Java File Formatting using Maven via Eclipse settings

Hi,

In below blog I am demonstrating an example of maven java formater, for java files. 

PROBLEM TAKEN

In my recent project multiple teams is working on a code base and most of them are fresher/associate level engineers.  Obviously they are not much aware of code standards and best practices to be followed while writing a code.  Check-style is one of the plugin comes with maven to cross check your code against all such standards to aware you about coding standards.

Few suggestions that checkstyle plugins imposes is:

• Apply correct indentation (biggest plus point)
• Lines should be wrapped after 80 characters
• File must be UTF encoding
• Tab characters in file must be replaced with spaces
• And so on….

Although one can perform such all formatting using eclipse but when files are large in number and this happens repeatedly, it’s hard to maintain such coding standards.

TECHNOLOGY STACK USED

• Eclipse Juno
• Java
• Maven

SOLUTION APPROACH

The project is divided into multiple modules.  There is inter-dependency among maven sub-projects.  I made a change to parent most pom file structure for java file formatting so that all child and dependent project files get formatted as per the configuration file.

Configuration file!! What’s that??

Well, the goal here is to format all the project java files to meet most of the checkstyle rules/standards.  Most of the!! Yes, all the rules cannot be sufficed suggested by checkstyle as there are logical rules as well like making a method final etc.  All such rules require manual intervention.

Ok, so the very first step that you need to perform is open eclipse IDE.  Go to “Window -> Preferences”.  In the text box on top left type “format”.  A filtering would be applied; from available options select “Java -> Code Style -> Formatter” option.  Here you will find active profiles on right hand side screen like Java Conventions, Eclipse etc. 

Either selects one of those you want or create a new one using “New” option.  After that select “Edit option” and apply rules you want; such as converting tab character to 4 spaces etc.  See image below.

After making all desired changes as per your project structure and need, select “Apply” and using “Export” option save your present profile into XML file say for example you save it at location “C:/my-profile.xml”.

CHANGES TO POM

Now use this profile XML to format java files using maven.  Here we go.  Add java formatter plugin to your parent most pom.xml.

...

 <build>

    <plugins>

        <plugin>

            <groupId>com.googlecode.maven-java-formatter-plugin</groupId>

            <artifactId>maven-java-formatter-plugin</artifactId>

            <version>0.3.1</version>

            <configuration>

                <lineEnding>LF</lineEnding>

                <encoding>UTF-8</encoding>

                <configFile>C:/my-profile.xml</configFile>

            </configuration>

        </plugin>

        … other plugins …

    </plugins>

</build>

...

Now the maven command that you need to perform this operation is:

mvn java-formatter:format

And it’s done. 

You can find more details here about plugin.

Thanks

Shailendra

Example of Spring, ActiveMQ to send Email

---

Hi,


I decided to write this blog because I could not find one simple example in combination to Spring, ActiveMQ and Email the message from queue.


Problem taken

What I am going to do in this example is:

1. Create one Spring application, that has one POJO i.e. Entity, I took Mobile as my pojo with three attributes as Company, Model and Price.
2. There will be one message producer which will post one message (as entity Mobile) to queue-one.
3. There will be a listener to queue-one and on receiving a message it will de-queue the message.  Further after processing Listener post message to queue-two.
4. This queue-two has another listener which de-queue the message from queue-two and process it to send a mail. 

Pictorial Presentation

Technologies Used

Below is the stack of technologies

• Spring 3
• ActiveMQ 5.6.0
• Java Mail
• Tomcat 7
• Maven

How to execute and flow explanation

1. You need to hit url http://host:port/app/main/amqmobile/form.html
2. Based on given configuration this url will search for file form.jsp inside "WEB-INF/amqmobile" folder in your web application.
3. As this is a GET request method in getForm of AMQMobileController will be executed.
4. From getForm method AMQMsgProducer.produce method will be called that in turn creates 
• AMQMobile object
• Convert it into ObjectMessage
• Send it to queue-one namely "amqMobileQueue"
5. As soon as the message send to "amqMobileQueue", listener 1 i.e. AMQMobileListener will get active and its method onMessage will be executed.
6. This is the place to perform biz logic. Now that message is send to AMQMsgSender.sendMessage method.  This method sends the message to queue-two i.e. amqMobileEmailQueue.
7. Now Listener 2 i.e. AMQMobileEmailListener will act and its method onMessage sends the email.

