|By Jinsong Yang||
|January 14, 2009 09:59 PM EST||
Since its emergence, Web Service technology has gone a long way towards perfecting itself and finding its right application in the real world. With the maturity of the specifications, Web Service technology, with its power of interoperability, is now the major enabling technology of SOA, which is being adopted by more and more enterprises to build their application integration infrastructure.
Developing Web Services involves a variety of technologies, XML processing, SOAP, and WSDL, to name a few. Luckily, there are frameworks that target handling theses kinds of middleware functions, freeing up developers to focus on the business logic.
Nowadays, many Web Service frameworks exist for all kinds of programming languages. Some of them are open source, others are commercially available. Some examples of such frameworks are Apache Axis and Axis2, WS02 Web Services Framework (WSF), Java Web Services Development Pack (GlassFish), JBossWS, and XINS.
Being one of the Web Service frameworks for Java, Apache CXF is an open source framework developed by the Apache Software Foundation. It's a continuation and merging of two open source projects, Codehaus' XFire project and ObjectWeb's Celtix project. When this was written, the stable version was 2.0.
CXF enables the creation of Web Services using Java technologies. It supports a variety of Web Service standards including WS-I Basic Profile 1.0, WS-Addressing, WS-Policy, WS-ReliableMessaging, and WS-Security.
CXF supports transport protocols like HTTP and JMS. The messaging formats supported include SOAP, XML, RESTFul HTTP, and CORBA. Besides JAXB data binding, it also supports Aegis binding.
CXF is JAX-WS (JSR 224)-compliant and version 2.0 has passed the TCK for JAX-WS 2.0. It makes intensive use of Java 5 annotations and so requires JDK/JRE 5.0 and above.
CXF leverages the Spring application framework for bean management. Endpoints and service clients can be managed as Spring beans.
In the first section of this article, a step-by-step Web Service example using CXF is presented. Some of CXF's basic features are revealed while going through the steps of creating the example. Then we'll touch on some of the unique features of CXF, including RESTful service support and Spring integration. At the end, a brief performance test will compare CXF with JBossWS and the JAX-WS Reference Implementation (RI).
An Example: Getting Movie Show Times
In this example, we'll build a Web Service that lets a client system query for movie show times using the ZIP code entered by a user. For demonstration purposes, most of the irrelevant details are ignored.
CXF supports both code-first development and contract-first development. While code-first development is a handy feature, and most developers find it more straightforward and easier to get start with, it has a vital weakness.
There are several reasons for this. First, a key aspect in successfully developing Web Services is to determine its granularity. Considering the fact that the major application of Web Services is to implement SOA solution at a really high level (e.g., at the enterprise level), the granularity couldn't be too small. In contrast are the Java classes and methods, which tend to be very fine-grained, and are often designed at the very low level (i.e. the class level). Secondly, Web Services bare the nature of language neutral. Building a service from a specific language (like Java) and transforming it into a language-neutral form through some tools would, in some cases, bring over language-specific features, which will degrade the language-neutral nature, thus hurt the interoperability, of the service. Lastly, from a design point of view, service-oriented principles are significantly different from object-oriented paradigms. Although an individual service might be realized using OO principles and techniques, the interaction between services rarely using any of them.
Due to the aforementioned reasons, code-first development will never let you get to the spirit of service-oriented development because developing in Java code and developing in WSDL requires different mindset. Developing with Java code-first and avoiding WSDL as much as possible will guarantee that you will build mediocre software at the best. This is especially true when it comes to designing and developing a SOA solution rather than just individual services.
With that said, let's start with contract-first development for our example, the first step of which is to create the contract - the WSDL document that describes the service.
Listing 1 shows a segment of the WSDL document. In this document a service called MovieService is defined. This service has only one operation GetShowtimesForZip. The input of this operation is a message containing the ZIP code that the user entered, and the response is a list of theaters and movies along with show times.
The types are defined in a separated XML Schema document and are imported using <xsd:import> statement. The schema document isn't listed here to avoid lengthy text.
Nothing is really special about this WSDL document. Let's now generate the service interface and the service endpoint interface (SEI) from the WSDL document.
Service and Service Endpoint Interfaces
With the WSDL document ready, our next step is to generate server-side Java code from it. CXF provides a tool called wsdl2java that can be used to generate fully annotated Java code from a WSDL document. This tool operates according to the JAX-WS rules for WSDL <--> Java mapping, and its data binding mechanism conforms to JAXB (JSR 22). The tool comes with a set of optional arguments that allow control of the behavior of the tool.
The WSDL document used to generate the Java code has to have a valid portType element, but it doesn't require a binding element or a service element.
The simplest form of running the tool on the command line is listed in Listing 2.
You can specify the package of the generated code using the -p option as shown in Listing 3.
JAX-WS defines an XML-based binding language that can be used to customize the WSDL to Java bindings. The wsdl2java tool implements this feature using the -b option. Listing 4 shows how to specify a JAX-WS binding file for customization.
You can ask the tool to generate an Ant build file for use in your application. To do so, use the -ant option as shown in Listing 5:
Or you can define your own Ant macro. A sample of such a macro is included in the CXF distribution. Listing 6 shows a modified version of it.
|kuldeep_saini83 08/29/09 08:33:00 PM EDT|
|yogesh 10/06/08 02:27:38 PM EDT|
What sort of WebRTC based applications can we expect to see over the next year and beyond? One way to predict development trends is to see what sorts of applications startups are building. In his session at @ThingsExpo, Arin Sime, founder of WebRTC.ventures, will discuss the current and likely future trends in WebRTC application development based on real requests for custom applications from real customers, as well as other public sources of information,
Mar. 27, 2017 12:30 AM EDT Reads: 818
China Unicom exhibit at the 19th International Cloud Expo, which took place at the Santa Clara Convention Center in Santa Clara, CA, in November 2016. China United Network Communications Group Co. Ltd ("China Unicom") was officially established in 2009 on the basis of the merger of former China Netcom and former China Unicom. China Unicom mainly operates a full range of telecommunications services including mobile broadband (GSM, WCDMA, LTE FDD, TD-LTE), fixed-line broadband, ICT, data communica...
