Dollar Thrifty Automotive Group

Car Rental Agency Accelerates Success by Using Cutting-Edge Programming Model

Dollar Thrifty Automotive Group serves value-conscious travelers through its familiar brands, Dollar Rent A Car and Thrifty Car Rental. However, modifications to the company’s COBOL, mainframe-based, car rental system were time consuming. Dollar Thrifty remedied its problems by using Microsoft® .NET Framework 3.0 (formerly WinFX®) with Windows® Workflow Foundation and Windows Communication Foundation. To create the company’s next-generation car rental application, codenamed Rent Our Cars (ROC), developers are using Microsoft Visual Studio® Team Edition for Software Developers, and designing ROC to take advantage of Windows Server® 2003 today and the Windows Vista™ operating system in the future. With a consistent programming model, Dollar Thrifty improves developer productivity and connects emerging technologies and devices with existing systems.

Situation

Dollar Thrifty Automotive Group provides car rentals through two brands: Dollar Rent A Car and Thrifty Car Rental. Approximately 8,300 Dollar Thrifty employees serve travelers from company headquarters in Tulsa, Oklahoma. With an ever-expanding network of

Fast Facts
Number of developers	10
Estimated months to complete	16
Developer Tools	Microsoft Visual Studio 2005 Team Edition for Software Developers
Programming languages	Microsoft Visual C#
Programming model and technologies	Microsoft .NET Framework 3.0, Windows Communication Foundation, Windows Workflow Foundation

North American and international corporate-owned and franchised locations in 70 countries, the Dollar or Thrifty brands operate in virtually all of the top U.S. airport markets.
 
As Dollar Thrifty grew and expanded, and competition in the rental car business accelerated, company decision makers became aware of issues with the existing mainframe-based car rental system called “FastLane.” Issues included the following:

• Inflexible user interface. A serial rental agreement process didn’t let agents work the way they wanted to work. “Each agent approaches the customer’s needs in a slightly different way,” says Peter Osbourne, Director of ITTS Internet Research & Development at Dollar Thrifty. “The fact that agents had to work through screens in a prescribed manner tended to divert the agent’s attention away from the customer standing in front of them.”
• Lack of integration with modern devices and capabilities. “FastLane uses a rather odd ‘flavor’ of COBOL [Common Business-Oriented Language]. So, to integrate modern capabilities--like electronic signature capture and common devices like laser printers--was difficult,” says Jim Arrowood, Lead Architect for Dollar Thrifty.
• Poor performance during peak usage. Heavy usage or a glitch in a single database call might cause a system-wide slowdown and, consequently, longer lines and wait times at agent counters, affecting customer satisfaction, and, potentially, influencing a loss of repeat business.
• Costly workarounds. Although rare, a lost connection between the dumb terminal client and the mainframe required agents to work with printed manifests of reservations and fleet, write rental agreements using pen and paper forms, and calculate complex rates, taxes, and concession fees manually—while customers waited. When the connection was restored, agents had to manually enter data from paper contracts into the FastLane system.

Originally licensed or sold to people who operated car rental franchises, FastLane contained business rules unnecessary for Dollar Thrifty and, therefore, “dead code.” The FastLane code base was also inherently verbose. Programmers had a very difficult time deciphering where to insert or revise code among the many thousands of lines. Specifically, they found it hard to clearly identify the code that drove business logic.

“FastLane wasn’t fast,” remarks Osbourne. “A small change was a six-month undertaking, and it wasn’t uncommon for new features to take a year or two to develop and implement.”

Dollar Thrifty wanted a car rental system that would enhance customer experience and help the company be more agile in the face of competition, now and in the future. Specifically, Dollar Thrifty wanted to:

• Use a development system and programming model that would allow the company to connect with existing systems, use available development skills, and be more resilient to change over time.
• Be able to add new features quickly.
• Give agents maximum flexibility in their interactions with customers and the counter application.
• Give agents access to full system functionality even if a field office temporarily lost its connection to corporate headquarters.

Solution

Dollar Thrifty is developing the next generation of its car rental system, named Rent Our Cars (ROC), using the Microsoft® .NET Framework 3.0 (formerly WinFX®) so they can easily take advantage of Windows® XP and Microsoft Windows Server® 2003 today and use the Windows VistaTM (formerly codenamed “Longhorn”) operating system once it is available.

The .NET Framework 3.0 provides a managed code programming model for Windows, and it comes with new technologies for building applications that provide a visually compelling user experience, seamless communication across technology boundaries, and the ability to support a wide range of business processes.

