Click here to close now.

Welcome!

Java Authors: Liz McMillan, Jason Bloomberg, Esmeralda Swartz, Trevor Parsons, Jnan Dash

Related Topics: Java, Wireless

Java: Article

Java J2EE Lite with Spring Framework

The combined burden of EJBs and coarse-grained component design has given the term test driven design a new meaning

J2EE applications of late have become weight conscious. The combined burden of EJBs and coarse-grained component design has given the term test driven design a new meaning: technology driven design! Fortunately a host of lightweight solutions are emerging, such as PicoContainer, Spring Framework, Hivemind, Hibernate, Castor, and Webwork. In this article I'll discuss my experience with the Spring Framework and how it can be used to make a J2EE application more maintainable, testable, and better performing.

Although there are many areas that Spring 1.2.4 covers, I will be covering only Spring IoC (Inversion of Control) and Spring AOP (Aspect-Oriented Programming). These two along with the (non-Spring) concept of coding to interfaces form the cornerstone on which other Spring technologies are based.

Using Spring AOP and IoC we will see how you can replace container-provided infrastructure services for the following services, a la carte:

  • Logging
  • Transactions
  • Profiling
  • Auditing
  • Exception monitoring
We will also see:
  • Switching XA data sources for nonXA ones for certain methods
  • Accessing stateless session beans (SLSB) via a Spring application context
  • Accessing Spring application Contexts from a webapp
  • Integration tests using IoC and JUnit
  • Unit testing using EasyMock and JUnit
To demonstrate these services we will be using a simple ordering application, made2order.

made2order Application
The made2order application showcases the above infrastructure services using the Spring Framework. Figure 1 shows the architecture of the application components.

The application consists of an OrderService interface implemented by the OrderServiceImpl concrete class. The OrderDAO interface is implemented by the JdbcOrderDAO concrete class. Finally the domain objects are represented by the Order and the LineItem classes. These six classes represent the POJO-based core business application (in magenta); the other classes are Spring classes (used for infrastructure functionality). JSP are used for presentation, packaged in the Web app, and there are two classes for testing

Database Design and Business Interface
made2order has a very simple database design shown in Figure 2.

The business interface for the made2order application is shown in Listing 1. The OrderServiceImpl class implements the above business methods. Note that the getDao() and setDao(...) methods are needed for "injecting" a dependent DAO (Data Access Object Pattern) into the service (we will see more about this later) http://java.sun.com/blueprints/corej2eepatterns/ Patterns/DataAccessObject.html.

The implementation of these methods deals only with the business logic (and DAO interaction). It does not have knowledge of infrastructure services such as:

  • Transactions
  • Logging of enter/exiting from methods
  • Auditing
  • Profiling long-running methods
  • Reporting when exceptions occur
  • Data source switching
We will see how the above services will be applied to the made2order application in a non-invasive manner.

Using made2order
The accompanying application is meant to serve as an example for the Spring technologies discussed in this article. The downloadable bundle at Listing 1 is a zip file that can be imported into the Eclipse IDE as an Eclipse project.

You can do either one of the following actions (or both) as you read through this article:

  • Go through the source code using your favorite IDE and run JUnit tests to understand the examples. The JUnit test suite file (com.order.acme.OrderServiceIntegrationTest.java) in the test folder contains several methods to test the above services.
  • Install the Web app in a J2EE application server (does not need EJB support) and navigate through the Web pages with the examples.
We will start with the Spring BeanFactory.

Spring Bean Factory and IoC
The Spring BeanFactory represents a class that manages the life cycle of singleton services (among other things). These services are injected with dependencies using Inversion of Control (www.martinfowler.com/articles/injection.html). Services that depend on external resources are "told" what those dependencies are instead of "getting" them using the Service Locator pattern (http://java.sun.com/blueprints/corej2eepatterns/ Patterns/ServiceLocator.html).

The injection of dependents is achieved either via a constructor or setter injection. The JavaBean that represents the service has a "set" method that accepts the dependant (setter injection) or it has a constructor that accepts the dependent object (constructor injection). Using an XML configuration file, the service object is configured with its dependent objects using either of these two mechanisms. (The XML file is just one of many formats the configuration can be specified in, others being properties files or just plain Java code.)

