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" ); } } |
运行结果:
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hello! i am a consumer I am a producer |