This sample demonstrates how Siddhi engine can be used with JMS event broker to receive, process and publish XML messages.
In this sample CEP will receive stock quote information and fire outputs if the last traded amount vary by 2 percent with regards to the average traded price within past 2 minutes.
from allStockQuotesStream#window.time(120000) insert into fastMovingStockQuotesStream symbol,avg(price) as avgPrice, price group by symbol having ((price > (avgPrice*1.02)) or ((avgPrice*0.98)>price ));
Here we will publish events using an JMS client to a JMS topic called AllStockQuotes and fired outputs of the bucket will be send to a JMS topic called FastMovingStockQuotes, which will be received using another JMS client and log in console.
Following is the configuration used in this sample.
Prerequisites
- Apache Ant to build & deploy the Sample & Service, and to run the client. Refer Installation Prerequisites for instructions to install Apache Ant.
Steps to configure the sample
The steps are as follows :
- Install the WSO2 Complex Event Processor, Refer to the Installation Guide for instructions.
- Now start the WSO2 Complex Event Processor. Refer to the Running the Product for instructions.
- Start WSO2 Message Broker with a port offset one (assuming setup is done on a single machine). Refer to the Running WSO2 MB for instructions.
- Then configure WSO2 Message Broker as the JMS Broker for CEP server as described in Using WSO2 MB as A JMS Broker for WSO2 CEP Server
- Copy the above bucket configuration to <CEP_HOME>/repository/deployment/server/cepbuckets folder. Note that we have used the JMS Broker "MBJmsBroker" created at step 4 in the bucket configuration.
- Now the bucket will be deployed at the CEP side. Please check the logs to verify.
Steps to run the sample
In order to run the above sample we have to do two things.
- Publish events to CEP server. We can do this by publishing events to the AllStockQuotes topic.
- Subscribe for events generated by CEP server according to the query we have defined in bucket configuration above. This can be done in two ways.
- Subscribe an JMS topic message subscriber to the topic FastMovingStockQuotes and get the events.
- Subscriber a web service client to the topic FastMovingStockQuotes and receive the events using a web service client instead of using a JMS client.
Publishing events to CEP server
We will use a JMS client for this purpose.
Following class will create Initial Context to run the event publisher client. Note that this class is used in event subscriber JMS client as well.
package org.wso2.cep.sample.jms.andes;
import javax.jms.TopicConnectionFactory;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import java.util.Properties;
public class JNDIContext {
public static final String QPID_ICF = "org.wso2.andes.jndi.PropertiesFileInitialContextFactory";
private static final String CF_NAME_PREFIX = "connectionfactory.";
private static final String CF_NAME = "ConnectionFactory";
private static final String userName = "admin";
private static final String password = "admin";
private static String CARBON_CLIENT_ID = "clientid";
private static String CARBON_VIRTUAL_HOST_NAME = "carbon";
private static String CARBON_DEFAULT_HOSTNAME = "localhost";
private static String CARBON_DEFAULT_PORT = "5673";
private InitialContext initContext = null;
private TopicConnectionFactory topicConnectionFactory = null;
public static JNDIContext instance = null;
private JNDIContext() {
createInitialContext();
createConnectionFactory();
}
public InitialContext getInitContext() {
return initContext;
}
public TopicConnectionFactory getTopicConnectionFactory() {
return topicConnectionFactory;
}
public static JNDIContext getInstance() {
if (instance == null) {
instance = new JNDIContext();
}
return instance;
}
/**
* Create Connection factory with initial context
*/
private void createConnectionFactory() {
try {
topicConnectionFactory = (TopicConnectionFactory) initContext.lookup("ConnectionFactory");
} catch (NamingException e) {
System.out.println("Can not create topic connection factory." + e);
}
}
/**
* Create Initial Context with given configuration
*/
private void createInitialContext() {
try {
Properties properties = new Properties();
properties.put(Context.INITIAL_CONTEXT_FACTORY, QPID_ICF);
properties.put(CF_NAME_PREFIX + CF_NAME, getTCPConnectionURL(userName, password));
System.out.println("TCPConnectionURL: = " + getTCPConnectionURL(userName, password));
initContext = new InitialContext(properties);
} catch (NamingException e) {
System.out.println("Can not create initial context with given parameters." + e);
}
}
public String getTCPConnectionURL(String username, String password) {
return new StringBuffer()
.append("amqp://").append(username).append(":").append(password)
.append("@").append(CARBON_CLIENT_ID)
.append("/").append(CARBON_VIRTUAL_HOST_NAME)
.append("?brokerlist='tcp://").append(CARBON_DEFAULT_HOSTNAME).append(":").append(CARBON_DEFAULT_PORT).append("'")
.toString();
}
}
Following class is the event publisher client. By running this class three events are generated and sent to the CEP server (Actually we publish events to the topic at WSO2 MB, which is registered at CEP server).
