图形用户界面、程序及并发性(中文4000字,英文2900字)
基本的设计准则是“使简单的事情很容易,困难的事。“最初的设计目标的图形用户界面(GUI)图书馆在Java l。o是允许程序员在所有平台上建立一个看起来不错的GUI。这一目标并未实现。相反,Java l。o抽象窗口工具包(AWT)产生一个GUI,看起来同样平庸的所有系统。此外,这是限制;您可以使用只有四个字体和你不能访问任何更复杂的GUI元素,存在于您的操作系统。Java 1.0 AWT也尴尬的和非面向对象的编程模型。一个学生在我的一个研讨会(曾在SUN公司的创建Java)解释了为什么:原AWT被构想,设计和实现一个月。当然一个奇迹的生产力,也为什么设计是重要的教训。Java 1.1的情况改善AWT事件模型,需要更清晰,面向对象的方法,随着javabean,一个面向组件编程模型简单的可视化编程环境的创建。Java 2(JDK 1.2)完成转换远离旧的Java 1.0 AWT基本上取代一切与Java基础类(JFC)的GUI部分被称为“摇摆。“这些都是一组丰富的易于使用,易于理解的javabean可以拖(以及手程序)来创建一个合理的GUI。软件行业的“修订3”规则(一个产品不好,直到修订3)似乎适用与编程语言。本章介绍现代Java Swing库并做出合理的假设—Swing是SUN公司的最终目的地为Java GUI库。
Graphical User Interfaces&Applets&Concurrency
A fundamental design guideline is "Make simple things easy, and difficult things possible."The original design goal of the graphical user interface (GUI) library in Java l.o was to allow the programmer to build a GUI that looks good on all platforms. That goal was not achieved. Instead, the Java l.o Abstract Windowing Toolkit (AWT) produced a GUI that looked equally mediocre on all systems. In addition, it was restrictive; you could use only four fonts and you couldn’t access any of the more sophisticated GUI elements that exist in your operating system. The Java 1.0 AWT programming model was also awkward and non-object-oriented. A student in one of my seminars (who had been at Sun during the creation of Java) explained why: The original AWT had been conceived, designed, and implemented in a month. Certainly a marvel of productivity, and also an object lesson in why design is important. The situation improved with the Java 1.1 AWT event model, which takes a much clearer, object-oriented approach, along with the addition of JavaBeans, a component programming model that is oriented toward the easy creation of visual programming environments. Java 2 (JDK 1.2) finished the transformation away from the old Java 1.0 AWT by essentially replacing everything with the Java Foundation Classes (JFC), the GUI portion of which is called "Swing." These are a rich set of easy-to-use, easy-to-understand JavaBeans that can be dragged and dropped (as well as hand programmed) to create a reasonable GUI. The "revision 3" rule of the software industry (a product isn’t good until revision 3) seems to hold true with programming languages as well. This chapter introduces the modern Java Swing library and makes the reasonable assumption that Swing is Sun’s final destination GUI library for Java. |
