Weblogic Authors: Yeshim Deniz, Elizabeth White, Michael Meiner, Michael Bushong, Avi Rosenthal

Related Topics: Weblogic

Weblogic: Article

Building Adaptive Applications With Reusable Components

Building Adaptive Applications With Reusable Components

Building Adaptive Applications With Reusable Components

Two daunting tasks face application architects and project managers alike.The first is to architect a solution that will reduce the risks involved with implementing new and changing business requirements during the application development and post-application deployment stages of a project. The second is to architect a solution that will reduce the development time and increase the corporation's Return on Investment (ROI) in past projects by reusing prebuilt visual and business components

BEA WebLogic Portal 4.0 contains frameworks designed to allow the creation of adaptive applications using visual, data-cleansing, and business components reaped from previous application development projects. The Webflow and Pipeline frameworks enable developers to dynamically link together reusable components that follow the Model-View-Controller (MVC) design pattern.

Webflow Framework
The Webflow framework is designed to build Web applications that can adapt to changing Web-business requirements. The main controller behind the Webflow framework is the WebflowExecutor class (see Figure 1). The WebflowExecutor intercepts events emanating from a visual, input processor or business component, consults with a centralized XML-based application scenario file; and invokes the next predefined visual, input processor or business component.

The XML-based application scenario file enables the decoupling of application components, which is key to developing adaptive applications with reusable components. During runtime, each component sends an event type and location identifier to the WebflowExecutor via the WebflowServlet. The WebflowExecutor then determines the next component in the sequence to execute. The runtime determination of sequence flows by the WebflowExecutor allows the developer to simply modify the scenario file in order to alter the business flow of the online application. The alteration of the sequence file may include rearranging existing links between components, removing existing components, or adding new components. The ability to add and remove components in an application that uses the Webflow and Pipeline frameworks without any code modifications is made possible by using the provided JSP Webflow tag libraries (in the case of visual components) and by implementing the appropriate interfaces (in the case of input processors and pipeline components).

Visual Components
The visual components that can be used in the Webflow framework are JSP and HTML pages. The only supported events that visual components can generate are hyperlinks and forms. In the case of JSP pages, the developer need only inform the Webflow servlet of the event type and origination ID, which would then be forwarded to the WebflowExecutor. JSP helper tag libraries are provided to help the developer in developing JSP pages, as shown below.

<a href="<webflow:createWebflowURL origin="checkout.jsp" event="link.continue" httpsInd="http"/>"> Check Out </a>

The example above is invoked when the user selects that corresponding hyperlink, in which case the origin ID ("checkout.jsp"), the event type ("link.continue"), and the protocol to be used ("http") are sent to the Webflow servlet. In the case of HTML visual components, the visual component developer would pass the Webflow servlet the same information as a JSP visual component. However, since JSP tag libraries are not usable in HTML pages, the information has to be explicitly placed in the appropriate format, as shown below:

<a href=http://localhost:7501/example/
=order&origin=checkout.jsp&event=link.continue> Check Out</a>
The fact that destinations aren't hard-coded in each visual component allows the developer to rearrange the site map without having to modify JSP or HTML code.

Input Processor Components
In order to ensure that the information being sent to the business components is valid and well-formatted, a data-cleansing step should be added to the execution flow. InputProcessors are specialized Java classes that can be used to perform the data-cleansing task. To add an InputProcessor to the Web application scenario, a developer would simply implement the InputProcessor interface or extend the InputProcessorSupport class (see Figure 2), and link the InputProcessor to the appropriate components in the XML-based scenario file.

The InputProcessor developer may also use an implementation of the ValidatedValues interface to report back to the visual component the results of the completed data-cleansing task. The visual component developer can then access the status of each form field via the JSP tag. In addition to cleansing data, InputProcessors can also be used to perform conditional branching within a Web application where, depending upon the branching logic contained in the InputProcessor, the return value will tell the WebflowExecutor which visual or business component to execute next.