package org.wso2.cep.sample.jms.andes.xmlMessage;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.impl.builder.StAXOMBuilder;
import org.apache.axiom.om.util.StAXUtils;
import org.wso2.cep.sample.jms.andes.JNDIContext;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import javax.naming.InitialContext;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.ByteArrayInputStream;
public class AllStockQuotesPublisher {
private static InitialContext initContext = null;
private static TopicConnectionFactory topicConnectionFactory = null;
public static void main(String[] args) throws XMLStreamException {
String xmlElement1 = "<quotedata:AllStockQuoteStream xmlns:quotedata=\"http://ws.cdyne.com/\">\n" +
" <quotedata:StockQuoteEvent>\n" +
" <quotedata:StockSymbol>MSFT</quotedata:StockSymbol>\n" +
" <quotedata:LastTradeAmount>126.36 </quotedata:LastTradeAmount>\n" +
" <quotedata:StockChange>0.05</quotedata:StockChange>\n" +
" <quotedata:OpenAmount>25.05</quotedata:OpenAmount>\n" +
" <quotedata:DayHigh>25.46</quotedata:DayHigh>\n" +
" <quotedata:DayLow>25.01</quotedata:DayLow>\n" +
" <quotedata:StockVolume>20452658</quotedata:StockVolume>\n" +
" <quotedata:PrevCls>25.31</quotedata:PrevCls>\n" +
" <quotedata:ChangePercent>0.20</quotedata:ChangePercent>\n" +
" <quotedata:FiftyTwoWeekRange>22.73 - 31.58</quotedata:FiftyTwoWeekRange>\n" +
" <quotedata:EarnPerShare>2.326</quotedata:EarnPerShare>\n" +
" <quotedata:PE>10.88</quotedata:PE>\n" +
" <quotedata:CompanyName>Microsoft Corpora</quotedata:CompanyName>\n" +
" <quotedata:QuoteError>false</quotedata:QuoteError>\n" +
" </quotedata:StockQuoteEvent>\n" +
" </quotedata:AllStockQuoteStream>";
String xmlElement2 = "<quotedata:AllStockQuoteStream xmlns:quotedata=\"http://ws.cdyne.com/\">\n" +
" <quotedata:StockQuoteEvent>\n" +
" <quotedata:StockSymbol>MSFT</quotedata:StockSymbol>\n" +
" <quotedata:LastTradeAmount>36.36</quotedata:LastTradeAmount>\n" +
" <quotedata:StockChange>0.05</quotedata:StockChange>\n" +
" <quotedata:OpenAmount>25.05</quotedata:OpenAmount>\n" +
" <quotedata:DayHigh>25.46</quotedata:DayHigh>\n" +
" <quotedata:DayLow>25.01</quotedata:DayLow>\n" +
" <quotedata:StockVolume>20452658</quotedata:StockVolume>\n" +
" <quotedata:PrevCls>25.31</quotedata:PrevCls>\n" +
" <quotedata:ChangePercent>0.20</quotedata:ChangePercent>\n" +
" <quotedata:FiftyTwoWeekRange>22.73 - 31.58</quotedata:FiftyTwoWeekRange>\n" +
" <quotedata:EarnPerShare>2.326</quotedata:EarnPerShare>\n" +
" <quotedata:PE>10.88</quotedata:PE>\n" +
" <quotedata:CompanyName>Microsoft Corpora</quotedata:CompanyName>\n" +
" <quotedata:QuoteError>false</quotedata:QuoteError>\n" +
" </quotedata:StockQuoteEvent>\n" +
" </quotedata:AllStockQuoteStream>";
String xmlElement3 = "<quotedata:AllStockQuoteStream xmlns:quotedata=\"http://ws.cdyne.com/\">\n" +
" <quotedata:StockQuoteEvent>\n" +
" <quotedata:StockSymbol>MSFT</quotedata:StockSymbol>\n" +
" <quotedata:LastTradeAmount>6.36</quotedata:LastTradeAmount>\n" +
" <quotedata:StockChange>0.05</quotedata:StockChange>\n" +
" <quotedata:OpenAmount>25.05</quotedata:OpenAmount>\n" +
