|
Command Pattern
In object-oriented programming, the command pattern is a Behavioral pattern, behavioral Design pattern (computer science), design pattern in which an object is used to Information hiding, encapsulate all information needed to perform an action or trigger an event at a later time. This information includes the method name, the object that owns the method and values for the method parameters. Four terms always associated with the command pattern are ''command'', ''receiver'', ''invoker'' and ''client''. A ''command'' object knows about ''receiver'' and invokes a method of the receiver. Values for parameters of the receiver method are stored in the command. The receiver object to execute these methods is also stored in the command object by Object composition#Aggregation, aggregation. The ''receiver'' then does the work when the execute() method in ''command'' is called. An ''invoker'' object knows how to execute a command, and optionally does bookkeeping about the command execution. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Programming
Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and implemented in code). In OOP, computer programs are designed by making them out of objects that interact with one another. Many of the most widely used programming languages (such as C++, Java, and Python) support object-oriented programming to a greater or lesser degree, typically as part of multiple paradigms in combination with others such as imperative programming and declarative programming. Significant object-oriented languages include Ada, ActionScript, C++, Common Lisp, C#, Dart, Eiffel, Fortran 2003, Haxe, Java, JavaScript, Kotlin, Logo, MATLAB, Objective-C, Object Pascal, Perl, PHP, Python, R, Raku, Ruby, Scala, SIMSCRIPT, Simula, Smalltalk, Swift, Vala and Visual Basic.NET. History The idea of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyboard Shortcut
In computing, a keyboard shortcut (also hotkey/hot key or key binding) is a software-based assignment of an action to one or more keys on a computer keyboard. Most Operating system, operating systems and Application software, applications come with a Table of keyboard shortcuts, default set of keyboard shortcuts, some of which may be modified by the User (computing), user in the Settings (Windows), settings. Keyboard configuration software allows users to create and assign Macro (computer science), macros to key combinations which can perform more complex sequences of actions. Some older keyboards had a physical macro key specifically for this purpose. Terminology The precise words used for these assignments and their meaning can vary depending on the context. For example, Microsoft has generally used ''keyboard shortcuts'' for Microsoft Windows, Windows and Microsoft Office since the transition to 64-bit computing, 64-bit for Windows 7. However, they used ''hot keys'' pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java
Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, projected to rise to 158 million at mid 2025, Java is the world's List of islands by population, most populous island, home to approximately 55.7% of the Demographics of Indonesia, Indonesian population (only approximately 44.3% of Indonesian population live outside Java). Indonesia's capital city, Jakarta, is on Java's northwestern coast. Many of the best known events in Indonesian history took place on Java. It was the centre of powerful Hindu-Buddhist empires, the Islamic sultanates, and the core of the colonial Dutch East Indies. Java was also the center of the History of Indonesia, Indonesian struggle for independence during the 1930s and 1940s. Java dominates Indonesia politically, economically and culturally. Four of Indonesia's eig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gang Of Four (software)
''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 Ric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synonyms
A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all synonyms of one another: they are ''synonymous''. The standard test for synonymy is substitution: one form can be replaced by another in a sentence without changing its meaning. Words may often be synonymous in only one particular sense: for example, ''long'' and ''extended'' in the context ''long time'' or ''extended time'' are synonymous, but ''long'' cannot be used in the phrase ''extended family''. Synonyms with exactly the same meaning share a seme or denotational sememe, whereas those with inexactly similar meanings share a broader denotational or connotational sememe and thus overlap within a semantic field. The former are sometimes called cognitive synonyms and the latter, near-synonyms, plesionyms or poecilonyms. Lexic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambiguity
Ambiguity is the type of meaning (linguistics), meaning in which a phrase, statement, or resolution is not explicitly defined, making for several interpretations; others describe it as a concept or statement that has no real reference. A common aspect of ambiguity is uncertainty. It is thus an Attribute grammar, attribute of any idea or statement whose intention, intended meaning cannot be definitively resolved, according to a rule or process with a finite number of steps. (The prefix ''wikt:ambi-#Prefix, ambi-'' reflects the idea of "2 (number), two", as in "two meanings"). The concept of ambiguity is generally contrasted with vagueness. In ambiguity, specific and distinct interpretations are permitted (although some may not be immediately obvious), whereas with vague information it is difficult to form any interpretation at the desired level of specificity. Linguistic forms Lexical ambiguity is contrasted with semantic ambiguity. The former represents a choice between a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wizard (software)