Agents gain a better user interface that will enable them to think about and focus on the customer. Windows Workflow Foundation gave developers a vastly more flexible, cleaner way to do validation in the user interface … Jim Arrowood, Lead Architect, Dollar Thrifty Automotive Group

The .NET Framework 3.0 dramatically simplifies the development of many applications and expands the set of capabilities that developers have at their disposal when they’re building software.

A team of 10 programmers is relying on the .NET Framework 3.0 (formerly WinFX) with Windows Workflow Foundation and Windows Communication Foundation, and Microsoft Visual Studio® 2005 Team Edition for Software Developers to build ROC. ROC, which is a smart client application, will be deployed to the company’s 1,600 locations starting in the first quarter of 2007. Figure 1 shows ROC physical architecture.

Client computers run Windows XP Service Pack 2 (SP2). And because the .NET Framework 3.0 works with Windows XP SP2, Windows Server 2003, Windows Vista, and the Windows Server release code-named "Longhorn," Dollar Thrifty benefits from a consistent programming model across current and future operating systems.

Creating a Flexible User Interface

Developers at Dollar Thrifty took advantage of Windows Workflow Foundation to build validations in the smart client application. Windows Workflow Foundation provides the programming model, engine, and tools for quickly building workflow-enabled applications.

“With FastLane, the agent might not have found a missing field until the last screen, when the program validated all the inputs at once,” says Arrowood. “In ROC, the workflow engine in Windows Workflow Foundation validates data as the agent enters it, based on business rules. Windows Workflow Foundation helped us model business processes and develop an accurate validation set.”

Because they used Windows Workflow Foundation, developers didn’t have to write the workflow or validation logic from scratch. Plus, developers were able to create a flexible interface that lets agents work the way they want to work yet still satisfies all the business rules.

“By using Windows Workflow Foundation, we didn’t have to limit agents to one particular way of opening and completing a rental agreement,” Osbourne says.

Conducting Transactions Securely

Dollar Thrifty wanted to build ROC so that it could use Web services a transmit transactions securely over the Internet if necessary.
Developers initially worked with Microsoft ASP.NET Web services. By taking advantage of the declarative model in Windows Communication Foundation, developers easily converted these Web services to WS-* secure Web services. Windows Communication Foundation is the .NET Framework 3.0 technology for rapidly building connected systems, and is the first programming model built from the ground up for the development of service-oriented applications.

Crafting Offline Capabilities

To enable agents to work with or without a connection to the server, Dollar Thrifty encapsulated logic units of validation work as custom activities in Windows Workflow Foundation. Several of these activities can be used in workflows that can be executed on either the client or the server.

Figure 1. Rent Our Cars physical architecture

When a connection is lost, the car rental application seamlessly switches to standalone mode. Validation occurs locally, and rental agreements move into a queue. When the connection has been restored, the smart client synchronizes with and sends new rental agreements to the central server via a Web service. Although not scheduled to be included in Dollar Thrifty’s initial deployment, the company expects to implement this functionality in a subsequent release.

To create and publish managerial reports, Dollar Thrifty relies on Microsoft SQL Server™ 2005 Reporting Services. The development team used the Microsoft.Reporting.WinForms.ReportViewer control embedded in the smart client to display reports, even from a disconnected data set.

Benefits

By using Windows Workflow Foundation and Windows Communication Foundation, Dollar Thrifty developers have helped the company truly move into the fast lane with a solution that improves agility for programmers and rental agents alike. By using the .NET Framework 3.0, developers reduced the amount of code they write and experienced other productivity benefits.

“Agents gain a better user interface that will enable them to think about and focus on the customer,” says Arrowood. “Windows Workflow Foundation gave developers a vastly more flexible, cleaner way to do validation in the user interface, and the ability to re-use that validation elsewhere. The highly visual Workflow Designer hosted in Visual Studio 2005 Team System helped developers work with visual representations of code.”

Streamlined Development

Windows Workflow Foundation—especially the Workflow Designer—simplified development. Dollar Thrifty programmers used the

We expect to implement new features in only weeks. That’s the value of using the .NET Framework 3.0—we improve agility and keep our competitive edge. Peter Osbourne, Director of ITTS Internet Research & Development, Dollar Thrifty

Workflow Designer to create and modify workflows. When creating a workflow, they had at their disposal the Workflow Designer toolbox, which contains icons that can be dragged and dropped onto the design surface. And each activity has properties and events that the developers set in Visual Studio.

