What is a service-oriented architecture (SOA)? Service-Oriented Architecture (SOA) is a component model that links different functional units of the application to the contract between these services. The interface is defined in a neutral manner, which should be independent of the hardware platform, operating system, and programming language that implements the service. This allows services to construct in a variety of such systems to interact in a unified and universal manner. This feature having a neutral interface definition (no forced binding to a specific implementation) is called a loosening between services. There are two points of loosely coupled systems, one is its flexibility, and the other is that it can continue to exist when the internal structure of each service of the entire application is gradually changed. On the other hand, it is impossible to connect the interface between the different components of the application, and it is very fragile when some or the entire application needs to make some form of changes. The need for loosely coupled systems is derived from business applications to become more flexible according to business, to accommodate changing environments, such as regular changes, business level, business focus, partnership, industry status, etc. Business-related factors, which will even affect the nature of the business. We call the business that can be flexibly adapt to the environmental changes in-Demand service, in on-demand services, once you need, you can make the necessary changes to the way you complete or perform tasks. Although the service-oriented architecture is not a new thing, it is a more traditional alternative model of object-oriented model, and the object-oriented model is tight, and there is more than 20 years. Although SOA-based systems do not exclude the use of object-oriented design to build a single service, its overall design is a service-oriented. Since it takes into account the object within the system, although SOA is object-based, it is not an object-oriented. The difference is that the interface itself. One typical example of the SOA system prototype is a common object requesting agency architecture, CORBA. It has already seen a long time, and its definition is similar to SOA. However, the current SOA has different because it relies on some updated progress, which is based on Extensible Markup Language, XML. The interface is described using an XML-based language (called Web Services Definition, WSDL)), the service has been transferred to a more dynamic and more flexible interface system, non-previous CORBA interface description language (Interface Definition language, IDL is comparable. Web services are not the only way to implement SOA. The previous CORBA is another way, which has a message-oriented middleware system, such as the IBM's MQSeries. But in order to establish an architecture model, you need is not just a service description. You need to define how the entire application executes its workflow between services. You especially need to find the conversion point between the operations of the business and the operations of the software used in the business. Therefore, SOA should be able to associate business processes with their technical processes and map the relationship between the two.
For example, the operation of payment to the vendor is a business process, and your part database is updated to include the new supply of goods is a technical process. Thus, workflows can also play an important role in the design of SOA. In addition, the workflow of dynamic services can not only include operations between sectors, or even operate with external partners that do not control you. Therefore, in order to improve efficiency, you need to define how the relationships should be recognized, this policy often uses the form of service-class agreements and operational strategies. Finally, all of this must be in a trust and reliable environment, as expected, based on the agreed terms, based on the agreement. Therefore, security, trust and reliable messaging should play an important role in any SOA. What can I do with a service-oriented architecture? The needs of SOA come from need to make the business IT system more flexible to adapt to changes in the business. By allowing strong definitions and still flexible specific implementations, IT systems can use existing systems, but also ready to make some changes to meet their interaction between them. Let's take a specific example. A clothing retail organization has 500 international chains, which often need to change the design to catch up with fashion. This may mean not only need to change style and color, or even need to replace cloth, manufacturers, and deliverable products. If the retailers and manufacturers are not compatible, the replacement from a vendor to another may be a very complex software process. By using the WSDL interface flexibility in operation, each company can maintain their existing systems, but only match the WSDL interface and develop new service-level agreements, so they do not have to fully refactor their software systems. This is the level of business, that is, they change their partners, and all business operations are basically unchanged. Here, the business interface can make a little change, while the internal operation does not need to change, which is done, just to work with external partners. Another form is internal change. In this change, the retail organization now decides that it will rent some places in the chain retail store to small stores who specialize in popular clothes, which can be seen as a store in the store (Store- In-store) business model. Here, although most of the company's business operations remain unchanged, they now need new internal software to handle such a rental arrangement. Although the internal software system can withstand a comprehensive overhaul, they need to do a big impact on the interaction with the existing supplier system while doing. In this case, the SOA model remains uncovered, and the internal implementation has changed. Although new aspects can be added to the SOA model to join the duties of new rental arrangements, the normal retail management system can continue as usual. In order to continuing internal changes, IT managers may find that new configurations can also be used in another way, such as renting a poster for advertising. Here, new business proposals are derived from a flexible SOA model in new design. This is a new achievement from the SOA model, and is still a new opportunity, and such new opportunities may not have it before. Vertical changes are also possible, in this change, retailers are completely transformed from selling their own clothing to a place to rent in the store. If vertical changes are completely started from the bottom, there will be a significant change in the SOA model structure, and there may be new systems, software, processes, and relationships with one of them. In this case, the advantage of the SOA model is that it considers problems from the perspective of business operations and processes rather than from the perspective of applications and programs, which makes business management to clearly determine what needs to be added according to the operation of the business. Or delete. The software system can then be constructed to be suitable for business processing, rather than other means they often see on many existing software platforms.
