Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion, Java IoT, Adobe Flex

ColdFusion: Article

A Complete Application with RPC Communications...

... between Flex and Java

This is a book excerpt from the book RIch Internet applications with Adobe Flex and Java.

Configuring the Server-Side Destination and Proxy

For security reasons (similar to the Java sandbox concept), Flash clients can only access the domains they come from, unless other servers declare, explicitly or implicitly, trust to SWF files downloaded from our domain by a corresponding record in a crossdomain.xml file. But our portfolio SWF wasn't loaded from finance.yahoo.com, and we aren't allowed to install crossdomain.xml on the Yahoo! servers. We'll use another technique called Flex proxy. When the user clicks on the News link in the data grid, the portfolio client will connect to our FDS Web application deployed under Tomcat (JRun, WebLogic), which will proxy our communication with Yahoo!. To configure the Flex proxy service, use the following section of the proxy-config.xml located in the \WEB-INF\flex directory:

   <destination id="YahooFinancialNews">
     <properties>
       <url>http://finance.yahoo.com/rss/headline</url>
     </properties>
   </destination>

Now Flex will contact http://finance.yahoo.com, get the news for the symbol specified, and return it back to the Flash client.

Processing the News Feed
The HTTPService converts the received data according to the value of the resultFormat property: e4x, flashvars, object (this is default), text, or xml.

If we knew that the results were coming back as name/value pairs concatenated with an ampersand, we could have picked the flashvars format. The text format is suitable for any raw text, but it's not easy to parse. The XML format is maintained for compatibility with pre-E4X versions of the ActionScript, so we'll pass on this one as well. Considering the other formats listed above, for our application, we prefer e4X XML. An e4X expression newsFeed.lastResult.channel.item is all you need to populate the XMLListCollection with news headlines. This XMLListCollection will be used as the dataProvider of the news DataGrid.

As usual, we'll separate the code that merely starts the application from the FinancialNews view ( see Listing 1).

<?xml version="1.0" encoding="utf-8"?>
<!--news1.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="*" >
     <FinancialNews1 id="fn"/>
</mx:Application>

Our newsFeed will initiate the following request from the creationComplete event:

     newsFeed.send({s:"ADBE"});

As part of the send method, Flex converts the object's property into a GET URL parameter using the object's properties as parameter names. Here s:"ADBE" will be concatenated in the form of "?s=ADBE" to the http://finance.yahoo.com/rss/headline specified by the news destination. Since RSS data can be verbose, we'll set the relevant columns of the grid with wordWrap="true" and the height of the Grid row to be flexible:
variableRowHeight="true".

Introducing Item Renderers
To make the data grid's column Link open a news story in a separate browser window, we need to customize the way of displaying (rendering) the cells of this column. We will use the so-called itemRenderer in the <mx:DataGridColumn> tag (see more samples of using item renderers in Chapters 8 and 9). There are two major kinds of item renderers:

•  drop-in, which is an ActionScript class that you specify as the value of the itemRenderer of any list-derived control.

•  inline, where you use an <mx:Component> tag to define a renderer component inside the <mx:itemRenderer> element.

To create an inline renderer, we'd need to change:

<mx:DataGridColumn headerText="Link" width="130" dataField="link" wordWrap="true"/>

into the following code:

<mx:DataGridColumn headerText="Link" width="130">
   <mx:itemRenderer>
     <mx:Component>
       <mx:LinkButton label="{data.link}" click="navigateToURL(new
         URLRequest(data.link), '_blank')"/>
     </mx:Component>
   </mx:itemRenderer>
</mx:DataGridColumn>

The ActionScript function flash.net.navigateToURL opens or replaces a window in the Flash Player's container application - opens it, in our case, in a blank browser.

While inline renderers excel in readability, drop-in renderers are reusable. If you expect to have links with similar presentation and functionality you may decide to create a class out of it.

Let us introduce the write-only security property for the FinancialView2 class. Please note that we provide a setter method to send a newsFeed request every time the security (stock symbol) is updated:

public function set security(value:String):void {
     newsFeed.send({s:value});
}


More Stories By Victor Rasputnis

Dr. Victor Rasputnis is a Managing Principal of Farata Systems. He's responsible for providing architectural design, implementation management and mentoring to companies migrating to XML Internet technologies. He holds a PhD in computer science from the Moscow Institute of Robotics. You can reach him at [email protected]

More Stories By Yakov Fain

Yakov Fain is a Java Champion and a co-founder of the IT consultancy Farata Systems and the product company SuranceBay. He wrote a thousand blogs (http://yakovfain.com) and several books about software development. Yakov authored and co-authored such books as "Angular 2 Development with TypeScript", "Java 24-Hour Trainer", and "Enterprise Web Development". His Twitter tag is @yfain

More Stories By Anatole Tartakovsky

Anatole Tartakovsky is a Managing Principal of Farata Systems. He's responsible for creation of frameworks and reusable components. Anatole authored number of books and articles on AJAX, XML, Internet and client-server technologies. He holds an MS in mathematics. You can reach him at [email protected]

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.


IoT & Smart Cities Stories
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...
Nicolas Fierro is CEO of MIMIR Blockchain Solutions. He is a programmer, technologist, and operations dev who has worked with Ethereum and blockchain since 2014. His knowledge in blockchain dates to when he performed dev ops services to the Ethereum Foundation as one the privileged few developers to work with the original core team in Switzerland.
René Bostic is the Technical VP of the IBM Cloud Unit in North America. Enjoying her career with IBM during the modern millennial technological era, she is an expert in cloud computing, DevOps and emerging cloud technologies such as Blockchain. Her strengths and core competencies include a proven record of accomplishments in consensus building at all levels to assess, plan, and implement enterprise and cloud computing solutions. René is a member of the Society of Women Engineers (SWE) and a m...
Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
Whenever a new technology hits the high points of hype, everyone starts talking about it like it will solve all their business problems. Blockchain is one of those technologies. According to Gartner's latest report on the hype cycle of emerging technologies, blockchain has just passed the peak of their hype cycle curve. If you read the news articles about it, one would think it has taken over the technology world. No disruptive technology is without its challenges and potential impediments t...
If a machine can invent, does this mean the end of the patent system as we know it? The patent system, both in the US and Europe, allows companies to protect their inventions and helps foster innovation. However, Artificial Intelligence (AI) could be set to disrupt the patent system as we know it. This talk will examine how AI may change the patent landscape in the years to come. Furthermore, ways in which companies can best protect their AI related inventions will be examined from both a US and...
Bill Schmarzo, Tech Chair of "Big Data | Analytics" of upcoming CloudEXPO | DXWorldEXPO New York (November 12-13, 2018, New York City) today announced the outline and schedule of the track. "The track has been designed in experience/degree order," said Schmarzo. "So, that folks who attend the entire track can leave the conference with some of the skills necessary to get their work done when they get back to their offices. It actually ties back to some work that I'm doing at the University of San...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things'). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing. IoT is not about the devices, its about the data consumed and generated. The devices are tools, mechanisms, conduits. This paper discusses the considerations when dealing with the...
Bill Schmarzo, author of "Big Data: Understanding How Data Powers Big Business" and "Big Data MBA: Driving Business Strategies with Data Science," is responsible for setting the strategy and defining the Big Data service offerings and capabilities for EMC Global Services Big Data Practice. As the CTO for the Big Data Practice, he is responsible for working with organizations to help them identify where and how to start their big data journeys. He's written several white papers, is an avid blogge...