After the InputProcessor completes its processing, a return object is sent back to the WebflowExecutor. The return object, coupled with the knowledge of the InputProcessor type, allows the WebflowExecutor to determine the next component to execute by referring to the XML-based scenario file. Similar to the visual components, hard-coded links to other components are not implemented in the InputProcessors, which allow the developer to reuse data-cleansing and conditional-branching components, and provides the ability to change the application's behavior without recoding.

Pipeline Framework
The Pipeline framework is designed to build business applications that can adapt to changing business requirements. The framework follows the Pipe-and-Filter architectural pattern and works in conjunction with the Webflow framework. After the WebflowExecutor has consulted the XML-based application scenario file and determined that a pipeline needs to be executed, control is handed over to the PipelineExecutor to execute the pipeline. After completion of the pipeline invocation, control is handed back to the WebflowExecutor to determine which components in the application sequence to invoke next. It's important to understand that all the components in the Webflow and Pipeline frameworks can be linked together in any sequence and that information may be shared between these components through the PipelineSession object.

The PipelineExecutor serves as the controlling class in the Pipeline framework, handling the linkage and exceptions between pipeline components. The pipeline components in the Pipeline framework are essentially business components that perform the required business functionality. Each pipeline can be composed of a sequence of one or more pipeline components and exceptions can be generated by any of the pipeline components. These exceptions can either be fatal, which stops the processing of the pipeline, or nonfatal, which allows the next component in the sequence to be invoked. A pipeline can also be wrapped in a single transactional context, allowing the components in the pipeline to act as one atomic unit of work. As with the WebflowExecutor in the Webflow framework, the PipelineExecutor references a pipeline scenario script to determine which pipeline component to invoke next, given a specific event and origination.

Business Component
The business components that can be linked together in a single pipeline may consist of Java and Stateless Session EJB classes. The business component (i.e, pipeline component) is generally used to execute coarse-grain business logic or integrate to existing back-end systems.

To add a business component to the pipeline sequence, a developer would simply implement the PipelineComponent interface or extend the PipelineComponentSupport class (see Figure 3), and link the business component implementation to the other business components in the XML-based pipeline scenario file.

In order to allow the sharing of information in a pipeline, the PipelineSession object is passed between business components via the required Process method implementation. The PipelineSession object can also be contained within the same transactional context as the components in the pipeline itself.

GUI Editor Tool
Since the XML-based scenario files are integral to the Webflow and Pipeline frameworks, the ability to create and edit these files is incorporated into the WebLogic Portal GUI tool, the E-Business Control Center (EBCC). Each framework has its own specialized drawing area (see Figures 4 and 5) and multiple scenario files are differentiated via a namespacing scheme. The visual editing tool is very easy to use with drag-and-drop, zoom, scenario-linking, and attribute-editing features. The ability to graphically create an application by linking together visual and business components from a corporation's certified IT application component library is a powerful step in building adaptable applications in a substantially reduced time frame.

The Webflow and Pipeline frameworks, which are part of the BEA WebLogic Portal product, address the need for an architecture that is able to adapt to changing business requirements and improve ROI by enabling the reuse of application components.

By simply implementing the required framework interfaces, visual, data-cleansing, and business components can easily be linked together to form a fully functional application. This application can then be adapted to address new business functionality by visually relinking new or existing components from previous projects. Additionally, the implementation of the MVC design pattern provides the separation between the presentation logic and the underlying business processes, thus allowing the ability to modify any one of the tiers without impacting the others.

More Stories By Dwight Mamanteo

Dwight Mamanteo is a technical manager with the Global Alliances Technical Services
organization at BEA Systems. He has been with BEA since 1999 and his current
job responsibilities include providing technical enablement support to BEA's
strategic SI and ISV partners. He has
been involved with object-oriented programming, design and architecture since 1993.

Comments (0)

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.

@ThingsExpo Stories
DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of the 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organizers to pass great deals to gre...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, led attendees through the exciting evolution of the cloud. He looked at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering m...
"Evatronix provides design services to companies that need to integrate the IoT technology in their products but they don't necessarily have the expertise, knowledge and design team to do so," explained Adam Morawiec, VP of Business Development at Evatronix, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
22nd International Cloud Expo, taking place June 5-7, 2018, at the Javits Center in New York City, NY, and co-located with the 1st DXWorld Expo will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
"MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.