There can be one or more bean factories in an application. Bean factories can be overlaid, such that there is one for production but it's overlaid by the one for development.

The bean factory is accessed by the presentation layer to access services offered by the application. In made2order, the OrderService service is needed as a singleton. The OrderService implementation is dependent on an implementation of OrderDAO. The OrderDAO implementation in turn is dependent on JdbcTemplate object, (a Spring-supplied helper class that helps with JDBC operations). The JdbcTemplate requires an implementation of a data source. In this case, myDataSource is a data source implementation that is specified in the BeanFactory and injected into the JdbcTemplate.

The BeanFactory returns a singleton of OrderService after "injecting" required dependencies in it as shown in the Figure 3.

Note that an implementation is injected into an interface at each level.

Figure 3 is represented in the XML file orderContext.xml shown in Listing 2. In this listing we see that the BeanFactory defines two data sources. During configuration, either of the data sources is injected into the JdbcTemplate instance.

Spring Proxies
In the general sense of the word, a proxy is a class that sits between the business class and the client. In the context of Spring, however, a proxy is either a JSE dynamic proxy or a static proxy that implements infrastructure services and is "injected" with a dependency that is the target business class. Then, instead of the client being given a reference to the target service, it's given a reference to the proxy. In this manner the behavior implemented in the proxy is interjected into the service seen in Figure 4.

With the current release, Spring proxies allow interception at the method level only, whereas some full-blown AOP environments allow field-level interception also. Proxies can be dynamic (JSE dynamic proxies), in which case Java interfaces are proxied; or they can be static, in which case bytecode modification occurs. Understandably, static proxies outperform dynamic ones but only marginally.

Interception is implemented using concepts from AOP: pointcuts and advice.

Pointcuts and Advice
Advice classes specify the actual work to do upon interception whereas pointcuts tell Spring where to apply advice.

The combination of a pointcut and an advice is bundled in what Spring calls an Advisor (see Figure 5).

We will see Advice, Advisors, and Pointcut classes in action in a made2order application when we apply infrastructure services to the business classes.

The following sections explain how each infrastructure service has been implemented.

Transaction Service
The OrderService's placeOrder(...), modifyOrder(...), and dropOrder() methods need to be transaction-bound. For this we modify the orderContext.xml file by configuring a Spring-supplied transactional proxy called TransactionProxyFactoryBean. As shown in the Listing 3, an instance of this proxy is called myProxiedServiceWithSeveralInterceptors.

The TransactionAttributes section is supplied with regular expressions that represent the methods that need to be transaction bound (PROPAGATION_REQUIRED) and those that are not (PROPAGATION_SUPPORTS).

Also, the target of this proxy is specified as orderService, which is the instance of the OrderServiceImpl.

Note that a transactionManager is injected into the proxy. An instance of transactionManager is set up elsewhere in the configuration file.

The preInterceptors are a list of Advices and/or Advisors that are also tacked onto this proxy in what is called a chain of interceptors. We will see each of these in turn later. For now, note that preInterceptors are invoked before the target is invoked in the order specified.

Seeing Transactions in Action Using JUnit
For testing transactions there are two test methods in the test suite: testNonProxiedServiceForModifyingAnOrder() and testProxiedServiceForModifyingAnOrder(). Both these methods call the modifyOrder(...) method on the non-proxied service in one case and proxied service in the other. The modifyOrder(...) method updates the ORDER_TABLE table first and then each lineItem in the ITEM_TABLE. The test method updates an order with two line items. The second lineItem has a description whose length is greater than the column width in the database. This forces an error upon update of the line item description in the database. Both the test methods update the ORDER_TABLE first and then the first lineItem in the LINE_ITEM table before throwing an exception while trying to update the long description in the second line item. The proxied method issues a rollback whereas the non-proxied method commits the update to the ORDER_TABLE and the first lineItem in the ITEM_TABLE.

