Graphical Editing Framework

Last updated

The Graphical Editing Framework(GEF) is an Eclipse project that provides framework and end-user components related to graphical applications. [1]

Contents

History

GEF was initially developed as part of IBM's etools (com.ibm.etools.gef) and was contributed to Eclipse in 2002 in version 2.0.0, consisting then of two components: Draw2d, a 2D visualization component based on the Standard Widget Toolkit (SWT) and GEF (MVC), a related model-view-controller framework that can be used to realize graphical editors as part of Eclipse Rich Client Platform (RCP) applications. The first release at Eclipse was GEF 2.1.0 in March 2003. The next major version, GEF 3.0.0, was released in June 2004, providing many new features like support for rules and guides. Zest was added as a third project component in 2007 in version 1.0.0 as part of the GEF 3.4.0 release. Since 2004, when GEF 3.0.0 was released, only compatible changes have been applied to the framework's application programming interface (API).

A new major revision of the framework has been developed in parallel to the maintenance of the GEF 3.x components by the project team since 2010. It is a complete redesign that is much more modular, uses JavaFX instead of SWT as underlying rendering framework, and can be used also independently of Eclipse RCP applications. Commonly referred to as GEF4, its components were initially released in version 0.1.0 (with still provisional API) in June 2015 as part of the GEF 3.10.0 (Mars) release. The GEF4 components are to be published in version 1.0.0 as part of the GEF 4.0.0 (Neon) release in June 2016.

GEF 3.x

GEF 3.x provides framework technology to realize graphical editors and views as part of Eclipse Rich Client Platform (RCP) applications. It is internally decomposed into three components:

While graphical applications can be built on top of the GEF 3.x components directly, Draw2d and GEF (MVC) are also used by the Graphical Modeling Framework (GMF), which combines them with the Eclipse Modeling Framework (EMF) to create the code for both the data model and the graphical editor.

Architecture

Editors created with GEF (MVC) consist of the following components:

Design pattern usage

GEF makes heavy use of design patterns. These patterns are often mandatory under GEF and developers are required to understand them.

  • Model-View-Controller is an architectural design pattern which divides an application into separate parts which communicate with each other in a specific way. The goal is to separate data model (model), graphical user interface (view) and business logic (controller). GEF uses the MVC pattern extensively.
    • Model: The data model can either be generated using EMF, self-implemented by the user or it may already exist in case of a legacy software.
    • Controller: The EditParts act as controllers. Typically, each model element has its matching EditPart. EditParts may contain other EditParts thereby matching model elements containing other model elements. EditParts also have a reference to the figure which graphically represents the model element. Finally, EditParts evaluate requests and create the appropriate command to edit the underlying model.
    • View: For each element within the model, including connections, a figure has to be implemented using the Draw2d framework. Oftentimes the figure is some geometrical drawing.
  • Factory: Creating models from palette, creating EditParts and creating Figures
  • Observer: Typically a controller (EditPart) listening on Model and View
  • Command: To implement Undo and Redo functions
  • Strategy: EditParts can install and remove EditPolicies dynamically
  • Chain of responsibility: To decide which EditPolicy should handle a Request

Request and response mechanism

Any user action with the editor can generate a request. The nature of the request is understood by the context of invocation. The context is determined by the EditPart the user interacts with and the active tool. The tool can be any selected entry in a tool palette. The request is handed over to the selected EditPart, which in turn returns a Command.

This is achieved using the chain of responsibility mechanism over Editpolicies. The editpolicies determine if they can handle the request, otherwise they pass on to the next editpolicy. The order of declaration of editpolicies determine the order in which the request is passed around. The capable editpolicy creates a command. This command is handed back to the tool which initiated the "Request". Execution of the command causes the model to be modified (Response).

Related Research Articles

Cocoa is Apple's native object-oriented application programming interface (API) for its desktop operating system macOS.

<span class="mw-page-title-main">Eclipse (software)</span> Software development environment

Eclipse is an integrated development environment (IDE) used in computer programming. It contains a base workspace and an extensible plug-in system for customizing the environment. It is the second-most-popular IDE for Java development, and, until 2016, was the most popular. Eclipse is written mostly in Java and its primary use is for developing Java applications, but it may also be used to develop applications in other programming languages via plug-ins, including Ada, ABAP, C, C++, C#, Clojure, COBOL, D, Erlang, Fortran, Groovy, Haskell, JavaScript, Julia, Lasso, Lua, NATURAL, Perl, PHP, Prolog, Python, R, Ruby, Rust, Scala, and Scheme. It can also be used to develop documents with LaTeX and packages for the software Mathematica. Development environments include the Eclipse Java development tools (JDT) for Java and Scala, Eclipse CDT for C/C++, and Eclipse PDT for PHP, among others.

<span class="mw-page-title-main">Swing (Java)</span> Java-based GUI toolkit

Swing is a GUI widget toolkit for Java. It is part of Oracle's Java Foundation Classes (JFC) – an API for providing a graphical user interface (GUI) for Java programs.

