In the last article, we introduced the "object-oriented software technology". Object-oriented technology has spawned components technology, component technology provides improved methods for software development, which makes challenges to outdated ideas. These principles have jointly established a major new technological trend. Components are based on the basis of technology change, just like objects that are previously exhibited. We will discuss component technology after brief introduction to the unique principle of components. Software Skills to the next level requires that the basic principles of system ideas, software processing and technical tools have changed. The next primary technical range-component (or component) contains the key principle to solve the current critical software problem. Component's method introduces a close-related technique and process. Component technology introduces an improved idea for generating business outcomes. In order to generate business effects, components introduce a skillful idea. These component principles include: The lower layer constructive software mode software architecture of the assembly can be considered an object or other software technology based on the comparative component of the component's lower-layer construction software mode software architecture. There are four principles of differentiate components and other previous technologies: encapsulation, polymorphism, late connection, and security (Safety). This list is repeated with object-oriented, except that it deletes this focus on inheritance. In component idea, inheritance is closely coupled, white-box relationship, which is not suitable for most forms of packaging and reuse. Instead, the component replaces the inheritance from them by calling other objects and components. In the component terminology, these calls are called delegations. "It is equipped with each part, and it is placed in another, and it is necessary to build your own outline like a carpenter to build a house. Everything must be built, and all partially combinedly formed all ..." - Henri Matisse Practices, all components have specifications corresponding to their implementation. This specification defines the package of components (for example, it is a common interface provided by other components). Repeated use of component specification is a form of polymorphism, which is highly encouraged. Ideally, component specifications are local or global standards, which are widely reused in systems, enterprises or industries. Components use synthesis to establish systems. In synthesis, two or more components are integrated to create a larger entity, and it may be a new component, component framework, or whole system. Synthesis is the integration of components. The combined components are jointly obtained from the elements components. If the component meets the specifications of the client calls and services, they do not need additional code to implement interactive operations (Interoperate). This is generally referred to as a plug-and-play. This is a similarity in the post-connection when executed during runtime. For example, a client component can discover component servers (similar to CORBA Trader services) through an online directory. After the components meet the client and the service interface specification, it is possible to establish a runtime binding between each other, and seamlessly interact with the lower construction of the assembly. In the perfect situation, all components will fully meet their specifications and liberate from all defects. The successful operation and interaction of components depends on many internal and external factors. Security (Safety) properties may be useful because it minimizes the defects of all classes in a component environment. As society is increasingly detrimental to software technology, safety has become an important legal stakeholder, and is one of the most important issues in computer science research.
For example, the Garbage Collection feature of Java guarantees the security of memory, or is liberated from memory allocation defects (which is problematic in C programs). Other types of security include type security (Type Safety, compatibility with data type) and module security, controlling software extension and component synthesis.
The lower part of the component of the component has evolved to the form of the undercurries. The main platform vendors pin their future on the component product line. In particular, Microsoft, Sun Microsystems, IBM and CORBA associations have established important components under the following construction through a large number of technical and market investment. The lower construction of these components (Microsoft's Java Enterprise JavaBeans of Microsoft contains CORBAs) are the main lower constructs that compete with object-oriented enterprise applications in the industry. Interestingly, these technologies have expanded their interaction between XML, Web services and other enterprise applications. Microsoft fully repairs the lower construction of your component in the current .NET product suite. Microsoft .NET product suite focuses on the development and deployment of enterprise applications and distributed services. Although it mixes a large number of new code, it also contains Microsoft's previous distributed development platform - Microsoft Distributed Network Architecture (DNA) and Similar Microsoft Transaction Server (MTS), Microsoft SQL Server and other distributed universal object models (DCOM) and many successful products and techniques for long-term existing common object models (COM) / COM -. The existing .NET kit updated these products in the integrated corporate product suite, increasing new support for XML data, web services, and a large number of improved development environments. Microsoft .NET is a tangible evidence that the software industry needs to verify, which proves that Microsoft will play a major role in the world that is foreseeable future. The Java language invented by the solar microsystems is the continuous evolution of programming language characteristics, lower constructors, and related class libraries. Java language technology has attracted great turmoil in the industry and is supported by independent developers. The extension of Java-Beans and Enterprise JavaBeans has established an evolutionary component model that competes with COM and ActiveX in cross-platform applications. Enterprise Javabeans and IBM San Francisco projects are using Java Remote Method Call (RMI) to make distributed computing, which is one of several patented lower constructs that Java language programmers can use. Recently, the Java language has included RMI on the INTERNET Internet Internal ORB Protocol (IIOP), which allows Java to interact with other distributed components in programming languages with CORBA IDL interfaces. Although the lower structure of the patented Java language is indeed convenient for programmers, in order to interact with other programming languages, they need additional complexity, especially in partial use of Java local interface (JNI) programming languages other than Java. In the case of the program. This has a major obstacle to a common project because it slows down the integration of traditional technology and transfiguration, and these are common for server applications. In many organizations of understanding the Internet, the Java application server has replaced the role of CORBA. CORBA lacks direct support for scalability, reliability and maintainability. These capabilities are now standard characteristics supported by most Java application servers. The lower structure of the component has an important impact on software development. In many ways, these lower structures are moving toward the direction of the mainstream development platform. Because they have become interactive (through CORBA IIOP), the relationship between the lower constructor is well understood. They are far more than their patented differences. The selection of the lower construct is to discuss the most problem, but for the implementation of the component, its importance is the lowest. For common developers, the most important issue will encounter after selecting the lower part. These issues include how to master the design of this technology, how to architecture system, how to coordinate the development of each other. The design mode software design mode of the component software is composed of a common body that can be applied to software knowledge constructed under all components.
