JBoss ESB学习笔记11——第十个ESB应用Message Filters

续上篇介绍了第九个ESB应用，本文介绍第十个ESB应用——Message Filters。

 

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1 概述
本实例主要演示了如何设置基于内容的过滤器。这里通过客户端发送Order对象到ESB，在处理消息之前，过滤器将根据Order对象的quantity属性进行过滤，当该属性的值大于10时，消息将被传送到NextService服务进行处理，否则，该消息将会被过滤掉不做任何处理。

 

2 新建ESB工程
操作过程略。

 

3 ESB配置
3.1 创建消息队列和消息主题

<?xml version="1.0" encoding="UTF-8"?>
<server>
	<mbean code="org.jboss.jms.server.destination.QueueService"		name="jboss.esb.quickstart.destination:service=Queue,name=messagefilterRequestEsb" 	xmbean-dd="xmdesc/Queue-xmbean.xml">
		<depends optional-attribute-name="ServerPeer">
jboss.messaging:service=ServerPeer
		</depends>
		<depends>jboss.messaging:service=PostOffice</depends>
	</mbean>
	<mbean code="org.jboss.jms.server.destination.QueueService"		name="jboss.esb.quickstart.destination:service=Queue,name=messagefilterRequestGw" xmbean-dd="xmdesc/Queue-xmbean.xml">
		<depends optional-attribute-name="ServerPeer">
jboss.messaging:service=ServerPeer
		</depends>
		<depends>jboss.messaging:service=PostOffice</depends>
	</mbean>
	<mbean code="org.jboss.jms.server.destination.QueueService"		name="jboss.esb.quickstart.destination:service=Queue,name=messagefilterNextRequestEsb" xmbean-dd="xmdesc/Queue-xmbean.xml">
		<depends optional-attribute-name="ServerPeer">
jboss.messaging:service=ServerPeer
		</depends>
		<depends>jboss.messaging:service=PostOffice</depends>
	</mbean>
</server>

 

3.2 定义Provider
这里将定义一个JMS Provider，并定义3个消息通道，内容如下：

<jms-provider connection-factory="ConnectionFactory"
name="JBossMessaging">
	<jms-bus busid="gwChanel">
		<jms-message-filter dest-name="queue/messagefilterRequestGw"
			dest-type="QUEUE" />
	</jms-bus>
	<jms-bus busid="esbChanel">
		<jms-message-filter dest-name="queue/messagefilterRequestEsb"
			dest-type="QUEUE" />
	</jms-bus>
	<jms-bus busid="nextEsbChanel">
		<jms-message-filter dest-type="QUEUE"
dest-name="queue/messagefilterNextRequestEsb" />
	</jms-bus>
</jms-provider>

 

3.3 定义第一个Service

<service category="MessageFilter" description="Message Filter"
name="MessageFilterService">
	<listeners />
	<actions mep="OneWay">
		<action />
	</actions>
</service>

 

3.3.1 定义Listener

<listeners>
	<jms-listener busidref="gwChanel" is-gateway="true"
		name="gwListener" />
	<jms-listener busidref="esbChanel" name="esbListener" />
</listeners>

 

3.3.2 定义Action

<actions mep="OneWay">
	<action class="org.jboss.soa.esb.actions.MessageFilter"
name="MessageFilter">
		<property name="ruleSet" value="FilterRules.drl" />
		<property name="ruleReload" value="true" />
		<property name="destinations">
			<route-to destination-name="DemoDestination"
				service-category="Test" service-name="NextService" />
		</property>
		<property name="object-paths">
			<object-path
esb="body.'org.jboss.soa.esb.message.defaultEntry'" />
		</property>
	</action>
</actions>

配置说明：这里定义了一个消息过滤器，过滤规则在文件FilterRules.drl中进行定义。当满足规则的消息到来时，将会通过过滤器而被传送到NextService服务进行处理，否则，消息将会被直接过滤掉而不做任何处理。

 

3.3.3 定义过滤规则
在src目录下创建FilterRules.drl文件，并定义如下规则脚本：

#created on: Oct 30, 2006
package com.jboss.soa.esb.routing.cbr

#list any import classes here.
import org.jboss.soa.esb.message.Message;
import org.jboss.soa.esb.message.format.MessageType;
import com.thu.afa.esb.jbossesb.client.bean.Order;

#declare any global variables here
global java.util.List destinations;

rule "Pricing Rule - over threshold"
	
	when
	    m     : Message ()
		order : Order( quantity >= 10)
	then
		System.out.println(order.getQuantity() + " Makes the threshold");
		#we can modify the object
		order.setDiscount(10);
		#demonstrate that we can add a new object to the message
		m.getBody().add("DiscountObject","10%");
		destinations.add("DemoDestination");
end
		
rule "Pricing Rule - under threshold"

