Click here to close now.

Welcome!

AJAX & REA Authors: Liz McMillan, XebiaLabs Blog, AppDynamics Blog, Pat Romanski, Elizabeth White

Related Topics: AJAX & REA, Java

AJAX & REA: Article

Struts Validations Framework Using AJAX

Real-time data validation is one of the advantages of AJAX technology

Real-time data validation is one of the advantages of AJAX technology. By applying this technology, the struts validation framework will enrich the struts MVC and move the Web application closer to the desktop application.

The validation framework is used to validate fields. There are many ways to do validation on a Web application. It falls into two categories: server-side and client-side. A struts validation framework is one of the best frameworks for a Java-based Web application environment. It can configure the application using server-side validation and employ the error message that renders on the validation process invoked during the request processing time, or it can do client-side validation by using the JavaScript rendered on the requested page.

AJAX is a JavaScript technology that can asynchronously call the server and fetch the XML documents that are so popular lately. One of its uses is real-time data validation.

This article is concerned with enriching the existing struts validation framework with AJAX. A few components, such as a controller, have to be developed to select the validation framework and render the specific format message for the client side and a taglib to handle the error message rendering.

Prerequisites
You'll need a Windows system with Eclipse and the Tomcat application server. Make sure that the MSXML 3.0 ActiveX object is registered on your operating system. You'll also need the Struts library (http://struts.apache.org) and the JDOM library (www.jdom.org) for XML development (see Figure 1 and Figure 2).

Server-Side Scenario
StrustsActionServlet
We have to extend the class from org.apache.struts.action.ActionServlet to get the servletMapping variable that stores the information on how the extension will be formatted for action classes into the action path as a browser address. When the code is added, we have to configure web.xml as a Web application descriptor for the application server.

The web.xml configuration:

...
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>net.sf.struts.servlet.StrutsActionServlet</servlet-class>
...
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
...

The StrutsActionServlet Java code looks like this:

public class StrutsActionServlet extends the ActionServlet.
{
public String getServletMapping() {
return this.servletMapping;
}
}

AjaxValidationRequestProcessor
To support the existing Struts framework in the first step, we have to extend the RequestProcessor from the Struts package. We have to customize the request processor because we have to distinguish how we're going to do the validation - by using the existing Struts framework or the AJAX concept - and because we'll be making a contract between the server and client on how to interpret the message. In the message rendering we'll use the XML format, which is a good media messaging format. The definition of the XML format we'll apply is:

XML Format
<?xml version="1.0" encoding="UTF-8"?>
<message>
<identity name=messageAreaId>
     <description>
   MessageValue
</description>
</identity>
</message>

Description

  • Identity is the ID for the client JavaScript to acknowledge where the message will be placed.
  • Description is the result after the error message rendering from the server side.
First we need to get the servlet mapping configuration from the Web descriptor before moving onto the process mapping. After invoking the process, the application will prepare the instance of the form that inherits from the AjaxForm class. The processing manages AJAX validation and should check to ensure that the request from the client isn't using the struts validation framework. Other processes to perform during the request are process populate for collecting the information sent by the client into the action form, and process validation by using the method from the existing Struts validation framework that already exists in the parent class of AjaxValidationRequestProcessor (TilesRequestProcessor).

The validation process from the TilesRequestProcessor will invoke all the validation based on the struts validation framework and store the action errors into the request. What we need is to parse the action errors into pieces and generate the XML message validation that will be sent to the client side. Since we want to change the behavior of how the validation will be backed, the validation process should check the indicator of the validation framework being used (see Figure 3).

Generate the XML messages using JDOM as the processing engine. As shown in Figure 4, when the process validation is invoked and the condition of the validation framework is equal with the AJAX validation framework, the process will continue to populate the error message and build the XML message validation.

ErrorMessageHandler
This class handles the functionality of the XML message builder. This Java class will be building the XML message based on the identity and description property. After the caller invokes the buildXMLMessage, it will prepare the document and set the root element of the XML message. This class also has an addNextXMLMessage function to add more validation messages into the XML (see Listing 1).

The process method will set the content type of the response as "text/xml" and send the XML message as a string. The function of the process on the AjaxValidationRequestProcessor code will look like Listing 2.

The processValidation method will populate the action errors and construct the message based on the format contract of the XML for the client. The function of processValidation on AjaxValidationRequestProcessor code will be look like:

...
ActionErrors errors = (ActionErrors) request.getAttribute(Globals.ERROR_KEY);
Locale locale = (Locale) request.getAttribute(Globals.LOCALE_KEY);
generateXMLMessage(errors, identity, locale, sbXMLMessage);
...

Client-Side Scenario
Build the Taglib Component

  • AjaxJavaScriptLibraryTag: The taglib component to render the JavaScript function at the client side for basic XMLHTTP controller functions.
  • AjaxErrorHtmlRenderTag: The taglib component to render the area of the error message at the JSP page.
Configuring the Taglib Definition
After developing the taglib component, we need to configure the taglib tld file as shown in Listing 3.

Build JSP and Struts Configuration
To simulate the result of the validation processing, we first need to build the presentation layer by incorporating the taglib that we've build. In this case I'm trying to give an example validation by using the validation rules component from Struts, and also the validation that comes from the form itself. Prepare five textboxs under the JSP page. The first to fourth textbox are using the validation rule configuration, and the fifth textbox is using the validate process from the action form. Other than that, we also need a submit button to simulate that after submitting the form, the existing struts validation are still working without AJAX. The user interface will look like Figure 5.

