Nexaweb Studio是一个基于Eclipse的可视化RIA开发平台，昨天发布了4.0版本。
下载地址： www.nexaweb.com/go/eval
以下是该版本的Release Note:

Overview

Building on the improvements in Studio 3.5, Studio 4.0 extends and improves both the utility and usability of several key workflows including events, data binding, and data services. The following are areas of major change. Known issues and resolved defects are also discussed at the end.

1. Simpler Welcome Page
2. New Update Site
3. Tabbed Properties View
4. Improved Macro Wizard / Macro Editor
5. XPath Expression Builder
6. Visual Editor Improvements
7. New and Improved Data Workflow Wizards
8. Expanded Data View capabilities
9. Data Services Wizard Improvements
10. XML Editing Improvements including support for CDATA and Comments
11. Platform Driven Features
12. Usability Enhancements
13. Upgraded Components
14. Backward Compatibility: importing Studio 2.4, 3.0, and 3.5 projects into Studio 4.0 is supported  

This release supports Windows XP and Windows 2000.  Nexaweb Studio is based on Eclipse 3.2.1 - which does not support Windows Vista - therefore this release does not support Windows Vista.

Welcome Page Changes 

• "Take a tour" link added that uses local content to walk the user through the features of Nexaweb
• "Browse Samples" content added with instructions and the user is then directed to the Nexaweb Perspective - rather than the Subclipse perspective - to simplify downloading and running samples.
• Documentation links combined

New Update Site

Nexaweb Studio can now be installed into existing Eclipse-based environments via a new update site (http://dev.nexaweb.com/update).  This includes:

• Visual Editor
• Event/Data/DS workflow
• License manager
• Add support (Platform exe and zip from dojoe/xap)
• Open XAL files in any project

For more information see the installation instructions page.

Tabbed Properties View

The properties view has been changed to leverage the tabbed property view to make access of properties faster and more intuitive. 

• Attribute groups now each have a separate tab
• Support for user-defined custom attributes
• Integration with the Data View
• Support for non-ui components (e.g. mco, macro, iterator)
• Performance Improvements
• Improved support of clipboard operations

Macro Wizard and Editor

A rich macro builder has been added that allows creation and management of complex macros, exposing all macro functionality available to the user in a clear and usable fashion.

• Support for multiple modifications in a macro
• New workflow for editing an existing macro
• Support for mco:execute and macro:macroCall commands within a macro
• Integration with the XPath Expression builder

XPath Expression Builder

XPath expressions are an important part of building Nexaweb applications especially Macros and Data

• XPath syntax validation
• Content assist
• document browsing - particularly useful with data workflow
• Integration with Data Workflows
• Integration with Macro Wizard

Visual Editor

Further feature enhancements have been made:

• Support for rubber banding
• More consistent handling of complex components and nested components
• Additional stability and performance fixes
• Double-click now opens the manage-events dialog

Data Workflow

Previous data workflow consisted of single dialog interfaces for configuring the attributes of a data tag.  In Studio 4.0 new workflow has been added that guides the user through common actions and provides clear paths to connect data and user interface together.

New workflow:

• Create data source
• Create data binding
• Populate Component with Iterator
• Create iterator
• Create formatter

Additionally, these workflows have been linked together, and linked to other workflow, so that combined with clear descriptions of each step users should be able to quickly and easily add data to their application.

Data View

To better support the Data workflows, the data view has been improved to bring its utility on par with the Outline View.

• Properties View Integration
• Context Menu support
• Connection management - connected dataSources will stay connected
• Drag & drop support - drag an XML file or a JSON file directly into the Data View DataSources node to launch the data wizard
• Now included in the Nexaweb perspective by default

Event Wizard Workflow

The existing add event workflow has been expanded to include additional operations that were available but not obvious to users.

