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Service Locator Pattern
The service locator pattern is a design pattern used in software development to encapsulate the processes involved in obtaining a service with a strong abstraction layer. This pattern uses a central registry known as the "service locator", which on request returns the information necessary to perform a certain task. Proponents of the pattern say the approach simplifies component-based applications where all dependencies are cleanly listed at the beginning of the whole application design, consequently making traditional dependency injection a more complex way of connecting objects. Critics of the pattern argue that it is an anti-pattern which obscures dependencies and makes software harder to test. Advantages * The "service locator" can act as a simple run-time linker. This allows code to be added at run-time without re-compiling the application, and in some cases without having to even restart it. * Applications can optimize themselves at run-time by selectively adding and remo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Pattern (computer Science)
In software engineering, a software design pattern or design pattern is a general, reusable solution to a commonly occurring problem in many contexts in software design. A design pattern is not a rigid structure to be transplanted directly into source code. Rather, it is a description or a template for solving a particular type of problem that can be deployed in many different situations. Design patterns can be viewed as formalized best practices that the programmer may use to solve common problems when designing a software application or system. Object-oriented design patterns typically show relationships and interactions between classes or objects, without specifying the final application classes or objects that are involved. Patterns that imply mutable state may be unsuited for functional programming languages. Some patterns can be rendered unnecessary in languages that have built-in support for solving the problem they are trying to solve, and object-oriented patterns are no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Development Tool
A programming tool or software development tool is a computer program that is used to develop another computer program, usually by helping the developer manage computer files. For example, a programmer may use a tool called a source code editor to edit source code files, and then a compiler to convert the source code into machine code files. They may also use build tools that automatically package executable program and data files into shareable packages or install kits. A set of tools that are run one after another, with each tool feeding its output to the next one, is called a toolchain. An integrated development environment (IDE) integrates the function of several tools into a single program. Usually, an IDE provides a source code editor as well as other built-in or plug-in tools that help with compiling, debugging, and testing. Whether a program is considered a development tool can be subjective. Some programs, such as the GNU compiler collection The GNU Compile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abstraction Layer
In computing, an abstraction layer or abstraction level is a way of hiding the working details of a subsystem. Examples of software models that use layers of abstraction include the OSI model for network protocols, OpenGL, and other graphics libraries, which allow the separation of concerns to facilitate interoperability and platform independence. In computer science, an abstraction layer is a generalization of a Conceptual model (computer science), conceptual model or algorithm, away from any specific implementation. These generalizations arise from broad similarities that are best encapsulated by models that express similarities present in various specific implementations. The simplification provided by a good abstraction layer allows for easy reuse by distilling a useful concept or design pattern so that situations, where it may be accurately applied, can be quickly recognized. Just composing lower-level elements into a construct doesn't count as an abstraction layer unless it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-pattern
An anti-pattern in software engineering, project management, and business processes is a common response to a recurring problem that is usually ineffective and risks being highly counterproductive. The term, coined in 1995 by computer programmer Andrew Koenig (programmer), Andrew Koenig, was inspired by the book ''Design Patterns'' (which highlights a number of design patterns in software development that its authors considered to be highly reliable and effective) and first published in his article in the ''Journal of Object-Oriented Programming''. A further paper in 1996 presented by Michael Ackroyd at the Object World West Conference also documented anti-patterns. It was, however, the 1998 book ''AntiPatterns'' that both popularized the idea and extended its scope beyond the field of software design to include software architecture and project management. Other authors have extended it further since to encompass environmental, organizational, and cultural anti-patterns. Definiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Run Time (program Lifecycle Phase)
Execution in computer and software engineering is the process by which a computer or virtual machine interprets and acts on the instructions of a computer program. Each instruction of a program is a description of a particular action which must be carried out, in order for a specific problem to be solved. Execution involves repeatedly following a " fetch–decode–execute" cycle for each instruction done by the control unit. As the executing machine follows the instructions, specific effects are produced in accordance with the semantics of those instructions. Programs for a computer may be executed in a batch process without human interaction or a user may type commands in an interactive session of an interpreter. In this case, the "commands" are simply program instructions, whose execution is chained together. The term run is used almost synonymously. A related meaning of both "to run" and "to execute" refers to the specific action of a user starting (or ''launching'' o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linker (computing)
