How to find out which feature contains a needed plug-in on an Eclipse download site

问题

When developing an RCP application against a target platform, I (and others) often come across dependencies which need to be added from the Eclipse releases software site. Whenever a plug-in is included in my IDE, but not in my target platform, and I try to run the application from the product definition I get a warning screen, informing me that such and such bundle cannot be resolved.

"No problem, just add the feature containing the plug-in from the Eclipse download site to the target platform, and add the needed plug-in to the Plug-in Project / Feature Project, whathaveyou...."

But, AFAIK, there is no simple way (e.g., website) to find out which feature includes which plug-in. E.g., in order to add org.eclipse.ui.views.properties.tabbed, I would need to know that this plug-in is included in the Eclipse Platform SDK feature (amongst others).

Up to now I haven't found an easy way to find out which feature contains which plug-in. I usually start out with googling the plug-in name, and try to find a tutorial or similar among the search results, which might tell me which feature to include in order to get to the plug-in. This can be tedious, of course.

So my question is: Is there a better, perhaps even official (or officious) way to find this information quick and simple?

回答1:

If you fire up the p2 console, you can use the p2 query language to find all features that depend on a bundle. My example is in Eclipse Juno (4.2):

switch to the OSGi console in the console view
ss p2.console # to find the console bundle number
felix:start -t consoleBundleNumber

Now you can issue p2 queries. To find which features in your current install contain org.eclipse.jface, you can use:

osgi> provlpquery this "select(parent | parent.properties['org.eclipse.equinox.p2.type.group'] == true && parent.requirements.exists(rc | everything.exists(iu | iu.id == 'org.eclipse.jface' && iu ~= rc)))" true
org.eclipse.e4.rcp.feature.group 1.1.0.v20120521-2329-8yFTIGF3GGduEYqkQB9M3DKn
org.eclipse.e4.tools.css.spy.feature.feature.group 0.12.0.v20111206-1509-17B-7w3123161302752

To find out which feature includes org.eclipse.ui.views.properties.tabbed you can use:

osgi> provlquery http://download.eclipse.org/releases/juno "select(parent | parent.properties['org.eclipse.equinox.p2.type.group'] == true && parent.requirements.exists(rc | everything.exists(iu | iu.id == 'org.eclipse.ui.views.properties.tabbed' && iu ~= rc)))" true
org.eclipse.amp.amf.feature.group 0.9.0.v20120528-0244
org.eclipse.bpel.feature.feature.group 1.0.1.v20120606-0845-CI
org.eclipse.jwt.feature.feature.group 1.2.0.v201205310546-7O7i-FK_Qj4QkVn3kW9q
org.eclipse.platform.feature.group 4.2.0.v20120528-1648-9JF7BHV8FyMteji0MoOeOuU6sAnxIeYtKNM1dK
org.eclipse.ptp.etfw.tau.feature.group 6.0.0.201206052145
org.eclipse.tcf.te.feature.feature.group 1.0.0.201206051725
org.eclipse.tcf.te.tcf.feature.feature.group 1.0.0.201206051725

In this case, org.eclipse.platform.feature.group is the most correct one.

The first example is querying profiles in the running eclipse, so it uses provlpquery this. The second example is specifying an external p2 repository, so it uses provlquery repo.

See http://wiki.eclipse.org/Equinox_p2_Console_Users_Guide for more information on the p2 console. There's a lot of black magic going on :-)

回答2:

There is also a GUI utility that can answer this question, p2browser:

Add a relevant P2 repository
Filter by IU, capability or (Java) package
Right-click on relevant IU and choose "Open including features"

The utility is also useful for searching for plugins/bundles that provide specific Java package.

回答3:

Although developing quite a few RCP applications, I've not came across a convenient solution for this problem. A good source of plug-ins is the Eclipse IDE itself. To find out the dependencies I find the Dependency Analysis feature in the Plug-in Manifest Editor quite helpful. Moreover one can validate a product configuration via the Validate... button in the to right corner of the Product Configuration Editor. If plug-ins are missing they are listed as a result.

One possiblity I've not tried so far is to define a target platform by specifying one or more software sites instead of relying on locally downloaded features and plug-ins.

Surely this is not the answer you were looking for but imho there's no real solution for this problem. There are just tools and vehicles (partly described above) which help to ease the pain when constructing the target platform of a RCP application.