This document discusses how to conditionally show, hide, enable, and disable commands in Eclipse menus and context menus. It explains that the activeWhen clause is used to show or hide commands, while the enabledWhen clause is used to grey out or enable commands. A command is enabled if at least one handler is active and enabled. It provides an example of using the enabledWhen clause in a plugin.xml extension to only enable a command when a specific part is active.

1. activeWhen, enabledWhen
1. Workbench core expression
2. Expression Definitions
http://help.eclipse.org/luna/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Fguide
%2Fworkbench_cmd_expressions.html
3. Difference :
To show / hide commands from menus, play with the activeWhen clause
To grey / ungrey commands from menu, play with the enabledWhen clause
A command is enabled when at least 1 handler is active and enabled
4. Add extension : plugin.xml > Extensions
<extension point="org.eclipse.ui.handlers">
<handler class="filebrowser.AboutHandler"
commandId="FileBrowser.command.About">
<enabledWhen>
<with variable="activePart">
<instanceof value="filebrowser.BrowserView">
</instanceof>
</with>
</enabledWhen>
</handler>
</extension>
07.15 학습내용

2. Context Menu
1. Add extension : pluin.xml > Extensions
Org.eclipse.ui.menu : context 메뉴를 사용할 클래스의 ID를 LocationURL에 입력
Ex) popup:FileBrowser.browserView
해당 extentsion에 메뉴에 들어갈 command 추가
2. 해당 클래스에 menuManget와 menu생성
MenuManager menuManager = new MenuManager();
Menu menu = menuManager.createContextMenu(Control parent);
parent.setMenu(menu);
getSite().registerContextMenu(menuManager, ISelectionProvider);