Nexaweb Studio是一個基于Eclipse的可視化RIA開發平臺，昨天發布了4.0版本。
下載地址： www.nexaweb.com/go/eval
以下是該版本的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
  

與Eclipse Platform類似，Eclipse GEF通過大量使用設計模式來得到它的靈活性和擴展性。下面總結以下經常碰到的模式的小結。
1. MVC
與其他圖形框架類似，GEF使用MVC來消除UI之間的耦合。
（1）Model:可以用任何Java對象來表示,model必須擁有某種notification機制。
（2）Views: Figure/TreeItems, 在典型的GraphicalEditor中，Figure是用于在GraphicalViewer中顯示的Draw2D Figure，而TreeItems用于在Outline中的TreeViewer中顯示信息。
（3）Controller(EditPart):通常對于每個Figure對應一個EditPart，EditPart用于修改，很多修改任務都是通過EditPolicy來實現的。
2．Command
Command封裝了Model的修改，可以通過繼承GEF中的抽象類Command，提供可Redo/Undo功能，我們主要是在execute()/redo()/undo()中完成業務功能的實現。
3. Chain of Responsibility
Chain of Responsibility通過將Request傳遞給多個對象，并給這些對象機會處理請求，從而將請求的發送者和接受者解除耦合。在GEF中，多個EditPolicy可以收到請求，返回Commands，這些Commands以鏈的方式組織在一起。
4. State
允許Graphical Editor在內部狀態發生改變的時候，修改編輯器的行為。對于GEF Editor，用戶切換工具可以改變編輯器的狀態。例如，對于鼠標按下事件，編輯器在激活選區工具和激活創建工具下的行為是截然不同的。詳細請見org.eclipse.gef.Tool接口，AbstractTool定義了幾個state，STATE_xxx.
5. Abstract Factory
提供Interface創建一系列相關或相依賴的對象。這個模式在根據模型部件創建編輯部件時被使用。
6. Factory Method
定義了方法創建對象，但是允許子類決定實例化的類。這個模式沒有被單獨討論，但是它是創建編輯部件的另一種可選的方法。createChild方法允許你不使用工廠就創建子編輯部件。

用Eclipse開發插件也有一定時間了，這段時間項目不是很緊張，準備整理一下，把一些學習和平時開發的心得記錄下來。

Override是norm，而Overroad是Exception
Override是在Runtime時候判斷的，而Overload是在Compile-Time時候判斷的
對于Constructor，只能Overload，而不能Override
盡量少用Overroad，就算用了也盡量使用不同數目的參數，以免client混淆。

最近在研究JMX，剛剛瀏覽了JMX in Action，把一些要點記載下來，以供以后查閱。
1、JMX是Sun公司的一個標準。分為三層，分別是：
??????Instrumentation: 最里面的一層，包括MBean
??????Agent: MBean Server
??????Distributed:最外面的一層，包括Connector與Adapter
2、客戶端通過調用Distributed層的API，通過MBean Server查找MBean，然后直接管理MBean。這是我暫時的一點總結。
3、MBean的類型：
????????Standart MBean：最簡單的MBean
????????Dynamic MBean：
????????Model MBean：
????????OpenMBean：
通過Notification可以讓MBean間互相通信。
4、Agent層的四種服務：
??????Management-Applet(M-let)服務：動態MBean加載
??????Relation服務：處理MBean間的關系
??????Monitor服務：
??????Timer服務：