<span class="mw-page-title-main">Model–view–controller</span> Software design pattern

Model–view–controller (MVC) is a software design pattern commonly used for developing user interfaces that divides the related program logic into three interconnected elements. These elements are:

<span class="mw-page-title-main">Standard Widget Toolkit</span> Graphical widget toolkit for use with the Java platform

The Standard Widget Toolkit (SWT) is a graphical widget toolkit for use with the Java platform. It was originally developed by Stephen Northover at IBM and is now maintained by the Eclipse Foundation in tandem with the Eclipse IDE. It is an alternative to the Abstract Window Toolkit (AWT) and Swing Java graphical user interface (GUI) toolkits provided by Sun Microsystems as part of the Java Platform, Standard Edition (J2SE).

<span class="mw-page-title-main">Graphviz</span> Software package for graph visualization

Graphviz is a package of open-source tools initiated by AT&T Labs Research for drawing graphs specified in DOT language scripts having the file name extension "gv". It also provides libraries for software applications to use the tools. Graphviz is free software licensed under the Eclipse Public License.

In computing, Oracle Application Development Framework, usually called Oracle ADF, provides a Java framework for building enterprise applications. It provides visual and declarative approaches to Java EE development. It supports rapid application development based on ready-to-use design patterns, metadata-driven and visual tools.

A web framework (WF) or web application framework (WAF) is a software framework that is designed to support the development of web applications including web services, web resources, and web APIs. Web frameworks provide a standard way to build and deploy web applications on the World Wide Web. Web frameworks aim to automate the overhead associated with common activities performed in web development. For example, many web frameworks provide libraries for database access, templating frameworks, and session management, and they often promote code reuse. Although they often target development of dynamic web sites, they are also applicable to static websites.

<span class="mw-page-title-main">JFace</span>

JFace is defined by the Eclipse project as "a UI toolkit that provides helper classes for developing UI features that can be tedious to implement." The Standard Widget Toolkit (SWT) is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.

Generic Eclipse Modeling System (GEMS) is a configurable toolkit for creating domain-specific modeling and program synthesis environments for Eclipse. The project aims to bridge the gap between the communities experienced with visual metamodeling tools like those built around the Eclipse modeling technologies, such as the Eclipse Modeling Framework (EMF) and Graphical Modeling Framework (GMF). GEMS helps developers rapidly create a graphical modeling tool from a visual language description or metamodel without any coding in third-generation languages. Graphical modeling tools created with GEMS automatically support complex capabilities, such as remote updating and querying, template creation, styling with Cascading Style Sheets (CSS), and model linking.

QF-Test from Quality First Software is a cross-platform software tool for automated testing of programs via the graphical user interface. The program is specialized on cross-browser test automation of static and dynamic web-based applications. Version 4.1 added support for MacOS and the Apple Safari and Microsoft Edge browsers via the Selenium WebDriver. RESTful web service testing. From version 5.0, Windows applications can also be tested and modern C++ applications. Version 5.3 added support for the Chrome DevTools protocol, which allows browsers to be controlled using CDP drivers.

<span class="mw-page-title-main">Model–view–presenter</span> Software design pattern

Model–view–presenter (MVP) is a derivation of the model–view–controller (MVC) architectural pattern, and is used mostly for building user interfaces.

Web2py is an open-source web application framework written in the Python programming language. Web2py allows web developers to program dynamic web content using Python. Web2py is designed to help reduce tedious web development tasks, such as developing web forms from scratch, although a web developer may build a form from scratch if required.

Java view technologies and frameworks are web-based software libraries that provide the user interface, or "view-layer", of Java web applications. Such application frameworks are used for defining web pages and handling the HTTP requests (clicks) generated by those web pages. As a sub-category of web frameworks, view-layer frameworks often overlap to varying degrees with web frameworks that provide other functionality for Java web applications.

<span class="mw-page-title-main">Apache Pivot</span> Open-source platform for building applications in Java

Apache Pivot is an open-source platform for building rich web applications in Java or any JVM-compatible language. It is released under the Apache License version 2.0.

<span class="mw-page-title-main">Spring Roo</span> Open-source software tool

Spring Roo is an open-source software tool that uses convention-over-configuration principles to provide rapid application development of Java-based enterprise software. The resulting applications use common Java technologies such as Spring Framework, Java Persistence API, Thymeleaf, Apache Maven and AspectJ. Spring Roo is a member of the Spring portfolio of projects.

<span class="mw-page-title-main">ColdBox Platform</span> Web application framework

ColdBox is a free, open-source, conventions-based, modular web application framework intended for building enterprise applications with ColdFusion (CFML) using a Hierarchical MVC approach.

Mojito is an environment agnostic, Model-View-Controller (MVC) web application framework. It was designed by Ric Allinson.

<span class="mw-page-title-main">Eclipse Sirius</span>

Sirius is an open-source software project of the Eclipse Foundation. This technology allows users to create custom graphical modeling workbenches by leveraging the Eclipse Modeling technologies, including EMF and GMF. The modeling workbench created is composed of a set of Eclipse editors which allow the users to create, edit and visualize EMF models.

References

  1. Web, Eclipse (2013-01-31). "Eclipse Graphical Editing Framework (GEF)". projects.eclipse.org. Retrieved 2024-01-12.