Page History

*
*Note: If you post a link, please provide a short summary.

*

h2. General

* [#Why does this FAQ exist?]

h2. Terminology

* [#When should I create a feature for my plugin?]
* [#When should I build a source feature/plugin?]

h2. IDE

* [#Where can I get more information about the Eclipse Java compiler?]
* [#Why does Eclipse complain about an already running instance?]

h2. Plugin Development


h3. Configuration

* [#What information do MANIFEST.MF and plugin.xml contain?]
* [#How do I create a plugin project that uses an existing SEAL plugin?]
* [#How do I add a third-party library to SEAL?]

h3. Coding

* [#How can I launch the Eclipse web browser from my plugin?]
* [#How can my view save data via Eclipse main menu (FILE => Save or Save As...)?]
* [#How can I notify Eclipse about the change of "dirty"-ness of my WorkbenchPart?]
* [#What happens when a view is closed?]
* [#How do I access a file in the plugin programmatically?]
* [#How can I manipulate the main workbench menu at runtime?]

h3. Build process

* [#In build.properties, I specified to build a JAR file from my plugin sources. When I deploy my plugin, a class can not be found. What am I doing wrong?]
* [#How do I generate Javadoc with links to APIs on the web?]
* [#Should I deploy my pure Java plugin as a JAR file or as a directory?]

h2. SWT

* [#How can I change the background/foreground color of a button?]
* [#What are the SWT threading issues?]
* [#How do I create a scrollable widget?]

h2. Misc. & Fun

* [#What are the Eclipse runtime options?]
* [#Some Eclipse plugins are JAR files, others are sub-directories. What's the difference?]
* [#How does Eclipse generate the ANT build script (aka build.xml)?]
* [#Where can I find a copy of the OSGi specification?]

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h2. General

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h4. Why does this FAQ exist?

_Answered by Sergei Chevtsov, 06-14-2007_

There are three reasons for why this FAQ exists:

1)  It contains SEAL-specific information.

2) While it is true that you can find all answers about Eclipse on the internet, we found out that they are usually phrased in a very general way and require (too) much time to grasp.

3) Many Eclipse-related questions yield various answers of seemingly unrelated nature. In this FAQ, we only want to give proven and tested information.

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h2. Terminology

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h4. When should I create a feature for my plugin?

_Answered by Sergei Chevtsov, 06-08-2007_

If you think that your plug-in is useful on its own, e.g. to the developers of our sister project CSS, you should create a feature for it.

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h4. When should I build a source feature/plugin?

_Link verified by Sergei Chevtsov, 06-11-2007_

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.pde.doc.user/guide/tools/preference_pages/source_code_locations.htm

]

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.pde.doc.user/guide/tasks/pde_source_generation.htm

]

A source feature is useful for delivering source code to a developer via Eclipse infrastructure

.

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h2. IDE

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h4. Where can I get more information about the Eclipse Java compiler?

_Answered by Sergei Chevtsov, 06-08-2007

_

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.jdt.doc.isv/guide/jdt_api_compile.htm

]

Eclipse uses its own Java compiler that is more flexible than Sun's

.

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h4. Why does Eclipse complain about an already running instance?

_Answered by Sergei Chevtsov, 07-12-2007

_

(Let's assume that you actually don't have a running instance of Eclipse)

Sometimes when Eclipse exits, it doesn't delete the _.metadata/.lock_ file in your workspace. If you are sure what you're doing, rm it manually

.

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h2. Plugin Development

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h4. What information do MANIFEST.MF and plugin.xml contain?

_Link verified by Sergei Chevtsov, 06-11-2007

_

[http://www-128.ibm.com/developerworks/opensource/library/os-ecl-osgi/#N10091

]

MANIFEST.MF contains the plugin description.

plugin.xml defines extensions that the plugin contributes (thus, is optional).

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h4. How do I create a plugin project that uses an existing SEAL plugin?

