}
public class Mediator
{
private PersonColleague consumer = null;
private ProducerColleague producer = null;
public ProducerColleague getProducer()
{
return producer;
}
public void setProducer(final ProducerColleague producer)
{
this.producer = producer;
}
public PersonColleague getConsumer()
{
return consumer;
}
public void setConsumer(final PersonColleague consumer)
{
this.consumer = consumer;
}
public Mediator()
{
}
public synchronized void message(final String context)
{
if (consumer != null)
{
System.out.println(context);
}
else if (producer != null)
{
System.out.println(context);
}
}
}
public class ConsumerColleague extends PersonColleague
{
public ConsumerColleague(final Mediator mediator)
{
this.mediator = mediator;
}
@Override
protected void message(final String context)
{
this.mediator.setConsumer(this);
this.mediator.message("hello! i am a consumer");
}
}
public class ProducerColleague extends PersonColleague
{
public ProducerColleague(final Mediator mediator)
{
this.mediator = mediator;
}
@Override
protected void message(final String context)
{
this.mediator.setProducer(this);
this.mediator.message(context);
}
}
public class Client
{
public static void main(final String[] args)
{
final Mediator mediator = new Mediator();
final PersonColleague person = new ConsumerColleague(mediator);
final PersonColleague person1 = new ProducerColleague(mediator);
person.message("I am a consumer");
person1.message("I am a producer");
}
}
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运行结果：
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2
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hello! i am a consumer
I am a producer
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