Marker Interface
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Marker Interface
The marker interface pattern is a design pattern in computer science, used with languages that provide run-time type information about objects. It provides a means to associate metadata with a class where the language does not have explicit support for such metadata. To use this pattern, a class implements a marker interface (also called tagging interface) which is an empty interface, and methods that interact with instances of that class test for the existence of the interface. Whereas a typical interface specifies functionality (in the form of method declarations) that an implementing class must support, a marker interface need not do so. The mere presence of such an interface indicates specific behavior on the part of the implementing class. Hybrid interfaces, which both act as markers and specify required methods, are possible but may prove confusing if improperly used. Example An example of the application of marker interfaces from the Java programming language is the inte ...
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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 ...
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Java Annotation
In the Java computer programming language, an annotation is a form of syntactic metadata that can be added to Java source code. Classes, methods, variables, parameters and Java packages may be annotated. Like Javadoc tags, Java annotations can be read from source files. Unlike Javadoc tags, Java annotations can also be embedded in and read from Java class files generated by the Java compiler. This allows annotations to be retained by the Java virtual machine at run-time and read via reflection. It is possible to create meta-annotations out of the existing ones in Java. History The Java platform has various ''ad-hoc'' annotation mechanisms—for example, the ''transient'' modifier, or the ''@Deprecated'' javadoc tag. The Java Specification Request JSR-175 introduced the general-purpose annotation (also known as ''metadata'') facility to the Java Community Process in 2002; it gained approval in September 2004. Annotations became available in the language itself beginning w ...
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Joshua Bloch
Joshua J. Bloch (born August 28, 1961) is an American software engineer and a technology author, formerly employed at Sun Microsystems and Google. He led the design and implementation of numerous Java platform features, including the Java Collections Framework, the package, and the mechanism."About the Author"
''Effective Java Programming Language Guide''
He is the author of the programming guide ''Effective Java'' (2001), which won the 2001 Jolt Award, and is a co-author of two other Java books, ''Java Puzzlers'' (2005) and ''Java Concurrency In Practice'' (2006). Bloch holds a in



Design Marker
{{Short description, Technique of documenting design choices in source code In software engineering, a design marker is a technique of documenting ''design choices'' in source code using the Marker Interface pattern. Marker interfaces have traditionally been limited to those interfaces intended for explicit, runtime verification (normally via ''instanceof''). A design marker is a marker interface used to document a design choice. In Java programs the design choice is documented in the marker interface's Javadoc documentation. Many choices made at software design time cannot be directly expressed in today's implementation languages like C# and Java. These design choices (known by names like Design Pattern, Design Contract, RefactoringEffective Programming IdiomsBlueprints
etc.) must be implemented via programming and

Plone (software)
Plone is a free and open source content management system (CMS) built on top of the Zope application server. Plone is positioned as an enterprise CMS and is commonly used for intranets and as part of the web presence of large organizations. High-profile public sector users include the U.S. Federal Bureau of Investigation, Brazilian Government, United Nations, City of Bern (Switzerland), New South Wales Government (Australia), and European Environment Agency. Plone's proponents cite its security track record and its accessibility as reasons to choose Plone. Plone has a long tradition of development happening in so-called "sprints", in-person meetings of developers over the course of several days, the first having been held in 2003 and nine taking place in 2014. The largest sprint of the year is the sprint immediately following the annual conference. Certain other sprints are considered ''strategic'' so are funded directly by the Plone Foundation, although very few attendees are s ...
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Zope
Zope is a family of free and open-source web application servers written in Python, and their associated online community. Zope stands for "Z Object Publishing Environment", and was the first system using the now common object publishing methodology for the Web. Zope has been called a Python killer app, an application that helped put Python in the spotlight. Over the last few years, the Zope community has spawned several additional web frameworks with disparate aims and principles, but sharing philosophy, people, and source code. Zope 2 is still the most widespread of these frameworks, largely thanks to the Plone content management system, which runs on Zope 2. BlueBream (earlier called Zope 3) is less widespread but underlies several large sites, including Launchpad. Grok was started as a more programmer-friendly framework, "Zope 3 for cavemen", and in 2009 Pyramid gained popularity in the Zope community as a minimalistic framework based on Zope principles. History The Zope Corpo ...
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Python (programming Language)
Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically-typed and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. It is often described as a "batteries included" language due to its comprehensive standard library. Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language and first released it in 1991 as Python 0.9.0. Python 2.0 was released in 2000 and introduced new features such as list comprehensions, cycle-detecting garbage collection, reference counting, and Unicode support. Python 3.0, released in 2008, was a major revision that is not completely backward-compatible with earlier versions. Python 2 was discontinued with version 2.7.18 in 2020. Python consistently ranks as ...
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Reflection (computer Science)
In computer science, reflective programming or reflection is the ability of a process to examine, introspect, and modify its own structure and behavior. Historical background The earliest computers were programmed in their native assembly languages, which were inherently reflective, as these original architectures could be programmed by defining instructions as data and using self-modifying code. As the bulk of programming moved to higher-level compiled languages such as Algol, Cobol, Fortran, Pascal, and C, this reflective ability largely disappeared until new programming languages with reflection built into their type systems appeared. Brian Cantwell Smith's 1982 doctoral dissertation introduced the notion of computational reflection in procedural programming languages and the notion of the meta-circular interpreter as a component of 3-Lisp. Uses Reflection helps programmers make generic software libraries to display data, process different formats of data, perform seri ...
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Java (software Platform)
Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cross-platform computing environment. Java is used in a wide variety of computing platforms from embedded devices and mobile phones to enterprise servers and supercomputers. Java applets, which are less common than standalone Java applications, were commonly run in secure, sandboxed environments to provide many features of native applications through being embedded in HTML pages. Writing in the Java programming language is the primary way to produce code that will be deployed as byte code in a Java virtual machine (JVM); byte code compilers are also available for other languages, including Ada, JavaScript, Python, and Ruby. In addition, several languages have been designed to run natively on the JVM, including Clojure, Groovy, and Scala. J ...
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Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ...
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NET Framework
The .NET Framework (pronounced as "''dot net"'') is a proprietary software framework developed by Microsoft that runs primarily on Microsoft Windows. It was the predominant implementation of the Common Language Infrastructure (CLI) until being superseded by the cross-platform .NET project. It includes a large class library called Framework Class Library (FCL) and provides language interoperability (each language can use code written in other languages) across several programming languages. Programs written for .NET Framework execute in a software environment (in contrast to a computer hardware, hardware environment) named the Common Language Runtime (CLR). The CLR is an process virtual machine, application virtual machine that provides services such as security, memory management, and exception handling. As such, computer code written using .NET Framework is called "managed code". FCL and CLR together constitute the .NET Framework. FCL provides the user interface, data access, d ...
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Metadata
Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords. * Structural metadata – metadata about containers of data and indicates how compound objects are put together, for example, how pages are ordered to form chapters. It describes the types, versions, relationships, and other characteristics of digital materials. * Administrative metadata – the information to help manage a resource, like resource type, permissions, and when and how it was created. * Reference metadata – the information about the contents and quality of statistical data. * Statistical metadata – also called process data, may describe processes that collect, process, or produce st ...
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