Config File - applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:intg="http://www.springframework.org/schema/integration"
       xmlns:jms="http://www.springframework.org/schema/integration/jms"
       xmlns:mail="http://www.springframework.org/schema/integration/mail"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/integration
http://www.springframework.org/schema/integration/spring-integration-2.1.xsd
        http://www.springframework.org/schema/integration/mail
        http://www.springframework.org/schema/integration/mail/spring-integration-mail-2.1.xsd">
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl"
          p:host="domain-address"
          p:port="587"
          p:username="username"
          p:password="password"
            >
        <property name="javaMailProperties">
            <props>
                <prop key="mail.smtp.auth">true</prop>
                <prop key="mail.smtp.starttls.enable">true</prop>
                <prop key="mail.smtp.auth.ntlm.domain" >DOMAIN</prop>
            </props>
        </property>
    </bean>


<bean id="reqAMQMobileQueue" class="org.apache.activemq.command.ActiveMQQueue">
        <property name="physicalName" value="amqMobileQueue" />
    </bean>

    <bean id="reqAMQMobileEmailQueue" class="org.apache.activemq.command.ActiveMQQueue">
        <property name="physicalName" value="amqMobileEmailQueue" />
    </bean>

    <bean id="activeMQConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
        <property name="brokerURL" value="tcp://localhost:61616" />
    </bean>

    <bean id="amqMobileListener" class="com.examples.amqmobile.AMQMobileListener" />

    <bean id="container" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
        <property name="connectionFactory" ref ="activeMQConnectionFactory" />
        <property name="destination" ref ="reqAMQMobileQueue"/>
        <property name="messageListener" ref ="amqMobileListener"/>
        <property name="concurrentConsumers" value="1" />
    </bean>

    <bean id="amqMobileEmailListener" class="com.examples.amqmobile.AMQMobileEmailListener" />
    <bean id="emailContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
        <property name="connectionFactory" ref ="activeMQConnectionFactory" />
        <property name="destination" ref ="reqAMQMobileEmailQueue"/>
        <property name="messageListener" ref ="amqMobileEmailListener"/>
        <property name="concurrentConsumers" value="1" />
    </bean>

    <bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
        <property name="connectionFactory" ref="activeMQConnectionFactory" />
        <property name="defaultDestination" ref="reqAMQMobileQueue" />
    </bean>
</beans>



Config File - main-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:context="http://www.springframework.org/schema/context"

       xmlns:p="http://www.springframework.org/schema/p"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    <context:component-scan base-package="com" />

    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" />

</beans>

Config File - web.xml

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         id="WebApp_ID" version="2.5">

    <display-name>Spring examples</display-name>
    <description>Spring examples</description>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/classes/applicationContext.xml
        </param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <servlet>
        <servlet-name>main</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>main</servlet-name>
        <url-pattern>/main/*</url-pattern>
    </servlet-mapping>
</web-app>

JSP File - form.jsp (to be placed inside WEB-INF/amqmobile folder)
// This file does not contains any logic, it is just a hook point to controller

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>

<html>
<head>
<title>Create AMQMobile</title>
</head>
<body>

<h1>Create AMQMobile</h1>

<p><b>You have successfully created a amqmobile.</b></p>

</body>
</html>

Java File - AMQMobile.java

package com.examples.amqmobile;

import java.io.Serializable;

/**
 * Created with IntelliJ IDEA.
 * User: sverma
 * Date: 18/10/12
 * Time: 3:06 PM
 */
public class AMQMobile implements Serializable {

    private String company;
    private String model;
    private int price;

    public String getCompany() {
        return company;
    }

    public void setCompany(String company) {
        this.company = company;
    }

    public String getModel() {
        return model;
    }

    public void setModel(String model) {
        this.model = model;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public String toString () {
        StringBuilder sb = new StringBuilder().append("Company: ").append(company)
                                  .append(", Model: ").append(model)
                                  .append(", Price: ").append(price);
        return sb.toString();
    }

}

Java File - AMQMsgProducer.java

package com.examples.amqmobile;

import org.apache.activemq.command.ActiveMQQueue;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.jms.core.JmsTemplate;

import org.springframework.jms.core.MessageCreator;

import org.springframework.stereotype.Service;

import javax.jms.*;

/**

 * Created with IntelliJ IDEA.

 * User: sverma

 * Date: 5/12/12

 * Time: 10:59 AM

 */

@Service("amqMsgProducer")

public class AMQMsgProducer {

    @Autowired

    JmsTemplate jmsTemplate;

    public void produce() {

        jmsTemplate.send(new MessageCreator() {

            public Message createMessage(Session session) throws JMSException {

                AMQMobile amqMobile = new AMQMobile();

                amqMobile.setCompany("newCompany");

                amqMobile.setModel("iPhone5");

                amqMobile.setPrice(45000);

                ObjectMessage message = session.createObjectMessage(amqMobile);

                System.out.println("Sending on ["+jmsTemplate.getDefaultDestination()+"] object as " + amqMobile);

                return message;

            }

        });

    }

}

Java File - AMQMobileListener.java

package com.examples.amqmobile;

import org.apache.activemq.command.ActiveMQObjectMessage;

import org.springframework.beans.factory.annotation.Autowired;

import javax.jms.JMSException;

import javax.jms.Message;

import javax.jms.MessageListener;

/**

 * Created with IntelliJ IDEA.

