The handleHolidayRequest(..) method is the primary method of the handle method passed with the incoming XML message element. The @RequestPayload note indicates that the holidayRequest parameter should be mapped to the payload of the request message. We use XPath expressions to retrieve string values from XML messages and convert those values to Date objects using a SimpleDateFormat. With these values, we call a method for business service. Typically, this causes a database transaction to start and some records in the database to change. Finally, we define an empty return type that tells Spring-WS that we do not want to send a reply message. If we had wanted a reply message, we could have returned a JDOM element that represents the payload of the reply message. The body of the SOAP message contains two elements at the same level, the elements with the tags num1 and num2. Each element is a child of the soapenv:Body element. The glaring omission is the name of the operation, for example, add. This name may appear instead, by .B. in the request URL: the wsimport utility generates code from a WSDL document that directly supports client calls to a Web service. The same code can be used with some customizations to program a service.
This section illustrates this with a simple example. Finally, you need an easy way to test your web service. The ASMX runtime provides documentation and a help page for this purpose. However, the problem with the default page is that you may still be calling ?wsdl on the ASMX endpoint. And this would still automatically make the WSDL derived from the current implementation of the web service and not use your predefined WSDL. WSCF takes the route that it adds a new custom help page that looks and feels like the original, but disables the ?wsdl feature completely. Since you`re starting from the WSDL into the contract world, you don`t want the WSDL to be available through the endpoint (although this is technically possible). These two types of contracts are also known as CPP and document-based contracts. The RPC-style WS contract is assumed to be operation-based, and a document-style WS contact conforms to the XML/XSD schema. For example, Java Spring-WS supports document-based Web services and can then automatically generate the WSDL from the schema. The terms “abstract description” and “concrete description” come from the W3C, the standards body responsible for developing most of the technologies covered in this book. From an implementation perspective, abstract description is also very concrete, as it ultimately forms the actual physical interface with which service consumption programs ultimately connect.
This article is definitely not the right place to discuss all the pros and cons of service orientation. But we can cling to the fact that service orientation is a new level of abstraction in the world of software design and development, beyond objects. Just to be clear, these are not objects vs. services, they are just services with objects, because you can implement a service with objects, but you don`t have to. For this article, a service is a program that can accept messages and send messages by itself – no more and no less. However, developers need more if they want to achieve interoperability between systems on different and heterogeneous platforms. It`s not just about “wiring” a connection between object A in .NET and object B in Java. A good software architect (no matter what that means) wants so much implementation details and internal Java applications before the.
NET client and all other potential consumers of the application. Indeed, developers have learned a lot about deploying software systems that are too tight to couple. Of course, sometimes a close coupling and intimate knowledge of all the other “objects” is necessary and a good thing. But at least when developers talk about enterprise application integration (EAI) scenarios, all parties try to minimize dependencies between all associated systems, allowing for the greatest possible flexibility in assembling application architectures. Welcome to the world of service orientation. There are essentially two philosophies for contract-driven design: code-based design and schema-based design. Code-based means that a developer always uses a CLS-compatible programming language to write the interface of their web service. In addition, they use a number of specific XML and SOAP. NET to achieve their goals.
I think it`s a bit dangerous because it always focuses on objects and .NET BCL. Also, it doesn`t prevent a developer from. NET idiosyncrasies such as a dataset. The add element (line 1) now acts as a wrapper for the argument elements, in this case num1 and num2. The encapsulated convention, unofficial but dominant in SOAP frameworks, gives a document-style service the appearance of an RPC-style service, at the message level. The document style always has the advantage of a complete XML schema that enters messages. In Java, as in DotNet, the default style of any SOAP service is an encapsulated document. Therefore, a service such as RandService, which contains only the annotation @WebService, is elegantly included in a document.
This style is often shortened to encapsulated doc/lit: Encapsulated document style with literal encoding. To start using the WSDL Wizard, you must add the two existing XSD files for the data and message types to your contract metadata project. Based on the messages you have designed, you now want to configure the interface. Simply right-click the UgMessages.xsd file in your Visual Studio. NET and select Create WSDL Interface Description. in the context menu (see Figure 4). The WSDL WSCF Wizard opens with a Start screen. On the next page, the user must provide basic information about the interface, including the name, XML namespace, and an optional comment. On the next page of the wizard, you can add additional message XML schema files. Because sometimes you can start with one file right away, but you actually have different types of message types spread across multiple XSD files (see Figure 5). To see how code generation works with WSCF, it`s time to think like a web services developer.
The code generation process for the client application is analogous. Because it is so easy to right-click on the WSDL and select Generate Web Service Code. In Figure 9, you can select several options for code generation. You choose everything to have one. NET representation of your data, messages, and interface contracts. After you finish generating code, a set of files is added to the Web service project (Figure 10). Let`s take a look at all the features that WSCF provides in terms of code generation. Publish the service, .B. with an endpoint or web server such as Tomcat or Jetty.
The literal schemas.xmlsoap.org/soap/http is an HTTP transport. Web service contracts can vary in content, depth, and complexity. To fully understand the intricacies and design possibilities of structuring web service contracts, we must first disassemble this structure to understand its individual parts and the mechanics that make these parts work together. The first major phase has been completed. You have now configured your XSD and WSDL. Now it`s time to get to the real code. You must create a CLS-compliant representation of the data, message, and interface contract. Of course, you can use wsdl.exe for this task because it is part of the .NET Framework SDK and provides simple code generation features. But there are two main caveats: it`s not fully integrated with the IDE (although there`s the infamous Add Web Reference dialog box) and, more importantly, it doesn`t generate well enough.
NET code. There are formal terms used to represent the three basic parts we just covered. As shown in Figure 4.2, the “what” part of the Web service contract is called an abstract description. This party is essentially responsible for expressing the public interface (or API) of the contract. The input message precedes the output message which indicates that the template is a request/response. If the order were reversed, the pattern would be Solicitation/Response. The term input must be understood from the point of view of the service: an input message enters the service and an output message leaves the service. Each input and output element names the message defined in a message section, which in turn refers to an XML schema complexType. As a result, each operation can be linked to the entered messages that make up the operation. In the above spring configuration, we defined the Web service endpoint. The portType is particularly interesting because it characterizes the service in terms of operations and not just messages. Operations consist of one or more messages that are exchanged according to a specified pattern.
The two areas that would be of immediate interest to a programmer writing a client for a service would be the portType and the service. The PortType section informs the programmer of the calls that can be made against the service, and the service section gives the service endpoint the URL through which the service can be reached. . . .