• System service functions have been exposed in Java and Ajax
• Data objects have been exposed
• Service request objects have been exposed
• Re-use existing functions has been added for both Java and JavaScript
• Construct expressions to use MCOs and Macros defined in other files

Additionally, these are configured on a per Platform basis, allowing extension of the exposed functionality in future platform releases without requiring a new version of Studio.

Data Service Workflow

New workflow provides a wizard approach to building service requests, hooks in with the other data workflow and fixes some existing issues with building service requests in Studio.

• Automatically copy the WSDL in the WEB-INF/WSDL
• More intuitive workflow
• Ability to temporarily map data sources to a result set
• Inclusion of WSDL Analyzer in the perspective
  

XML Editing Improvements

• Upgrade to the latest version of Oxygen
• Support for comments
• Support for CDATA
• Full configuration of Nexaweb Schemas for proper validation
• type-ahead XML editing when using Oxygen

Platform Driven Features

Several features once hard coded into a particular version of the Studio have been moved into the Platform:

• Insert / Replace operations within the outline view and visual editor
• Palette
• System service definitions

Usability Enhancements

Some additional enhancements have also been added based on the usability results:

• Improved Project Creation dialog
• SVN included in the default perspective
• Package view included in the default perspective
• Context Menu clean up in VE and Outline View
• JSON visualization added to the data view

Component Upgrades

For the "all in one" installer the following components have been upgraded:

• WTP 1.5.4 to 1.5.5
• DTP 1.5.0 to 1.5.2
• Subclipse 1.2.3 to 1.2.4
• Oxygen 7.1 to 8.2

Backwards Compatibility

• Importing Projects from Studio 2.4, 3.0, and 3.5 is supported
  

与Eclipse Platform类似，Eclipse GEF通过大量使用设计模式来得到它的灵活性和扩展性。下面总结以下经常碰到的模式的小结。
1. MVC
与其他图形框架类似，GEF使用MVC来消除UI之间的耦合。
（1）Model:可以用任何Java对象来表示,model必须拥有某种notification机制。
（2）Views: Figure/TreeItems, 在典型的GraphicalEditor中，Figure是用于在GraphicalViewer中显示的Draw2D Figure，而TreeItems用于在Outline中的TreeViewer中显示信息。
（3）Controller(EditPart):通常对于每个Figure对应一个EditPart，EditPart用于修改，很多修改任务都是通过EditPolicy来实现的。
2．Command
Command封装了Model的修改，可以通过继承GEF中的抽象类Command，提供可Redo/Undo功能，我们主要是在execute()/redo()/undo()中完成业务功能的实现。
3. Chain of Responsibility
Chain of Responsibility通过将Request传递给多个对象，并给这些对象机会处理请求，从而将请求的发送者和接受者解除耦合。在GEF中，多个EditPolicy可以收到请求，返回Commands，这些Commands以链的方式组织在一起。
4. State
允许Graphical Editor在内部状态发生改变的时候，修改编辑器的行为。对于GEF Editor，用户切换工具可以改变编辑器的状态。例如，对于鼠标按下事件，编辑器在激活选区工具和激活创建工具下的行为是截然不同的。详细请见org.eclipse.gef.Tool接口，AbstractTool定义了几个state，STATE_xxx.
5. Abstract Factory
提供Interface创建一系列相关或相依赖的对象。这个模式在根据模型部件创建编辑部件时被使用。
6. Factory Method
定义了方法创建对象，但是允许子类决定实例化的类。这个模式没有被单独讨论，但是它是创建编辑部件的另一种可选的方法。createChild方法允许你不使用工厂就创建子编辑部件。

用Eclipse开发插件也有一定时间了，这段时间项目不是很紧张，准备整理一下，把一些学习和平时开发的心得记录下来。

Override是norm，而Overroad是Exception
Override是在Runtime时候判断的，而Overload是在Compile-Time时候判断的
对于Constructor，只能Overload，而不能Override
尽量少用Overroad，就算用了也尽量使用不同数目的参数，以免client混淆。