" <quotedata:DayHigh>25.46</quotedata:DayHigh>\n" +
" <quotedata:DayLow>25.01</quotedata:DayLow>\n" +
" <quotedata:StockVolume>20452658</quotedata:StockVolume>\n" +
" <quotedata:PrevCls>25.31</quotedata:PrevCls>\n" +
" <quotedata:ChangePercent>0.20</quotedata:ChangePercent>\n" +
" <quotedata:FiftyTwoWeekRange>22.73 - 31.58</quotedata:FiftyTwoWeekRange>\n" +
" <quotedata:EarnPerShare>2.326</quotedata:EarnPerShare>\n" +
" <quotedata:PE>10.88</quotedata:PE>\n" +
" <quotedata:CompanyName>Microsoft Corpora</quotedata:CompanyName>\n" +
" <quotedata:QuoteError>false</quotedata:QuoteError>\n" +
" </quotedata:StockQuoteEvent>\n" +
" </quotedata:AllStockQuoteStream>";
initContext = JNDIContext.getInstance().getInitContext();
topicConnectionFactory = JNDIContext.getInstance().getTopicConnectionFactory();
AllStockQuotesPublisher publisher = new AllStockQuotesPublisher();
XMLStreamReader reader1 = StAXUtils.createXMLStreamReader(new ByteArrayInputStream(
xmlElement1.getBytes()));
StAXOMBuilder builder1 = new StAXOMBuilder(reader1);
OMElement OMMessage1 = builder1.getDocumentElement();
publisher.publish("AllStockQuotes", OMMessage1);
XMLStreamReader reader2 = StAXUtils.createXMLStreamReader(new ByteArrayInputStream(
xmlElement2.getBytes()));
StAXOMBuilder builder2 = new StAXOMBuilder(reader2);
OMElement OMMessage2 = builder2.getDocumentElement();
publisher.publish("AllStockQuotes", OMMessage2);
XMLStreamReader reader3 = StAXUtils.createXMLStreamReader(new ByteArrayInputStream(
xmlElement3.getBytes()));
StAXOMBuilder builder3 = new StAXOMBuilder(reader3);
OMElement OMMessage3 = builder3.getDocumentElement();
publisher.publish("AllStockQuotes", OMMessage3);
}
/**
* Publish message to given topic
*
* @param topicName - topic name to publish messages
* @param message - message to send
*/
public void publish(String topicName, OMElement message) {
// create topic connection
TopicConnection topicConnection = null;
try {
topicConnection = topicConnectionFactory.createTopicConnection();
topicConnection.start();
} catch (JMSException e) {
System.out.println("Can not create topic connection." + e);
return;
}
// create session, producer, message and send message to given destination(topic)
// OMElement message text is published here.
Session session = null;
try {
session = topicConnection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic(topicName);
MessageProducer producer = session.createProducer(topic);
TextMessage jmsMessage = session.createTextMessage(message.toString());
producer.send(jmsMessage);
producer.close();
session.close();
topicConnection.stop();
topicConnection.close();
} catch (JMSException e) {
System.out.println("Can not subscribe." + e);
}
}
}
Subscribing for filtered events and notifications from CEP server
a. Using a JMS client receiver
Following class acts as a JMS topic subscriber client. We register a subscription for filtered events we get from CEP triggered according to the query at bucket we have defined (Actually we are subscribing for a topic created at WSO2 Message broker, to which CEP will publish filtered events and notifications internally).