“Windows Workflow Foundation makes the development process easier and more intuitive,” remarks Arrowood. “It’s revolutionary because it provides an API [application programming interface] that anybody can use; you don’t have to go buy server solutions to run this. You can build it, and host it in your own applications. In a matter of minutes, you can have your own workflows built out.”

Because Dollar Thrifty programmers only need to understand one API to write both the Web services and the counter application, they can continue to be more productive.

“We expect to implement new features in only weeks,” says Osbourne. “That’s the value of using the .NET Framework 3.0—we improve agility and keep our competitive edge.”

“True Code Re-Use”

Dollar Thrifty has experienced unprecedented re-use of code and a great deal of flexibility in how programmers use the workflows they build.

“We can use a workflow from the ROC smart client and snap it into another process,” says Arrowood. “The application we plug it into doesn’t have to be on a smart client.”

Osbourne adds, “Object-oriented programming didn’t produce as much code re-use as people expected it would. Windows Workflow Foundation is revolutionary because workflows have been quite simple to create and to reuse. The result is fewer lines of code to write, manage, and debug.”

Programmers still using typical patterns like model view controller and model view presenter, but taking advantage of Windows Workflow Foundation gives them “a greater degree of control,” according to Arrowood.

Agile Development Team, Agile Business

The Dollar Thrifty development team is more agile and better able to support the business because the .NET Framework 3.0 and cutting-edge technologies, such as Windows Workflow Foundation, let developers focus more intently on what a person, task, or workflow needs to do, and worry less about how to code it.

“Developers can more readily think in business and process terms and focus less on how to chain steps of a workflow together with Boolean operators,” remarks Arrowood.

Windows Workflow Foundation also improves agility of the overall development team because it helps Dollar Thrifty development project managers use resources flexibly and assign people according to strengths, skills, and interests.

“One developer can work on one piece of a workflow and then integrate it into a composite workflow for a complete system. The Microsoft tools and technologies let developers use existing skills, play to their strengths, and help everyone contribute to the success of the project,” says Arrowood.

“Future-Proof” Systems

By using the .NET Framework 3.0 and Windows Communication Foundation, Dollar Thrifty can use existing and emerging technologies and devices to connect with company systems, use available development skills, modernize services, and stay on the competitive cutting-edge.

Dwayne Townsend, Feature Team Lead at Dollar Thrifty, says, “Windows Communication Foundation and Windows Workflow Foundation allow us the flexibility to help meet one of our toughest requirements: to create a product with a lifespan of 10+ years. Although we cannot predict what the future requirements may be, the added flexibility that the .NET Framework 3.0 gives us puts us in a better position to adapt to those unknown requirements in the future.”

The Dollar Thrifty development team also can write code once and send it over different communication protocols. For example, in ROC, the counter application used by rental agents connects to Web services via binary HTTP. In the past, the drawback would have been a loss of interoperability with the Java stack that Dollar Thrifty partners use to interact with the company. With Windows Communication Foundation, instead of building completely separate Web services with tightly coupled communication routines, developers can expose the different end point.

Arrowood says, “We can have a binary HTTP end point for the counter application and a standard XML Web service for the handheld applications. Behind the scenes, it’s the same code and business logic. It’s just a matter of making changes in a configuration file. We benefit from interoperability with partners and devices so that if we want to speak a particular version of XML or a particular version of SOAP, we can—without being limited by a single end point and without copying code. Windows Communication Foundation lets us change the configuration file without recompiling the application,” says Arrowood.

Because of its success with Windows Communication Foundation, Dollar Thrifty is considering using it to incorporate third-party content such as flight status. “The .NET Framework 3.0, Windows Workflow Foundation, and Windows Communication Foundation put us on the fast track to consume other services to enhance customer satisfaction,” concludes Osbourne.

Microsoft Visual Studio 2005
Microsoft Visual Studio 2005 is the world’s most popular development environment for designing, developing, and testing next-generation Windows®-based solutions and Web applications and services. By improving the development experience for Windows, the Web, mobile devices, and Microsoft Office, Visual Studio 2005 helps organizations deliver a variety of solutions more productively than ever before. Visual Studio Team System expands the product line with new software tools that enable greater communication and collaboration throughout the development life cycle. With Visual Studio 2005, businesses can deliver modern service-oriented solutions more efficiently.

For more information about Visual Studio 2005, go to:
msdn.microsoft.com/vstudio

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