 * User: sverma

 * Date: 4/12/12

 * Time: 5:18 PM

 */

public class AMQMobileListener implements MessageListener {

    @Autowired

    AMQMsgSender amqMsgSender;

    public void onMessage(Message message) {

        System.out.println("OnMessage: Listener working... " + message);

        System.out.println("OnMessage: message instance matched = " + (message instanceof ActiveMQObjectMessage));

        if (message instanceof ActiveMQObjectMessage)

        {

            try

            {

                System.out.println("Converting object to AMQMobile class.");

                AMQMobile amqMobile = (AMQMobile) ((ActiveMQObjectMessage) message).getObject();

                System.out.println("OnMessage: Object received in Listener as " + amqMobile);

                /* call message sender to put message onto second queue */

                amqMsgSender.sendMessage(amqMobile);

            }

            catch (Exception e)

            {

                e.printStackTrace();

            }

        }

    }

}

Java File - AMQMsgSender.java

package com.examples.amqmobile;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.jms.core.JmsTemplate;

import org.springframework.stereotype.Service;

import javax.jms.JMSException;

import javax.jms.Queue;

/**

 * Created with IntelliJ IDEA.

 * User: sverma

 * Date: 4/12/12

 * Time: 5:21 PM

 */

@Service ("amqMsgSender")

public class AMQMsgSender {

    @Autowired

    private JmsTemplate jmsTemplate;

    @Autowired

    private Queue reqAMQMobileEmailQueue;

    /**

     * Sends message using JMS Template.

     *

     *

     * @param msg the msg

     * @throws JMSException the jMS exception

     */

    public void sendMessage(AMQMobile msg) throws JMSException

    {

        System.out.println("About to put message on queue. Queue[" + reqAMQMobileEmailQueue.toString() + "] Message[" + msg + "]");

        jmsTemplate.convertAndSend(reqAMQMobileEmailQueue, msg);

    }

    /**

     * Sets the jms template.

     *

     * @param template the jms template

     */

    public void setJmsTemplate(JmsTemplate template)

    {

        this.jmsTemplate = template;

    }

}

File - AMQMobileEmailListener.java

package com.examples.amqmobile;

import org.apache.activemq.command.ActiveMQObjectMessage;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.mail.MailSender;

import org.springframework.mail.SimpleMailMessage;

import javax.jms.Message;

import javax.jms.MessageListener;

import java.util.Date;

/**

 * Created with IntelliJ IDEA.

 * User: sverma

 * Date: 4/12/12

 * Time: 5:18 PM

 */

public class AMQMobileEmailListener implements MessageListener {

    @Autowired

    MailSender mailSender;

    public void onMessage(Message message) {

        System.out.println("OnMessage: Email Listener working... " + message);

        System.out.println("OnMessage: Email message instance matched = " + (message instanceof ActiveMQObjectMessage));

        if (message instanceof ActiveMQObjectMessage)

        {

            try

            {

                System.out.println("Converting object to AMQMobile class for email.");

                AMQMobile amqMobile = (AMQMobile) ((ActiveMQObjectMessage) message).getObject();

                System.out.println("OnMessage: Email Object received in Listener as " + amqMobile);

                /* call message sender to put message onto second queue */

                System.out.println("Sending mail for amqMobile " + amqMobile);

                SimpleMailMessage msg = new SimpleMailMessage();

                msg.setTo("sverma@impetus.co.in");

                msg.setFrom("sverma@impetus.co.in");

                msg.setSubject("Transforming from activemq");

                msg.setSentDate(new Date());

                msg.setText("Transforming using spring for mobile " + amqMobile);

                System.out.println("Waiting for 10 sec intentionally bf sending mail...");

                Thread.sleep(10000); // Mail server was throwing error of message sending limit in given time frame exceeds

                mailSender.send(msg);

            }

            catch (Exception e)

            {

                e.printStackTrace();

            }

        }

    }

}

Java File - AMQMobileController.java

package com.examples.amqmobile;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

/**

 * Created with IntelliJ IDEA.

 * User: sverma

 * Date: 18/10/12

 * Time: 7:38 PM

 */

@Controller

public class AMQMobileController {

    @Autowired

    AMQMsgProducer amqMsgProducer;

    @RequestMapping (value = "/amqmobile/form.html", method = RequestMethod.GET)

    public void getForm(Model model) {

        System.out.println("AMQController: Adding amq mobile in a model");

        amqMsgProducer.produce();

        System.out.println("AMQController: Msg send");

    }

}

Although I tried to keep my logic focus, but definitely I need to work more on formatting skills :)

I am skipping other information like maven entries etc. Please do let me know if you want any help on above.

Above Code is at GitHub, click here.


- Shailendra Verma

---

Note: I tested this application; after commenting Thread.sleep and mail.send command to save mailbox; with jMeter for 5000 simultaneous threads and there is no exception.  All threads executed successfully.  Hurrah !!  Infact jMeter give up by outOfMemory exception :)