package org.wso2.cep.sample.jms.andes.xmlMessage;
import org.wso2.cep.sample.jms.andes.JNDIContext;
import javax.jms.JMSException;
import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import javax.jms.TopicSession;
import javax.jms.TopicSubscriber;
import javax.naming.InitialContext;
import javax.xml.stream.XMLStreamException;
import java.util.Enumeration;
public class FastMovingStockQuotesSubscriber implements MessageListener {
private static InitialContext initContext = null;
private static TopicConnectionFactory topicConnectionFactory = null;
private boolean messageReceived = false;
static String TOPIC = "FastMovingStockQuotes";
public static void main(String[] args) throws XMLStreamException {
initContext = JNDIContext.getInstance().getInitContext();
topicConnectionFactory = JNDIContext.getInstance().getTopicConnectionFactory();
new FastMovingStockQuotesSubscriber().subscribe(TOPIC);
}
public void subscribe(String topicName) {
// create connection
TopicConnection topicConnection = null;
try {
topicConnection = topicConnectionFactory.createTopicConnection();
} catch (JMSException e) {
System.out.println("Can not create topic connection." + e);
return;
}
// create session, subscriber, message listener and listen on that topic
TopicSession session = null;
try {
session = topicConnection.createTopicSession(false, javax.jms.Session.AUTO_ACKNOWLEDGE);
Topic topic = session.createTopic(topicName);
TopicSubscriber subscriber = session.createSubscriber(topic);
subscriber.setMessageListener(this);
topicConnection.start();
synchronized (this) {
while (!messageReceived) {
try {
this.wait();
} catch (InterruptedException e) {
}
}
}
} catch (JMSException e) {
System.out.println("Can not subscribe." + e);
}
}
public void onMessage(Message message) {
if (message instanceof TextMessage) {
TextMessage textMessage = (TextMessage) message;
try {
System.out.println("output = " + textMessage.getText());
synchronized (this) {
messageReceived = true;
}
} catch (JMSException e) {
System.out.println("error at getting text out of received message. = " + e);
}
} else if (message instanceof MapMessage) {
try {
Enumeration enumeration = ((MapMessage) message).getMapNames();
for (; enumeration.hasMoreElements(); ) {
System.out.println(((MapMessage) message).getString((String) enumeration.nextElement()));
}
} catch (JMSException e) {
e.printStackTrace();
}
} else {
System.out.println("Received message is not a text/map message.");
}
}
}
b. Using a web service message receiver
Deploying receiver service
First we have to deploy a web service at any WSO2 Server which would act as the receiver web service for messages from CEP server. We will use CEP itself to deploy such a web service.
The steps are as follows :
- In a command prompt, switch to the FastMovingStockQuoteReceiverService services directory: <CEP_HOME>/ samples/services/FastMovingStockQuoteReceiverService
For example, in Linux: cd <CEP_HOME> /samples/services/FastMovingStockQuoteReceiverService - From there, type ant, this will deploy the FastMovingStockQuoteReceiverService in CEP itself.
You can follow the server logs to check whether FastMovingStockQuoteReceiverService.arr has been properly deployed.
You will also be able to see the axis2 service in the services list.
Configuring receiver service
We need to Configure the FastMovingStockQuoteReceiverService in order to receive the output events emitted by the bucket under the FastMovingStockQuotes topic. Here we will be creating FastMovingStockQuotes topic in the WSO2 Message Broker and subscribe FastMovingStockQuoteReceiverService on that topic.
The steps are as follows :
- Sign In. Enter your user name and password to log on to the Message Broker Management Console.
- Click on "Add" menu item under "Topics" Menu in Manage section of the left panel
- Specify the topic name in the topic input text box, in this case topic name is : "FastMovingStockQuotes" (the output topic) and click on 'Add Topic' button. This will add the topic to the server and you will be directed to the Topic Browser page.
- Once you click on the topic in topic browser page you will be able see four links as in the bellow image. Click in the subscribe link and you will be directed to Subscribe page.
Create subscription with following details. Once you are done click the Subscribe button.
topic : FastMovingStockQuotes (Output topic) subscription mode: Topic only subscription URL : http://localhost:9763/services/FastMovingStockQuoteService/getOMElement expiration Time : select a future date from calender
Once you click on the "Subscribe" button, you will be directed to the Topic Browser page.
You can verify whether you have correctly subscribe to the topic by clicking on "Details" link of that topic in topic browser page.
Once you click on that, you will be directed to the "topic details" page and there you will find all the subscriptions for that topic and its children (in this case it does not exists) and permission on that topic. Apart from that with the publish section, you can publish a test XML message to that topic and check whether your subscription URL has been properly subscribed.
Running the Samples
The steps are as follows :
- If you are using JMS subscriber client i.e "Using a JMS Client Receiver", build and run the topic subscriber class provided above. Else if you are using the "Web Service Message Receiver" above configurations under section (b) is enough.
- Run the JMS publisher client.
- It can be noticed that CEP analyzes the events we have published and fire outputs if the last traded amount vary by 2 percent with regards to the average traded price within past 2 minutes.
Observation
Observe the console where we are running the JMS subscriber client or server console where message receiving web service is deployed. You will see some logs like below.