_Answered by Sergei Chevtsov, 06-08-2007

_

1. Setup SEAL target. [http://www.slac.stanford.edu/grp/lcls/controls/docs/physics/seal/sealdev.html#target

]
2. Create a new plugin project in your workspace.

3. Open the MANIFEST.MF file from the META-INF directory.

4. Choose the DEPENDENCIES tab at the bottom of your editor.

5. Click on ADD... in the "Required Plug-ins" section and select the ID of the desired SEAL plug-in.

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h4. How do I add a third-party library to SEAL?

_Answered by Sergei Chevtsov, 06-08-2007

_

1. Check out the project "external" from our CVS.

2. Copy your JAR file and the corresponding ZIP file with source code to the top directory of "external".

3. Add your JAR file to the build path of "external". Don't forget to check its "exported" box\!

4. Attach source from the ZIP file and specify Javadoc location on the web for the library.

5. Open the MANIFEST.MF file from the META-INF directory of "external".

6. Choose the RUNTIME tab at the bottom of your editor.

7. Click on ADD.. in the "Exported Packages" section and select all desired packages.

8. Click on ADD... in the "Classpath" section and select the new JAR file.

9. Commit "external" to CVS

.

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h4. How can I launch the Eclipse web browser from my plugin?

_Link verified by Sergei Chevtsov, 06-08-2007

_

[http://wiki.eclipse.org/index.php?title=How_can_I_invoke_the_eclipse_default_web_browser_in_my_own_plugin?

]

((IWebBrowser)browser).openURL(new URL("http://www.eclipse.org"));

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h4. How can my view save data via Eclipse main menu (FILE => Save or Save As...)?

_Answered by Sergei Chevtsov, 06-13-2007

_

[http://help.eclipse.org/help32/nftopic/org.eclipse.platform.doc.isv/reference/api/org/eclipse/ui/ISaveablePart.html

]

Your view must implement ISaveablePart.

Note #1: An editor already implements ISaveablePart.

Note #2: I am not saying that this always is the correct way to save data from a view.

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h4. How can I notify Eclipse about the change of "dirty"-ness of my WorkbenchPart?

_Answered by Sergei Chevtsov, 07-11-2007

_

0. Make sure that your WorkbenchPart implements ISaveablePart.

1. Call WorkbenchPart.firePropertyChange(ISaveablePart.PROP_DIRTY)

.

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h4. What happens when a view is closed?

_Answered by Sergei Chevtsov, 06-13-2007

_

[http://www.eclipse.org/articles/viewArticle/ViewArticle2.html

]

_When the view is closed the lifecycle is completed.

_
_1. The parent Composite passed to createPartControl is disposed.  This children are also implicitly disposed.  If you wish to run any code at this time, you must hook the control dispose event.

_
_2. The IViewPart.dispose method is called to terminate the part lifecycle.  This is the last method which the workbench will call on the part.  It is an ideal time to release any fonts, images, etc.

_

Note: Although the article is old, this behavior is still valid

.

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h4. How do I access a file in the plugin programmatically?

_Answered by Sergei Chevtsov, 06-14-2007

_

Basically, use _FileLocator_.

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/api/org/eclipse/core/runtime/FileLocator.html

]
Similar methods in other classes are deprecated and call _FileLocator_ anyway.

To get a _Bundle_ instance associated with the desired plugin, use _((Plugin)myPlugin).getBundle()_.

([http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/api/org/eclipse/core/runtime/Plugin.html])

If you can't access the instance of the desired _Plugin_, then (in addition to yelling at the plugin developer

 :-)) use _Platform.getBundle(symbolicName)_ where "symbolicName" is specified in the plugin's MANIFEST.MF file.

([http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/api/org/eclipse/core/runtime/Platform.html])

Finally, use _new Path(myPath)_, where "myPath" is relative to the plugin's top directory, to get an instance of _IPath.

_
([http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/api/org/eclipse/core/runtime/Path.html

])

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h4. How can I manipulate the main workbench menu at runtime?

_Answered by Sergei Chevtsov, 06-14-2007

_

[http://wiki.eclipse.org/index.php/Menu_Contributions

]

Not possible yet, but should be in Eclipse 3.3

.