More Stories By Sonny Hastomo

Sonny Hastomo is an IT architect at Sun Microsystems, Indonesia, for the telecommunication industry division. His currently is focusing on providing solution design, sizing, implementation, consulting services, and quality support to customers in their evaluation of their IT challenges.

Comments (9)

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.


@CloudExpo Stories
There is little doubt that Big Data solutions will have an increasing role in the Enterprise IT mainstream over time. 8th International Big Data Expo, co-located with 17th International Cloud Expo - to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA - has announced its Call for Papers is open. As advanced data storage, access and analytics technologies aimed at handling high-volume and/or fast moving data all move center stage, aided by the cloud computing bo...
Every day we read jaw-dropping stats on the explosion of data. We allocate significant resources to harness and better understand it. We build businesses around it. But we’ve only just begun. For big payoffs in Big Data, CIOs are turning to cognitive computing. Cognitive computing’s ability to securely extract insights, understand natural language, and get smarter each time it’s used is the next, logical step for Big Data.
There's no doubt that the Internet of Things is driving the next wave of innovation. Google has spent billions over the past few months vacuuming up companies that specialize in smart appliances and machine learning. Already, Philips light bulbs, Audi automobiles, and Samsung washers and dryers can communicate with and be controlled from mobile devices. To take advantage of the opportunities the Internet of Things brings to your business, you'll want to start preparing now.
Enterprises are fast realizing the importance of integrating SaaS/Cloud applications, API and on-premises data and processes, to unleash hidden value. This webinar explores how managers can use a Microservice-centric approach to aggressively tackle the unexpected new integration challenges posed by proliferation of cloud, mobile, social and big data projects. Industry analyst and SOA expert Jason Bloomberg will strip away the hype from microservices, and clearly identify their advantages and d...
In a world of ever-accelerating business cycles and fast-changing client expectations, the cloud increasingly serves as a growth engine and a path to new business models. Dynamic clouds enable businesses to continuously reinvent themselves, adapting their business processes, their service and software delivery and their operations to achieve speed-to-market and quick response to customer feedback. As the cloud evolves, the industry has multiple competing cloud technologies, offering on-premises ...
The 5th International DevOps Summit, co-located with 17th International Cloud Expo – being held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the...
Over the years, a variety of methodologies have emerged in order to overcome the challenges related to project constraints. The successful use of each methodology seems highly context-dependent. However, communication seems to be the common denominator of the many challenges that project management methodologies intend to resolve. In this respect, Information and Communication Technologies (ICTs) can be viewed as powerful tools for managing projects. Few research papers have focused on the way...
As the world moves from DevOps to NoOps, application deployment to the cloud ought to become a lot simpler. However, applications have been architected with a much tighter coupling than it needs to be which makes deployment in different environments and migration between them harder. The microservices architecture, which is the basis of many new age distributed systems such as OpenStack, Netflix and so on is at the heart of CloudFoundry – a complete developer-oriented Platform as a Service (PaaS...
The OpenStack cloud operating system includes Trove, a database abstraction layer. Rather than applications connecting directly to a specific type of database, they connect to Trove, which in turn connects to one or more specific databases. One target database is Postgres Plus Cloud Database, which includes its own RESTful API. Trove was originally developed around MySQL, whose interfaces are significantly less complicated than those of the Postgres cloud database. In his session at 16th Cloud...
SAP is delivering break-through innovation combined with fantastic user experience powered by the market-leading in-memory technology, SAP HANA. In his General Session at 15th Cloud Expo, Thorsten Leiduck, VP ISVs & Digital Commerce, SAP, discussed how SAP and partners provide cloud and hybrid cloud solutions as well as real-time Big Data offerings that help companies of all sizes and industries run better. SAP launched an application challenge to award the most innovative SAP HANA and SAP HANA...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading in...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect...
The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential. The DevOps Summit at Cloud Expo – to be held June 3-5, 2015, at the Javits Center in New York City – will expand the DevOps community, enable a wide...
There is no question that the cloud is where businesses want to host data. Until recently hypervisor virtualization was the most widely used method in cloud computing. Recently virtual containers have been gaining in popularity, and for good reason. In the debate between virtual machines and containers, the latter have been seen as the new kid on the block – and like other emerging technology have had some initial shortcomings. However, the container space has evolved drastically since coming on...
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 bu...
Cloud Expo, Inc. has announced today that Andi Mann returns to DevOps Summit 2015 as Conference Chair. The 4th International DevOps Summit will take place on June 9-11, 2015, at the Javits Center in New York City. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited to help the great team at ...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Ar...
All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo, June 9-11, 2015, at the Javits Center in New York City. Learn what is going on, contribute to the discussions, and ensure that your enter...
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, a...
In a recent research, analyst firm IDC found that the average cost of a critical application failure is $500,000 to $1 million per hour and the average total cost of unplanned application downtime is $1.25 billion to $2.5 billion per year for Fortune 1000 companies. In addition to the findings on the cost of the downtime, the research also highlighted best practices for development, testing, application support, infrastructure, and operations teams.