A software wizard or setup assistant or multi-step form is a user interface that leads a user through a sequence of small steps, such as a dialog box to configure a program for the first time. They are used to make complex, unfamiliar tasks easier by breaking them into smaller pieces. History Before the 1990s, "wizard" was a common term for a technical expert, comparable to "hacker." The 1985 textbook Structure and Interpretation of Computer Programs was nicknamed the "Wizard Book" for the illustration on its cover; its first chapter says, "A computational process is indeed much like a sorcerer's idea of a spirit." When developing the first version of its desktop publishing software, Microsoft Publisher, around 1991, Microsoft wanted to help users create well-presented documents in spite of their lack of graphic design skills. Microsoft reasoned that, no matter the tools a program offered, users would not know how best to use them. Publisher's "Page Wizards" instead provided a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Engine
A database engine (or storage engine) is the underlying software component that a database management system (DBMS) uses to create, read, update and delete (CRUD) data from a database. Most database management systems include their own application programming interface (API) that allows the user to interact with their underlying engine without going through the user interface of the DBMS. The term "database engine" is frequently used interchangeably with " database server" or "database management system". A "database instance" refers to the processes and memory structures of the running database engine. Storage engines Many of the modern DBMS support multiple storage engines within the same database. For example, MySQL supports InnoDB as well as MyISAM. Some storage engines are transactional. Additional engine types include: * Embedded database engines * In-memory database engines Design considerations Information in a database is stored in the form of bits, laid out in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Transaction
A database transaction symbolizes a unit of work, performed within a database management system (or similar system) against a database, that is treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes: # To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure. For example: when execution prematurely and unexpectedly stops (completely or partially) in which case many operations upon a database remain uncompleted, with unclear status. # To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the programs' outcomes are possibly erroneous. In a database management system, a transaction is a single unit of logic or work, sometimes made up of multiple operations. Any logical calculation done in a consistent mode in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread Pool
In computer programming, a thread pool is a software design pattern for achieving concurrency of execution in a computer program. Often also called a replicated workers or worker-crew model, a thread pool maintains multiple threads waiting for tasks to be allocated for concurrent execution by the supervising program. By maintaining a pool of threads, the model increases performance and avoids latency in execution due to frequent creation and destruction of threads for short-lived tasks. Another good property - the ability to limit system load, when we use fewer threads than available. The number of available threads is tuned to the computing resources available to the program, such as a parallel task queue after completion of execution. Performance The size of a thread pool is the number of threads kept in reserve for executing tasks. It is usually a tunable parameter of the application, adjusted to optimize program performance. Deciding the optimal thread pool size is crucia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Progress Bar
A progress bar is a graphical control element used to visualize the progression of an extended computer operation, such as a download, file transfer, or installation. Sometimes, the graphic is accompanied by a textual representation of the progress in a percent format. The concept can also be regarded to include "playback bars" in Media player (software), media players that keep track of the current location in the duration of a media file. A more recent development is the , which is used in situations where the extent of the task is unknown or the progress of the task cannot be determined in a way that could be expressed as a percentage. This bar uses motion or some other indicator (such as a barber's pole pattern) to show that progress is taking place, rather than using the size of the filled portion to show the total amount of progress, making it more like a throbber than a progress bar. There are also indeterminate progress indicators, which are not bar shaped. History Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undo
Undo is an interaction technique which is implemented in many computer programs. It erases the last change done to the document, reverting it to an older state. In some more advanced programs, such as graphic processing, undo will negate the last command done to the file being edited. With the possibility of undo, users can explore and work without fear of making mistakes, because they can easily be undone. The expectations for undo are easy to understand: to have a predictable functionality, and to include all "undoable" commands. Usually undo is available until the user undoes all executed operations. But there are some actions which are not stored in the undo list, and thus they cannot be undone. For example, ''save file'' is not undoable, but is queued in the list to show that it was executed. Another action which is usually not stored, and thus not undoable, is ''scrolling'' or ''selection''. The opposite of to undo is to redo. The redo command reverses the undo or advances ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
