Creating lanuchers in unity

Most of the postings I have seen on creating launchers in unity refer to the old way of making desktop launchers in previous versions of the gnome-shell.  In unity it is a little bit different.  For example say I want to add a launcher for my installation of Leksah, a nice Haskell IDE.   All I have to do is add a file to my applications directory in

/usr/share/applications

for this one I will call it leksah.desktop as the naming conventions for launchers specifies the .desktop convention

sudo touch /usr/share/applications/leksah.desktop

Now I just need to fill in the .desktop file with the following

[Desktop Entry]
Version=0.10.0.4
Name=Leksah
GenericName=Haskell IDE
Comment=Develop Haskell Software
MimeType=text/x-haskell;text/x-literate-haskell
Exec=/usr/bin/leksah
TryExec=leksah
Icon=/usr/share/leksah/pics/leksah.png
Type=Application
Terminal=false
Categories=Development;

and presto now when I pull up dash and begin to type in Leksah I see my new launcher.

I can also keep this in my favorites on the launcher panel as well.

Getting going with Equinox OSGi and Eclipse Juno

I started to get my feet wet today with Eclipse Equinox and OSGi.  I started with the example Toast application from the OSGi and Equinox book by McAffer.  I followed the instructions step by step for creating the example application with the exception that I am using the Juno integration build of Eclipse along with the latest org.eclipse.osgi and org.eclipse.equinox.* bundles.  Everything went quite smoothly until I reached the point of adding an activator to one of my bundles as an entry point.  The bundle started up and ran until the point at which the following exception showed up in the console:


Launching
Emergency occured at lat=3776999 lon=-12244694 heading=90 speed=50
!SESSION 2012-01-08 20:25:14.148 -----------------------------------------------
eclipse.buildId=unknown
java.version=1.6.0_23
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=en_US
Command-line arguments:  -dev file:/home/ryan/workspace/.metadata/.plugins/org.eclipse.pde.core/Toast/dev.properties -os linux -ws gtk -arch x86_64 -consoleLog -console


!ENTRY org.eclipse.osgi 4 0 2012-01-08 20:25:14.940
!MESSAGE Could not find bundle: org.eclipse.equinox.console
!STACK 0
org.osgi.framework.BundleException: Could not find bundle: org.eclipse.equinox.console
at org.eclipse.osgi.framework.internal.core.ConsoleManager.checkForConsoleBundle(ConsoleManager.java:211)
at org.eclipse.core.runtime.adaptor.EclipseStarter.startup(EclipseStarter.java:296)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:175)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:624)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:579)
at org.eclipse.equinox.launcher.Main.run(Main.java:1433)
at org.eclipse.equinox.launcher.Main.main(Main.java:1409)

When I tried switching back to the version of the org.eclipse.osgi package that came with Indigo all was well, but that was not the goal, I wanted to be up an running with the Juno bundles.  I realized that I needed to add the org.eclipse.equinox.console bundle, but this was a bit elusive at first.  Adding the packages exported by the org.eclipse.equinox.console bundle to my bundle's imported packages does nothing to fix the problem, and neither does adding the bundle itself to my bundle's required plugins.  I found this out by actually debugging the Equinox runtime to find that even when these packages or bundles are added as dependencies they are not loaded into the runtime.  The required changes must take place in the run configuration, or what effectively amounts to command line arguments to org.eclipse.osgi_3.8.0xxx.jar. So I added the org.eclipse.equinox.console bundle to my run configuration targets, got a few more complaints about missing bundles and ultimately wound up also adding org.apache.felix.gogo.shell and org.apache.felix.gogo.runtime.

What this does behind the scenes is creates the following config.ini file that is used in conjunction with the -configuration flag for the org.eclipse.osgi_3.8.0xxx.jar.

#Configuration File

#Sun Jan 08 20:50:34 PST 2012

osgi.bundles=reference\:file\:/home/ryan/workspace/org.equinoxosgi.toast.client.emergency@start,reference\:file\:/home/ryan/workspace/org.equinoxosgi.toast.dev.airbag@start,reference\:file\:/home/ryan/eclipse/juno/eclipse/plugins/org.eclipse.equinox.console_1.0.0.v20111215-1210.jar@start,reference\:file\:/home/ryan/eclipse/juno/eclipse/plugins/org.apache.felix.gogo.shell_0.8.0.v201110170705.jar@start,reference\:file\:/home/ryan/eclipse/juno/eclipse/plugins/org.apache.felix.gogo.runtime_0.8.0.v201108120515.jar@start,reference\:file\:/home/ryan/workspace/org.equinoxosgi.toast.dev.gps@start

osgi.bundles.defaultStartLevel=4

osgi.install.area=file\:/home/ryan/eclipse/juno/eclipse

osgi.framework=file\:/home/ryan/eclipse/juno/eclipse/plugins/org.eclipse.osgi_3.8.0.v20111210-1354.jar

osgi.configuration.cascaded=false

Which tells the osgi runtime to load the required components for console interaction.  I found this out by using the getprop command from the osgi> prompt.

With this out of the way we are now running happily

I hope that this helps someone trying to build an Equinox application in Juno. I have also tested this with openjdk-7 and all is well.