More Stories By Pankaj Tandon

Pankaj Tandon is a software engineer at Crowncastle. His interests include object-oriented design and development and architecting the software process using open source technologies. He is a Sun Certified Java developer for the Java 2 platform. He lives in Pittsburgh, PA, plays guitar, and mixes music in his spare time.

Comments (6) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Pankaj Tandon 02/21/06 10:38:18 AM EST

I just realized that if you are here then you have already found the online version of the article.. here is the link to the downloadable artifact then..
http://res.sys-con.com/story/feb06/180377/source.html

Click on "Additional Code II" to get the full webapp+ code.

Pankaj Tandon 02/17/06 05:48:23 PM EST

Hi all,
I have received several emails from folks telling me about this snafu on JDJs part.
The link is there burried somewhere in the JDJ labyrinth.
You can get to it and some performance analysis at:
http://technochord.blogspot.com/2006/02/j2ee-lite-with-spring-framework....

Bob Raker 02/16/06 11:37:12 AM EST

This was a very good article. But, where the hell does one go to download listing 9-20. Thanks.

Rob Moore 02/14/06 12:14:11 PM EST

Is the sample code available?

Thanks,

Rob

SYS-CON Brazil News Desk 02/14/06 09:46:50 AM EST

J2EE applications of late have become weight conscious. The combined burden of EJBs and coarse-grained component design has given the term test driven design a new meaning: technology driven design! Fortunately a host of lightweight solutions are emerging, such as PicoContainer, Spring Framework, Hivemind, Hibernate, Castor, and Webwork. In this article I'll discuss my experience with the Spring Framework and how it can be used to make a J2EE application more maintainable, testable, and better performing.

SYS-CON India News Desk 02/13/06 02:55:13 PM EST

J2EE applications of late have become weight conscious. The combined burden of EJBs and coarse-grained component design has given the term test driven design a new meaning: technology driven design! Fortunately a host of lightweight solutions are emerging, such as PicoContainer, Spring Framework, Hivemind, Hibernate, Castor, and Webwork. In this article I'll discuss my experience with the Spring Framework and how it can be used to make a J2EE application more maintainable, testable, and better performing.

