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Service Abstraction
Service abstraction is a design principle that is applied within the service-orientation design paradigm so that the information published in a service contract is limited to what is required to effectively utilize the service The service contract should not contain any superfluous information that is not required for its invocation. Also that the information should be limited to the serviced contract (technical contract and the service level agreement) only, no other document or medium should be made available to the service consumers other than the service contract that contains additional service related information. Purpose A service contract that contains details about what it encapsulates (e.g., the logic, implementation and the technology used to build the service) may end up being used in a particular manner by providing the service consumer more knowledge about the working of the service. In the case of service-orientation, more knowledge is not necessarily better. There i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service-orientation
Service-orientation is a design paradigm for computer software in the form of Service (Systems Architecture), services. The principles of service-oriented design stress the separation of concerns in the software. Applying service-orientation results in units of software partitioned into discrete, autonomous, and network-accessible units, each designed to solve an individual concern. These units qualify as services. History of service-orientation principles and tenets Service-orientation has received a lot of attention since 2003 due to the benefits it promises. These include increased return on investment, organisational agility and interoperability as well as a better alignment between business and Information technology, IT. It builds heavily on earlier design paradigms and enhances them with standardisation, loose coupling and business involvement. The paradigm lost momentum in 2009; since 2014, renewed interest can be observed under the Microservices moniker. In technology, dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abstract Class
In object-oriented programming, a class defines the shared aspects of objects created from the class. The capabilities of a class differ between programming languages, but generally the shared aspects consist of state ( variables) and behavior ( methods) that are each either associated with a particular object or with all objects of that class. Object state can differ between each instance of the class whereas the class state is shared by all of them. The object methods include access to the object state (via an implicit or explicit parameter that references the object) whereas class methods do not. If the language supports inheritance, a class can be defined based on another class with all of its state and behavior plus additional state and behavior that further specializes the class. The specialized class is a ''sub-class'', and the class it is based on is its ''superclass''. Attributes Object lifecycle As an instance of a class, an object is constructed from a class via '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Patterns
''Design Patterns: Elements of Reusable Object-Oriented Software'' (1994) is a software engineering book describing software design patterns. The book was written by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, with a foreword by Grady Booch. The book is divided into two parts, with the first two chapters exploring the capabilities and pitfalls of object-oriented programming, and the remaining chapters describing 23 classic software design patterns. The book includes examples in C++ and Smalltalk. It has been influential to the field of software engineering and is regarded as an important source for object-oriented design theory and practice. More than 500,000 copies have been sold in English and in 13 other languages. The authors are often referred to as the ''Gang of Four'' (GoF). Development and publication history The book started at a birds-of-a-feather session at the 1990 OOPSLA meeting, "Towards an Architecture Handbook", where Erich Gamma and Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Hacking
A hacker is a person skilled in information technology who achieves goals and solves problems by non-standard means. The term has become associated in popular culture with a security hackersomeone with knowledge of bugs or exploits to break into computer systems and access data which would otherwise be inaccessible to them. In a positive connotation, though, hacking can also be utilized by legitimate figures in legal situations. For example, law enforcement agencies sometimes use hacking techniques to collect evidence on criminals and other malicious actors. This could include using anonymity tools (such as a VPN or the dark web) to mask their identities online and pose as criminals. Hacking can also have a broader sense of any roundabout solution to a problem, or programming and hardware development in general, and hacker culture has spread the term's broader usage to the general public even outside the profession or hobby of electronics (see life hack). Etymology The term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an application associated with the database. Before digital storage and retrieval of data have become widespread, index cards were used for data storage in a wide range of applications and environments: in the home to record and store recipes, shopping lists, contact information and other organizational data; in business to record presentation notes, project research and notes, and contact information; in schools as flash c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service Discoverability Principle
