Nexaweb Studio是一個(gè)基于Eclipse的可視化RIA開(kāi)發(fā)平臺(tái)，昨天發(fā)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(guò)大量使用設(shè)計(jì)模式來(lái)得到它的靈活性和擴(kuò)展性。下面總結(jié)以下經(jīng)常碰到的模式的小結(jié)。
1. MVC
與其他圖形框架類似，GEF使用MVC來(lái)消除UI之間的耦合。
（1）Model:可以用任何Java對(duì)象來(lái)表示,model必須擁有某種notification機(jī)制。
（2）Views: Figure/TreeItems, 在典型的GraphicalEditor中，F(xiàn)igure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(duì)于每個(gè)Figure對(duì)應(yīng)一個(gè)EditPart，EditPart用于修改，很多修改任務(wù)都是通過(guò)EditPolicy來(lái)實(shí)現(xiàn)的。
2．Command
Command封裝了Model的修改，可以通過(guò)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(yè)務(wù)功能的實(shí)現(xiàn)。
3. Chain of Responsibility
Chain of Responsibility通過(guò)將Request傳遞給多個(gè)對(duì)象，并給這些對(duì)象機(jī)會(huì)處理請(qǐng)求，從而將請(qǐng)求的發(fā)送者和接受者解除耦合。在GEF中，多個(gè)EditPolicy可以收到請(qǐng)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(nèi)部狀態(tài)發(fā)生改變的時(shí)候，修改編輯器的行為。對(duì)于GEF Editor，用戶切換工具可以改變編輯器的狀態(tài)。例如，對(duì)于鼠標(biāo)按下事件，編輯器在激活選區(qū)工具和激活創(chuàng)建工具下的行為是截然不同的。詳細(xì)請(qǐng)見(jiàn)org.eclipse.gef.Tool接口，AbstractTool定義了幾個(gè)state，STATE_xxx.
5. Abstract Factory
提供Interface創(chuàng)建一系列相關(guān)或相依賴的對(duì)象。這個(gè)模式在根據(jù)模型部件創(chuàng)建編輯部件時(shí)被使用。
6. Factory Method
定義了方法創(chuàng)建對(duì)象，但是允許子類決定實(shí)例化的類。這個(gè)模式?jīng)]有被單獨(dú)討論，但是它是創(chuàng)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(chuàng)建子編輯部件。

用Eclipse開(kāi)發(fā)插件也有一定時(shí)間了，這段時(shí)間項(xiàng)目不是很緊張，準(zhǔn)備整理一下，把一些學(xué)習(xí)和平時(shí)開(kāi)發(fā)的心得記錄下來(lái)。

Override是norm，而Overroad是Exception
Override是在Runtime時(shí)候判斷的，而Overload是在Compile-Time時(shí)候判斷的
對(duì)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(shù)目的參數(shù)，以免client混淆。