Google Web Toolkit
From Wikipedia, the free encyclopedia
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| Original author(s) | |
|---|---|
| Initial release | May 16, 2006 |
| Stable release | 1.7.0 / 2009-07-13 |
| Written in | Java |
| Operating system | GNU/Linux, Windows, Mac OS X |
| Available in | Java |
| Type | Ajax framework |
| License | Apache License 2.0 |
| Website | http://code.google.com/webtoolkit |
Google Web Toolkit (GWT) (ɡwɪt) is an open source Java software development framework that allows web developers to create and maintain complex JavaScript front-end applications in Java. Other than a few native libraries, everything is Java source that can be built on any supported platform with the included GWT Ant build files. It is licensed under the Apache License version 2.0.[1]
GWT emphasizes reusable, efficient solutions to recurring Ajax challenges, namely asynchronous remote procedure calls, history management, bookmarking, and cross-browser portability.
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[edit] History
GWT version 1.0 RC 1 (build 1.0.20) was released on May 16, 2006.[2] Google announced GWT at the JavaOne conference, 2006.[3]
Release history:
- GWT 1.0 May 17, 2006
- GWT 1.1 August 11, 2006
- GWT 1.2 November 16, 2006
- GWT 1.3 February 5, 2007
- GWT 1.4 August 28, 2007
- GWT 1.5 August 27, 2008
- GWT 1.6 April 07, 2009
- GWT 1.7 July 13, 2009
[edit] Development
Using GWT, developers can rapidly develop and debug AJAX applications in the Java language using the Java development tools of their choice. When the application is deployed, the GWT cross-compiler translates the Java application to standalone JavaScript files that are optionally obfuscated and deeply optimized.
GWT does not revolve only around user interface programming; it is a general set of tools for building any sort of high-performance client-side JavaScript functionality. In live presentations, the developers of GWT emphasize that "GWT is not its libraries" and that it only includes a library but is not fundamentally yet another AJAX library. This open-ended philosophy sometimes surprises developers new to GWT who expect it to provide an end-to-end "on rails" application framework. Indeed, many key architectural decisions are left completely to the developer. The GWT mission statement clarifies the philosophical breakdown of GWT's role versus the developer's role. History is an example of such: although GWT manages history tokens as users click Back or Forward in the browser, it does not prescribe how to map history tokens to an application state.
GWT applications can be run in two modes:
- Hosted mode: The application is run as Java bytecode within the Java Virtual Machine (JVM). This mode is typically used for development, supporting hot swapping of code and debugging.
- Web mode: The application is run as pure JavaScript and HTML, compiled from the Java source. This mode is typically used for deployment.
A command-line utility shipped with GWT, applicationCreator, automatically generates all the files needed to start a GWT project. It can also generate Eclipse project files. Several open-source plugins are available for making GWT development easier with other IDEs. E.g., GWT4NB for NetBeans, Cypal Studio for GWT, Eclipse and JDeveloper etc.
[edit] Components
The major GWT components include:
- GWT Java-to-JavaScript Compiler
- Translates the Java programming language to the JavaScript programming language.
- GWT Hosted Web Browser
- Allows the developers to run and execute GWT applications in hosted mode (the app runs as Java in the JVM without compiling to JavaScript). It is commonly used for debug purpose.
- JRE emulation library
- JavaScript implementations of the commonly used classes in the Java standard class library (such as most of the java.lang package classes and a subset of the java.util package classes).
- GWT Web UI class library
- A set of custom interfaces and classes for creating widgets.
[edit] Features
- Dynamic and reusable UI components: programmers can use pre-designed classes to implement otherwise time-consuming dynamic behaviors, such as drag-and-drop or sophisticated visual tree structures.[4]
- Simple RPC mechanism
- Browser history management
- Support for full-featured Java debugging[3]
- GWT handles all cross-browser issues for the developer.[3]
- JUnit integration
- Easy internationalization
- The developers can mix handwritten JavaScript in the Java source code using the JavaScript Native Interface (JSNI).
