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Proactor Pattern
Proactor is a software design pattern for event handling in which long running activities are running in an asynchronous part. A ''completion handler'' is called after the asynchronous part has terminated. The proactor pattern can be considered to be an asynchronous variant of the synchronous reactor pattern.Pattern-Oriented Software Architecture, Volume 2, Schmidt et al., Jon Wiley & Sons, Ltd, 2000 Interaction Operation specific actors: * The ''Proactive Initiator'' starts the asynchronous operation via the Asynchronous Operation Processor and defines the Completion Handler * ''Completion Handler'' is a call at the end of the operation from the Asynchronous Operation Processor * ''Asynchronous Operation'' Standardized actors * The ''Asynchronous Operation Processor'' controls the whole asynchronous operation * The ''Completion Dispatcher'' handles the call, depending on the execution environment. Implementations Proactor and Boost.Asio(C++) * Adaptive Communication Environ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Pattern (computer Science)
In software engineering, a software design pattern is a general, reusable solution to a commonly occurring problem within a given context in software design. It is not a finished design that can be transformed directly into source or machine code. Rather, it is a description or template for how to solve a problem that can be used in many different situations. Design patterns are formalized best practices that the programmer can use to solve common problems when designing an 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 not necessarily suitable for non-object-oriented langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Handling
In programming and software design, an event is an action or occurrence recognized by software, often originating asynchronously from the external environment, that may be handled by the software. Computer events can be generated or triggered by the system, by the user, or in other ways. Typically, events are handled synchronously with the program flow; that is, the software may have one or more dedicated places where events are handled, frequently an event loop. A source of events includes the user, who may interact with the software through the computer's peripherals - for example, by typing on the keyboard. Another source is a hardware device such as a timer. Software can also trigger its own set of events into the event loop, e.g. to communicate the completion of a task. Software that changes its behavior in response to events is said to be event-driven, often with the goal of being interactive. Description Event driven systems are typically used when there is so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous
Asynchrony is the state of not being in synchronization. Asynchrony or asynchronous may refer to: Electronics and computing * Asynchrony (computer programming), the occurrence of events independent of the main program flow, and ways to deal with such events ** Async/await * Asynchronous system, a system having no global clock, instead operating under distributed control ** Asynchronous circuit, a sequential digital logic circuit not governed by a clock circuit or signal ** Asynchronous communication, transmission of data without the use of an external clock signal * Asynchronous cellular automaton, a mathematical model of discrete cells which update their state independently * Asynchronous operation, a sequence of operations executed out of time coincidence with any event Other uses * Asynchrony (game theory), when players in games update their strategies at different time intervals * Asynchronous learning, an educational method in which the teacher and student are separated in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronization (computer Science)
In computer science, synchronization refers to one of two distinct but related concepts: synchronization of processes, and synchronization of data. ''Process synchronization'' refers to the idea that multiple processes are to join up or handshake at a certain point, in order to reach an agreement or commit to a certain sequence of action. ''Data synchronization'' refers to the idea of keeping multiple copies of a dataset in coherence with one another, or to maintain data integrity. Process synchronization primitives are commonly used to implement data synchronization. The need for synchronization The need for synchronization does not arise merely in multi-processor systems but for any kind of concurrent processes; even in single processor systems. Mentioned below are some of the main needs for synchronization: '' Forks and Joins:'' When a job arrives at a fork point, it is split into N sub-jobs which are then serviced by n tasks. After being serviced, each sub-job waits until al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactor Pattern
The reactor design pattern is an event handling pattern for handling service requests delivered concurrently to a service handler by one or more inputs. The service handler then demultiplexes the incoming requests and dispatches them synchronously to the associated request handlers. Structure ;Resources: Any resource that can provide input to or consume output from the system. ;Synchronous Event Demultiplexer: Uses an event loop to block on all resources. The demultiplexer sends the resource to the dispatcher when it is possible to start a synchronous operation on a resource without blocking (''Example:'' a synchronous call to read() will block if there is no data to read. The demultiplexer uses select() on the resource, which blocks until the resource is available for reading. In this case, a synchronous call to read() won't block, and the demultiplexer can send the resource to the dispatcher.) ;Dispatcher: Handles registering and unregistering of request handlers. Dispatches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Communication Environment
The Adaptive Communication Environment (ACE) is an open source software framework used for network programming. It provides a set of object-oriented C++ classes designed to help address the inherent complexities and challenges in network programming by preventing common errors. History ACE was initially developed by Douglas C. Schmidt during his graduate work at the University of California, Irvine. Development followed him to the Washington University in St. Louis, where he was employed. ACE is open-source software released by WU's Distributed Object Computer (DOC) group. Its development continued in the Institute for Software Integrated Systems (ISIS) at Vanderbilt University. Features ACE provides a standardized usage for operating system/machine specific features. It provides common data types and methods to access the powerful but complex features of modern operating systems. These include: inter-process communication, thread management, efficient memory management, etc. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactor Pattern
The reactor design pattern is an event handling pattern for handling service requests delivered concurrently to a service handler by one or more inputs. The service handler then demultiplexes the incoming requests and dispatches them synchronously to the associated request handlers. Structure ;Resources: Any resource that can provide input to or consume output from the system. ;Synchronous Event Demultiplexer: Uses an event loop to block on all resources. The demultiplexer sends the resource to the dispatcher when it is possible to start a synchronous operation on a resource without blocking (''Example:'' a synchronous call to read() will block if there is no data to read. The demultiplexer uses select() on the resource, which blocks until the resource is available for reading. In this case, a synchronous call to read() won't block, and the demultiplexer can send the resource to the dispatcher.) ;Dispatcher: Handles registering and unregistering of request handlers. Dispatches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Douglas C
Douglas may refer to: People * Douglas (given name) * Douglas (surname) Animals *Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking *Douglas the camel, a camel in the Confederate Army in the American Civil War Businesses * Douglas Aircraft Company * Douglas (cosmetics), German cosmetics retail chain in Europe * Douglas (motorcycles), British motorcycle manufacturer Peerage and Baronetage * Duke of Douglas * Earl of Douglas, or any holder of the title * Marquess of Douglas, or any holder of the title * Douglas Baronets Peoples * Clan Douglas, a Scottish kindred * Dougla people, West Indians of both African and East Indian heritage Places Australia * Douglas, Queensland, a suburb of Townsville * Douglas, Queensland (Toowoomba Region), a locality * Port Douglas, North Queensland, Australia * Shire of Douglas, in northern Queensland Belize * Douglas, Belize Douglas is a village situated by the Rio Hondo river in Orange Walk Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Events (computing)
Event may refer to: Gatherings of people * Ceremony, an event of ritual significance, performed on a special occasion * Convention (meeting), a gathering of individuals engaged in some common interest * Event management, the organization of events * Festival, an event that celebrates some unique aspect of a community * Happening, a type of artistic performance * Media event, an event created for publicity * Party, a social, recreational or corporate events held * Sporting event, at which athletic competition takes place * Virtual event, a gathering of individuals within a virtual environment Science, technology, and mathematics * Event (computing), a software message indicating that something has happened, such as a keystroke or mouse click * Event (philosophy), an object in time, or an instantiation of a property in an object * Event (probability theory), a set of outcomes to which a probability is assigned * Event (relativity), a point in space at an instant in time, i.e. a lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