Discoverability is the degree to which something, especially a piece of content or information, can be found in a search of a file, database, or other information system. Discoverability is a concern in library and information science, many aspects of digital media, software and web development, and in marketing, since products and services cannot be used if people cannot find it or do not understand what it can be used for. Metadata, or "information about information", such as a book's title, a product's description, or a website's keywords, affects how discoverable something is on a database or online. Adding metadata to a product that is available online can make it easier for end users to find the product. For example, if a song file is made available online, making the title, name of the band, genre, year of release, and other pertinent information available in connection with this song means the file can be retrieved more easily. Organizing information by putting it into alpha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Of Service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc. In the field of computer networking and other packet-switched telecommunication networks, quality of service refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priorities to different applications, users, or data Traffic flow (computer networking), flows, or to guarantee a certain level of performance to a data flow. Quality of service is particularly important for the transport of traffic with special requirements. In particula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service Refactoring
Within the service-orientation design paradigm, Service Refactoring is a design pattern, which is applied to an existing service so that either the service logic or its implementation can be changed without affecting the service consumers. Rationale It is natural for a service to undergo changes for various reasons. The change could be required because the underlying implementation e.g. databases, legacy systems, etc. needs to be upgraded or simply because the original service logic was not making efficient use of memory. In other cases, the change could be initiated by the service consumers themselves. For example, with limited concurrent usage, the service performs as stated in its SLA, however, with an increase in its concurrent usage, the service is unable to fulfill its SLA, consequently the service needs to respond to the increasing performance demands from its service consumers.Jason BloomberThe Four Pillars of Service-Oriented Development nline Date accessed: 27 April 2010 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. It is one component of software, which also includes documentation and other intangible components. A ''computer program'' in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions. Therefore, source code may be translated to machine instructions using a compiler written for the language. (Assembly language programs are translated using an assembler.) The resulting file is called an executable. Alternatively, source code may execute within an interpreter written for the language. If the executable is requested for execution, then the operating system loads it into memory and starts a process. The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction. If the source code is request ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Paradigm
The concept of design paradigms derives from the rather ambiguous idea of paradigm originating in the sociology of science, which carries at least two main meanings: * As models, archetypes, or quintessential examples of solutions to problems. A 'paradigmatic design' in this sense, refers to a design solution that is considered by a community as being successful and influential. Usually success is associated to market share or some other measure of popularity, but this need not be the case. For instance, the eMate and other Apple Newton devices can be considered as paradigmatic because of their influence in subsequent designs, despite their commercial failure. * As sociological paradigms, a design paradigm is the constellation of beliefs, rules, knowledge, etc. that is valid for a particular design community. Here a paradigm is not a particular solution, but rather the underlying system of ideas that causes a range of solutions to be 'normal' or 'obvious'. A current example is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information Hiding
In computer science, information hiding is the principle of segregation of the ''design decisions'' in a computer program that are most likely to change, thus protecting other parts of the program from extensive modification if the design decision is changed. The protection involves providing a stable interface which protects the remainder of the program from the implementation (whose details are likely to change). Written in another way, information hiding is the ability to prevent certain aspects of a class or software component from being accessible to its clients, using either programming language features (like private variables) or an explicit exporting policy. Overview The term ''encapsulation'' is often used interchangeably with information hiding. Not all agree on the distinctions between the two, though; one may think of information hiding as being the principle and encapsulation being the technique. A software module hides information by encapsulating the informatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependency (computer Science)
Dependency, dependence, dependent or depend may refer to: Computer science * Dependency (computer science) or coupling, a state in which one object uses a function of another object * Data dependency, which describes a dependence relation between statements in a program * Dependence analysis, in compiler theory * Dependency (UML), a relationship between one element in the Unified Modeling Language * Dependency relation, a type of binary relation in mathematics and computer science. * Functional dependency, a relationship between database attributes allowing normalization. * Dependent type, in computer science and logic, a type that depends on a value * Hidden dependency, a relation in which a change in many areas of a program produces unexpected side-effects * Library dependency, a relationship described in and managed by a software dependency manager tool to mitigate dependency hell Economics * Dependant (British English) (Dependent - American English), a person who depen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
