将交易细分为买/卖：

public class SellEvent extends TradeAccountEvent {public SellEvent(TradeAccount tradeAccount, double amount, Date tradExecutionTime) {super(tradeAccount, amount, tradExecutionTime, TradeType.SELL);}
}public class BuyEvent extends TradeAccountEvent {public BuyEvent(TradeAccount tradeAccount, double amount, Date tradExecutionTime) {super(tradeAccount, amount, tradExecutionTime, TradeType.BUY);}
}

处理类也区分

public class TradeSellAuditor {private List<SellEvent> sellEvents = Lists.newArrayList();public TradeSellAuditor(EventBus eventBus) {eventBus.register(this);}@Subscribepublic void auditSell(SellEvent sellEvent){sellEvents.add(sellEvent);System.out.println("Received SellEvent "+sellEvent);}public List<SellEvent> getSellEvents() {return sellEvents;}
}

public class TradeBuyAuditor {private List<BuyEvent> buyEvents = Lists.newArrayList();public TradeBuyAuditor(EventBus eventBus) {eventBus.register(this);}@Subscribepublic void auditBuy(BuyEvent buyEvent){buyEvents.add(buyEvent);System.out.println("Received TradeBuyEvent "+buyEvent);}public List<BuyEvent> getBuyEvents() {return buyEvents;}
}

发送事件区分类型

package bbejeck.guava.chapter7.publisher;import bbejeck.guava.chapter7.events.BuyEvent;
import bbejeck.guava.chapter7.events.SellEvent;
import bbejeck.guava.chapter7.events.TradeAccountEvent;
import bbejeck.guava.chapter7.events.TradeType;
import bbejeck.guava.common.model.TradeAccount;
import com.google.common.eventbus.EventBus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;import java.util.Date;/*** User: Bill Bejeck* Date: 4/26/13* Time: 11:29 AM*/
public class BuySellTradeExecutor {private EventBus eventBus;public BuySellTradeExecutor(EventBus eventBus) {this.eventBus = eventBus;}public void executeTrade(TradeAccount tradeAccount, double amount, TradeType tradeType) {TradeAccountEvent tradeAccountEvent = processTrade(tradeAccount, amount, tradeType);eventBus.post(tradeAccountEvent);}private TradeAccountEvent processTrade(TradeAccount tradeAccount, double amount, TradeType tradeType) {Date executionTime = new Date();String message = String.format("Processed trade for %s of amount %n type %s @ %s", tradeAccount, amount, tradeType, executionTime);TradeAccountEvent tradeAccountEvent;if (tradeType.equals(TradeType.BUY)) {tradeAccountEvent = new BuyEvent(tradeAccount, amount, executionTime);} else {tradeAccountEvent = new SellEvent(tradeAccount, amount, executionTime);}System.out.println(message);return tradeAccountEvent;}
}

测试示例

package bbejeck.guava.chapter7.subscriber;import bbejeck.guava.chapter7.EventBusTestBase;
import bbejeck.guava.chapter7.subscriber.complex.TradeBuyAuditor;
import bbejeck.guava.chapter7.subscriber.complex.TradeSellAuditor;
import com.google.common.eventbus.EventBus;
import org.junit.Before;
import org.junit.Test;import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;/*** User: Bill Bejeck* Date: 4/28/13* Time: 8:49 PM*/
public class TradeBuySellAuditorTest extends EventBusTestBase  {private TradeBuyAuditor buyAuditor;private TradeSellAuditor sellAuditor;private EventBus eventBus;@Beforepublic void setUp(){eventBus = getEventBus();buyAuditor = new TradeBuyAuditor(eventBus);sellAuditor = new TradeSellAuditor(eventBus);}@Testpublic void sellOnlyTest(){eventBus.post(sellEventBuilder().build());assertThat(sellAuditor.getSellEvents().size(),is(1));assertThat(buyAuditor.getBuyEvents().isEmpty(),is(true));}@Testpublic void buyOnlyTest(){eventBus.post(buyEventBuilder().build());assertThat(sellAuditor.getSellEvents().isEmpty(),is(true));assertThat(buyAuditor.getBuyEvents().size(),is(1));}
}