A linker or link editor is a computer program that combines intermediate software build files such as object file, object and library (computing), library files into a single executable file such as a program or library. A linker is often part of a toolchain that includes a compiler and/or assembler (computing), assembler that generates intermediate files that the linker processes. The linker may be integrated with other toolchain development tool, tools such that the user does not interact with the linker directly. A simpler version that writes its Input/output, output directly to Computer memory, memory is called the ''loader'', though loader (computing), loading is typically considered a separate process. Overview Computer programs typically are composed of several parts or modules; these parts/modules do not need to be contained within a single object file, and in such cases refer to each other using symbol (computing), symbols as addresses into other modules, which are ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Separation Of Concerns
In computer science, separation of concerns (sometimes abbreviated as SoC) is a design principle for separating a computer program into distinct sections. Each section addresses a separate '' concern'', a set of information that affects the code of a computer program. A concern can be as general as "the details of the hardware for an application", or as specific as "the name of which class to instantiate". A program that embodies SoC well is called a modular program. Modularity, and hence separation of concerns, is achieved by encapsulating information inside a section of code that has a well-defined interface. Encapsulation is a means of information hiding. Layered designs or packaging by feature in information systems are another embodiment of separation of concerns (e.g., presentation layer, business logic layer, data access layer, persistence layer). Separation of concerns results in more degrees of freedom for some aspect of the program's design, deployment, or usage. Comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Run-time Error
Execution in computer and software engineering is the process by which a computer or virtual machine interprets and acts on the instructions of a computer program. Each instruction of a program is a description of a particular action which must be carried out, in order for a specific problem to be solved. Execution involves repeatedly following a " fetch–decode–execute" cycle for each instruction done by the control unit. As the executing machine follows the instructions, specific effects are produced in accordance with the semantics of those instructions. Programs for a computer may be executed in a batch process without human interaction or a user may type commands in an interactive session of an interpreter. In this case, the "commands" are simply program instructions, whose execution is chained together. The term run is used almost synonymously. A related meaning of both "to run" and "to execute" refers to the specific action of a user starting (or ''launching'' or ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependency Injection
In software engineering, dependency injection is a programming technique in which an object or function receives other objects or functions that it requires, as opposed to creating them internally. Dependency injection aims to separate the concerns of constructing objects and using them, leading to loosely coupled programs. The pattern ensures that an object or function that wants to use a given service should not have to know how to construct those services. Instead, the receiving " client" (object or function) is provided with its dependencies by external code (an "injector"), which it is not aware of. Dependency injection makes implicit dependencies explicit and helps solve the following problems: * How can a class be independent from the creation of the objects it depends on? * How can an application, and the objects it uses support different configurations? Dependency injection is often used to keep code in-line with the dependency inversion principle. In statically ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Testing
Software testing is the act of checking whether software satisfies expectations. Software testing can provide objective, independent information about the Quality (business), quality of software and the risk of its failure to a User (computing), user or sponsor. Software testing can determine the Correctness (computer science), correctness of software for specific Scenario (computing), scenarios but cannot determine correctness for all scenarios. It cannot find all software bug, bugs. Based on the criteria for measuring correctness from an test oracle, oracle, software testing employs principles and mechanisms that might recognize a problem. Examples of oracles include specifications, Design by Contract, contracts, comparable products, past versions of the same product, inferences about intended or expected purpose, user or customer expectations, relevant standards, and applicable laws. Software testing is often dynamic in nature; running the software to verify actual output ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependency Inversion Principle
In object-oriented design, the dependency inversion principle is a specific methodology for Coupling (computer programming), loosely coupled software Modular programming, modules. When following this principle, the conventional dependency (computer science), dependency relationships established from high-level, policy-setting modules to low-level, dependency modules are reversed, thus rendering high-level modules independent of the low-level module implementation details. The principle states: By dictating that high-level and low-level objects must depend on the same abstraction, this design principle the way some people may think about object-oriented programming. The idea behind points A and B of this principle is that when designing the interaction between a high-level module and a low-level one, the interaction should be thought of as an abstract interaction between them. This has implications for the design of both the high-level and the low-level modules: the low-level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