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h4. In build.properties, I specified to build a JAR file from my plugin sources. When I deploy my plugin, a class can not be found. What am I doing wrong?

_Answered by Sergei Chevtsov, 07-11-2007

_

-You must add your JAR file to "Bundle-Classpath" in MANIFEST.MF.

-
-Open MANIFEST.MF. Select the RUNTIME tab. Press NEW... button in the CLASSPATH section and type the name of your (future) library.

-

As of July 2007, we recommend that your plugin stays free of JAR files. If you have an external jar, put it into "edu.stanford.slac.external" and make that plugin required by your plugin.

----
h4. How do I generate Javadoc with links to APIs on the web?

_Answered by Sergei Chevtsov, 07-20-2007_

1. Use the Export Wizard to generate Javadoc for your classes. Check "Save the settings as an Ant script" on the last page.
2. Open javadoc.xml.
3. For each external API, add the following line as child of _<javadoc>_ element:
{{<link href="_url to the API directory on the web_"      />}}

Some of the most common URLs are:
JDK => [http://java.sun.com/j2se/1.5.0/docs/api/

]
Eclipse => [http://help.eclipse.org/help32/nftopic/org.eclipse.platform.doc.isv/reference/api/

]
SEAL plugin => [http://www.slac.stanford.edu/grp/lcls/controls/docs/seal/{PLUGIN NAME}/javadoc/

]

4. Right click javadoc.xml => "Run As" => "Ant Build".

5. Don't *ever* use the Export Wizard to generate Javadoc again.

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h4. Should I deploy my pure Java plugin as a JAR file or as a directory?

_Answered by Sergei Chevtsov, 07-11-2007

_

First, you need to know that your plugin will \*run\* either way, although Eclipse folks claim that performance might differ (surprisingly, JAR-ed plugins are supposed to be better =>

[http://www.eclipsezone.com/eclipse/forums/m91980917.html#91980917]).

If that's all your plugin is intended for, the choice seems to be entirely up to you.

However, some plugins can be used by other plugins; such plugins expose packages to the clients. You must create a JAR file for a plugin that exposes packages, so that Eclipse's Plug-in Development Environment can locate the exported classes.

Note: if your plugin uses an external library, put it into edu.stanford.slac.external plugin and make that plugin required by your plugin

.

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h2. SWT

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h4. How can I change the background/foreground color of a button?

_Answered by Sergei Chevtsov, 06-08-2007

_

Surprisingly, you can't.

----
h4. What are the SWT threading issues?

_Answered by Sergei Chevtsov, 06-13-2007

_

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/guide/swt_threading.htm

]

You can only access SWT widgets from a UI thread.

----
h4. How do I create a scrollable widget?

_Answered by Sergei Chevtsov, 06-14-2007

_

Try specifying the following style bits in the constructor of your widget: SWT.H_SCROLL and/or SWT.V_SCROLL.

If it doesn't work, then you could use the _ScrolledComposite_ class, e.g. =>

[http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet5.java?view=co

]

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h2. Misc. & Fun

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h4. What are the Eclipse runtime options?

_Link verified by Sergei Chevtsov, 07-11-2007

_

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.platform.doc.isv/reference/misc/runtime-options.html

]

Some of the most useful options are: clean, console, debug (note: it actually enables tracing only), nl, noSplash, password, vm, vmArgs.

----
h4. How does Eclipse generate the ANT build script (aka build.xml)?

_Link verified by Sergei Chevtsov, 06-11-2007

_

[http://help.eclipse.org/help32/index.jsp?topic=/org.eclipse.pde.doc.user/guide/tasks/pde_feature_generating_ant.htm

]

It uses build.properties from your plugin's top directory

.

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h4. Where can I find a copy of the OSGi specification?

_Answered by Sergei Chevtsov, 06-11-2007

_

Since you have to register to download it from [http://www2.osgi.org/Specifications/HomePage], here is a local copy:

 [^r4.core.pdf

]

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