- Support for using Google APIs in GWT applications (initially, support for Google Gears)
- Open-source
- The developers can design and develop their application in a pure object-oriented fashion, since they're using Java (instead of JavaScript).[4] Common JavaScript errors, such as typos and type mismatches, are caught at compile time.
- The JavaScript that the GWT compiler generates can be tailored to be either unobfuscated and easy to understand or obfuscated and smaller to download.[4]
- A number of libraries are available for GWT, by Google and third parties. These extend GWTs features.[4]
[edit] Available widgets
As of version 1.4 (August 2007), GWT offers several widgets:[5]
- HTML primitives (Button, Radio Button, Checkbox, TextBox, PasswordTextBox, TextArea, Hyperlink, ListBox, Table etc.)
- PushButton, ToggleButton
- MenuBar
- Tree
- TabBar
- DialogBox
- Panels (PopupPanel, StackPanel, HorizontalPanel, VerticalPanel, FlowPanel, VerticalSplitPanel, HorizontalSplitPanel, DockPanel, TabPanel, DisclosurePanel)
- RichTextArea
- SuggestBox (auto-complete)
The Google Web Toolkit Incubator has additional widgets undergoing development (and likely to be released in future versions of GWT).
Many common widgets not found in the GWT have been implemented in third-party libraries, such as Ext GWT, GWT Component Library, GWT-Ext, GWT Widget Library, GWTiger, Rocket GWT, Dojo, SmartGWT etc.
[edit] Additional frameworks (third-party)
- GWTEventService - remote event listening for GWT
[edit] See also
- Google Code
- Vaadin, a similar framework, which is based on GWT
- Comparison of JavaScript frameworks
- Comparison of web application frameworks
- List of web application frameworks
- Pyjamas (software) Pyjamas, a port of GWT to Python
- RubyJS, a port of GWT to Ruby
- Microsoft Live Labs Volta, a similar approach from Microsoft
- UltraLightClient, a Java based approach for Rich Internet Applications
[edit] References
- ^ "Google Web Toolkit License Information". Google. February 23, 2007. http://code.google.com/webtoolkit/terms.html. Retrieved on 2007-09-25.
- ^ "Google Web Toolkit Release Archive". Google. http://code.google.com/webtoolkit/versions.html. Retrieved on 2007-09-25.
- ^ a b c Olson, Steven Douglas (2007). Ajax on Java. O'Reilly. p. 183. ISBN 978-0596101879.
- ^ a b c d Perry, Bruce W (2007). Google Web Toolkit for Ajax. O'Reilly Short Cuts. O'Reilly. pp. 1–5. ISBN 978-0596510220.
- ^ "Widgets Gallery". Google. http://code.google.com/webtoolkit/documentation/com.google.gwt.doc.DeveloperGuide.UserInterface.WidgetGallery.html. Retrieved on 2007-09-25.
[edit] Bibliography
- Dewsbury, Ryan (December 15, 2007). Google Web Toolkit Applications. Prentice Hall. pp. 608. ISBN 978-0321501967. http://www.informit.com/store/product.aspx?isbn=0321501969.
- Chaganti, Prabhakar (February 15, 2007). Google Web Toolkit: GWT Java Ajax Programming. Packt Publishing. pp. 248. ISBN 978-1847191007. http://www.packtpub.com/google-web-toolkit-GWT-Java-AJAX/book.
- Geary, David (November 17, 2007). Google Web Toolkit Solutions: More Cool & Useful Stuff. Prentice Hall. pp. 408. ISBN 978-0132344814. http://www.informit.com/store/product.aspx?isbn=0132344815.
- Hanson, Robert; Adam Tacy (June 5, 2007). GWT in Action: Easy Ajax with the Google Web Toolkit. Manning. pp. 632. ISBN 978-1933988238. http://www.manning.com/hanson/.
- Cooper, Robert; Charlie Collins (May 12, 2008). GWT in Practice. Manning. pp. 376. ISBN 978-1933988290. http://www.manning.com/cooper/.
[edit] External links
- GWT homepage on Google code
- Official GWT blog
- Official GWT forums
- Google Web Toolkit Incubator
- Conference on GWT organized by Addison-Wesley, Prentice Hall and Pearson Education
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