Mar. 27, 2017 12:00 AM EDT Reads: 3,314
My team embarked on building a data lake for our sales and marketing data to better understand customer journeys. This required building a hybrid data pipeline to connect our cloud CRM with the new Hadoop Data Lake. One challenge is that IT was not in a position to provide support until we proved value and marketing did not have the experience, so we embarked on the journey ourselves within the product marketing team for our line of business within Progress. In his session at @BigDataExpo, Sum...
Mar. 26, 2017 11:15 PM EDT Reads: 2,866
With the introduction of IoT and Smart Living in every aspect of our lives, one question has become relevant: What are the security implications? To answer this, first we have to look and explore the security models of the technologies that IoT is founded upon. In his session at @ThingsExpo, Nevi Kaja, a Research Engineer at Ford Motor Company, will discuss some of the security challenges of the IoT infrastructure and relate how these aspects impact Smart Living. The material will be delivered i...
Mar. 26, 2017 09:45 PM EDT Reads: 2,033
Apache Hadoop is emerging as a distributed platform for handling large and fast incoming streams of data. Predictive maintenance, supply chain optimization, and Internet-of-Things analysis are examples where Hadoop provides the scalable storage, processing, and analytics platform to gain meaningful insights from granular data that is typically only valuable from a large-scale, aggregate view. One architecture useful for capturing and analyzing streaming data is the Lambda Architecture, represent...
Mar. 26, 2017 08:30 PM EDT Reads: 6,110
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningf...
Mar. 26, 2017 07:45 PM EDT Reads: 9,582
Your homes and cars can be automated and self-serviced. Why can't your storage? From simply asking questions to analyze and troubleshoot your infrastructure, to provisioning storage with snapshots, recovery and replication, your wildest sci-fi dream has come true. In his session at @DevOpsSummit at 20th Cloud Expo, Dan Florea, Director of Product Management at Tintri, will provide a ChatOps demo where you can talk to your storage and manage it from anywhere, through Slack and similar services ...
Mar. 26, 2017 06:45 PM EDT Reads: 4,258
SYS-CON Events announced today that Ocean9will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Ocean9 provides cloud services for Backup, Disaster Recovery (DRaaS) and instant Innovation, and redefines enterprise infrastructure with its cloud native subscription offerings for mission critical SAP workloads.
Mar. 26, 2017 06:30 PM EDT Reads: 2,039
The taxi industry never saw Uber coming. Startups are a threat to incumbents like never before, and a major enabler for startups is that they are instantly “cloud ready.” If innovation moves at the pace of IT, then your company is in trouble. Why? Because your data center will not keep up with frenetic pace AWS, Microsoft and Google are rolling out new capabilities In his session at 20th Cloud Expo, Don Browning, VP of Cloud Architecture at Turner, will posit that disruption is inevitable for c...
Mar. 26, 2017 05:00 PM EDT Reads: 2,132
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
Mar. 26, 2017 02:30 PM EDT Reads: 1,774
SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, 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 dea...
Mar. 26, 2017 02:15 PM EDT Reads: 4,374
SYS-CON Events announced today that Technologic Systems Inc., an embedded systems solutions company, will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Technologic Systems is an embedded systems company with headquarters in Fountain Hills, Arizona. They have been in business for 32 years, helping more than 8,000 OEM customers and building over a hundred COTS products that have never been discontinued. Technologic Systems’ pr...
Mar. 26, 2017 02:00 PM EDT Reads: 3,387
Mar. 26, 2017 01:45 PM EDT Reads: 8,507
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
Mar. 26, 2017 01:45 PM EDT Reads: 1,838
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, 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.
Mar. 26, 2017 01:15 PM EDT Reads: 2,126
SYS-CON Events announced today that Loom Systems will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2015, Loom Systems delivers an advanced AI solution to predict and prevent problems in the digital business. Loom stands alone in the industry as an AI analysis platform requiring no prior math knowledge from operators, leveraging the existing staff to succeed in the digital era. With offices in S...
Mar. 26, 2017 12:45 PM EDT Reads: 1,320
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 20th Cloud Expo, which will take place on June 6-8, 2017 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 add...
Mar. 26, 2017 12:30 PM EDT Reads: 1,133
SYS-CON Events announced today that T-Mobile will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...
Mar. 26, 2017 11:00 AM EDT Reads: 2,212
In his session at @ThingsExpo, Eric Lachapelle, CEO of the Professional Evaluation and Certification Board (PECB), will provide an overview of various initiatives to certifiy the security of connected devices and future trends in ensuring public trust of IoT. Eric Lachapelle is the Chief Executive Officer of the Professional Evaluation and Certification Board (PECB), an international certification body. His role is to help companies and individuals to achieve professional, accredited and worldw...
Mar. 26, 2017 10:45 AM EDT Reads: 635
SYS-CON Events announced today that Infranics will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Since 2000, Infranics has developed SysMaster Suite, which is required for the stable and efficient management of ICT infrastructure. The ICT management solution developed and provided by Infranics continues to add intelligence to the ICT infrastructure through the IMC (Infra Management Cycle) based on mathemat...
Mar. 26, 2017 10:15 AM EDT Reads: 3,019