	#adding this for debug output, the important part is to *NOT* set a destination
	when
	    m     : Message ()
		order : Order( quantity < 10)
	then
		System.out.println(order.getQuantity() + " Does not make the threshold");
		order.setDiscount(0);
end

 

3.3.4 定义Order类

package com.thu.afa.esb.jbossesb.client.bean;

import java.io.Serializable;
import java.math.BigDecimal;

public class Order implements Serializable
{
    private static final long serialVersionUID = 1L;
    private int quantity;
    private BigDecimal unitPrice;
    private double discount;
    private BigDecimal totalPrice;
    
    // setters and getters
}

 

3.5 定义第二个Service

<service category="Test" description="Demo Destination"
name="NextService">
	<listeners>
		<jms-listener busidref="nextEsbChanel" name="esbChanel" />
	</listeners>
	<actions mep="OneWay">
		<action class="org.jboss.soa.esb.actions.Notifier"
name="notificationAction">
			<property name="okMethod" value="notifyOK" />
			<property name="destinations">
				<NotificationList type="OK">
					<target class="NotifyConsole" />
				</NotificationList>
			</property>
		</action>
	</actions>
</service>

 

3.6 配置部署文件
部署依赖文件deployment.xml内容如下：

<jbossesb-deployment>
	<depends>jboss.esb:deployment=jbrules.esb</depends>
	<depends>jboss.esb.quickstart.destination:service=Queue,name=messagefilterRequestEsb
	</depends>
	<depends>jboss.esb.quickstart.destination:service=Queue,name=messagefilterRequestGw
	</depends>
	<depends>jboss.esb.quickstart.destination:service=Queue,name=messagefilterNextRequestEsb
	</depends>
</jbossesb-deployment>

 

3.7 部署ESB
将整个工程导出成一个ESB文件，并保存至JBoss ESB Server的部署目录下，启动JBoss ESB Server即可

4 ESB客户端
4.1 新建Java工程
这里略去操作过程以及添加所需要的Jar包，具体操作过程可参考第一个ESB实例说明。

4.2 发送消息的客户端

/***********************************************************************
 * <p>Project Name: helloworldclient</p>
 * <p>File Name: com.thu.afa.esb.jbossesb.client.MessageFilterClient.java</p>
 * <p>Copyright: Copyright (c) 2010</p>
 * <p>Company: <a href="http://afa.thu.com">http://afa.thu.com</a></p>
 ***********************************************************************/
package com.thu.afa.esb.jbossesb.client;

import java.io.Serializable;
import java.util.Properties;

import javax.jms.ObjectMessage;
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.naming.Context;
import javax.naming.InitialContext;

import com.thu.afa.esb.jbossesb.client.bean.Order;

/**
 * <p>Class Name: MessageFilterClient</p>
 * <p>Description: </p>
 * @author Afa
 * @date 2010-9-14
 * @version 1.0
 */
public class MessageFilterClient
{
	private QueueConnection connection;
	private QueueSession session;
	private Queue queue;
	
	public void setupConnection() throws Exception
	{
		Properties properties = new Properties();
		properties.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");   
		properties.put(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");   
		properties.put(Context.PROVIDER_URL, "jnp://127.0.0.1:1099");
		InitialContext context = new InitialContext(properties);
		
		QueueConnectionFactory factory = (QueueConnectionFactory) context.lookup("ConnectionFactory");
		connection = factory.createQueueConnection();
		queue = (Queue) context.lookup("queue/messagefilterRequestGw");
		session = connection.createQueueSession(false, QueueSession.AUTO_ACKNOWLEDGE);
		connection.start();
		
		System.out.println("Connection Started");
	}
	
	public void stop() throws Exception
	{
		if(connection != null) connection.stop();
		if(session != null) session.close();
		if(connection != null) connection.close();
	}
	
	public void sendAMessage(Serializable object) throws Exception
	{
		QueueSender sender = session.createSender(queue);
		ObjectMessage message = session.createObjectMessage(object);
		sender.send(message);
		sender.close();
	}

	/**
	 * <p>Title: </p>
	 * <p>Method Name: main</p>
	 * <p>Description: </p>
	 * @author: Afa
	 * @date: 2010-9-14
	 * @param args
	 */
	public static void main(String[] args) throws Exception
	{
		Order order = new Order();
		order.setQuantity(5);
		MessageFilterClient client = new MessageFilterClient();
		client.setupConnection();
		client.sendAMessage(order);
		client.stop();
	}

}

 

运行客户端程序即可看到以下输出结果，下图是分别将quantity属性设置为15和5的输出结果。

  

 

4.3 注意事项
在客户端和服务端的classpath中都必须能找到Order类，其中，类名和包路径也都必须完全一致，而且需要与规则文件中的导入信息保持一致，否则，将会出现如下异常：
No ClassLoaders found for: com.thu.afa.esb.jbossesb.client.bean.Order

 

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Afa
Mar 29th, 2011
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