@ThingsExpo Stories
Health care systems across the globe are under enormous strain, as facilities reach capacity and costs continue to rise. M2M and the Internet of Things have the potential to transform the industry through connected health solutions that can make care more efficient while reducing costs. In fact, Vodafone's annual M2M Barometer Report forecasts M2M applications rising to 57 percent in health care and life sciences by 2016. Lively is one of Vodafone's health care partners, whose solutions enable older adults to live independent lives while staying connected to loved ones. M2M will continue to gr...
Dave will share his insights on how Internet of Things for Enterprises are transforming and making more productive and efficient operations and maintenance (O&M) procedures in the cleantech industry and beyond. Speaker Bio: Dave Landa is chief operating officer of Cybozu Corp (kintone US). Based in the San Francisco Bay Area, Dave has been on the forefront of the Cloud revolution driving strategic business development on the executive teams of multiple leading Software as a Services (SaaS) application providers dating back to 2004. Cybozu's kintone.com is a leading global BYOA (Build Your O...
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
What exactly is a cognitive application? In her session at 16th Cloud Expo, Ashley Hathaway, Product Manager at IBM Watson, will look at the services being offered by the IBM Watson Developer Cloud and what that means for developers and Big Data. She'll explore how IBM Watson and its partnerships will continue to grow and help define what it means to be a cognitive service, as well as take a look at the offerings on Bluemix. She will also check out how Watson and the Alchemy API team up to offer disruptive APIs to developers.
The IoT Bootcamp is coming to Cloud Expo | @ThingsExpo on June 9-10 at the Javits Center in New York. Instructor. Registration is now available at http://iotbootcamp.sys-con.com/ Instructor Janakiram MSV previously taught the famously successful Multi-Cloud Bootcamp at Cloud Expo | @ThingsExpo in November in Santa Clara. Now he is expanding the focus to Janakiram is the founder and CTO of Get Cloud Ready Consulting, a niche Cloud Migration and Cloud Operations firm that recently got acquired by Aditi Technologies. He is a Microsoft Regional Director for Hyderabad, India, and one of the f...
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal today!
SYS-CON Events announced today that SoftLayer, an IBM company, has been named “Gold Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015 at the Javits Center in New York City, NY, and the 17th International Cloud Expo®, which will take place November 3–5, 2015 at the Santa Clara Convention Center in Santa Clara, CA. SoftLayer operates a global cloud infrastructure platform built for Internet scale. With a global footprint of data centers and network points of presence, SoftLayer provides infrastructure as a service to leading-edge customers ranging from ...
SYS-CON Events announced today that Cisco, the worldwide leader in IT that transforms how people connect, communicate and collaborate, has been named “Gold Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Cisco makes amazing things happen by connecting the unconnected. Cisco has shaped the future of the Internet by becoming the worldwide leader in transforming how people connect, communicate and collaborate. Cisco and our partners are building the platform for the Internet of Everything by connecting the...
SYS-CON Events announced today that Liaison Technologies, a leading provider of data management and integration cloud services and solutions, has been named "Silver Sponsor" of SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York, NY. Liaison Technologies is a recognized market leader in providing cloud-enabled data integration and data management solutions to break down complex information barriers, enabling enterprises to make smarter decisions, faster.
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.
SYS-CON Events announced today that Ciqada will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Ciqada™ makes it easy to connect your products to the Internet. By integrating key components - hardware, servers, dashboards, and mobile apps - into an easy-to-use, configurable system, your products can quickly and securely join the internet of things. With remote monitoring, control, and alert messaging capability, you will meet your customers' needs of tomorrow - today! Ciqada. Let your products take flight. For more inform...
SYS-CON Events announced today that ProfitBricks, the provider of painless cloud infrastructure, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY., and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. ProfitBricks is the IaaS provider that offers a painless cloud experience for all IT users, with no learning curve. ProfitBricks boasts flexible cloud servers and networking, an integrated Data Center Designer tool f...
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet conditions, Dyn ensures traffic gets delivered faster, safer, and more reliably than ever.
SYS-CON Events announced today that Open Data Centers (ODC), a carrier-neutral colocation provider, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Open Data Centers is a carrier-neutral data center operator in New Jersey and New York City offering alternative connectivity options for carriers, service providers and enterprise customers.
SYS-CON Events announced today that On the Avenue Marketing Group, a sales and marketing firm that utilizes events to market and sell products to consumers, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. On the Avenue Marketing Group (OTA) is a sales and marketing firm that utilizes events to market and sell products to consumers. On behalf of our clients, we attend thousands of fairs, festivals, expos, concerts, conferences, and sporting events annually, helping them reach millions of individuals ...
SYS-CON Events announced today that BroadSoft, the leading global provider of Unified Communications and Collaboration (UCC) services to operators worldwide, has been named “Gold Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. BroadSoft is the leading provider of software and services that enable mobile, fixed-line and cable service providers to offer Unified Communications over their Internet Protocol networks. The Company’s core communications platform enables the delivery of a range of enterprise and consumer calling...
SYS-CON Events announced today that ActiveState, the leading independent Cloud Foundry and Docker-based PaaS provider, has been named “Silver Sponsor” of SYS-CON's DevOps Summit New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. ActiveState believes that enterprises gain a competitive advantage when they are able to quickly create, deploy and efficiently manage software solutions that immediately create business value, but they face many challenges that prevent them from doing so. The Company is uniquely positioned to help address these challenges thro...
SYS-CON Events announced today that Vitria Technology, Inc. will exhibit at SYS-CON’s @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Vitria will showcase the company’s new IoT Analytics Platform through live demonstrations at booth #330. Vitria’s IoT Analytics Platform, fully integrated and powered by an operational intelligence engine, enables customers to rapidly build and operationalize advanced analytics to deliver timely business outcomes for use cases across the industrial, enterprise, and consumer segments.
SYS-CON Events announced today that Alert Logic, the leading provider of Security-as-a-Service solutions for the cloud, has been named “Bronze Sponsor” of SYS-CON's 16th International Cloud Expo® and DevOps Summit 2015 New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY, and the 17th International Cloud Expo® and DevOps Summit 2015 Silicon Valley, which will take place November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA.