How to specify and read properties in an Eclipse plugin - eclipse

Question

I have an Eclipse product which uses my own plugins. I want to read some properties based on user inputs. I want to persist these properties on some user action, and read those properties back when required. Can this be achieved using some Eclipse API?
A more elaborate description of the above problem:
Say I have a property abc=xyz in a config file myconfig.ini. This property is read by the perspective during the bootstrapping process. During use of the perspective, some action sets this property to a new value xyz=def. Now, I should be able to save the new value in myconfig.ini. So next time the bootstrapping happens, the value of xyz is read as def instead of abc. However, I can also choose to manually set it to abc by editing the myconfig.ini file.
How would I manage myconfig.ini? Where should it exist within my eclipse product project?
What is the best API to manage reading, writing and updating properties in myconfig.ini?

Answer 1

You can use resource markers mechanism:
IMarker marker = file.createMarker(IMarker.MARKER);
marker.setAttribute(IMarker.MESSAGE, "blabla");
marker.setAttribute("attr", 5);
You can search for markers by using the findMarkers methods on IResource.
See FAQ also

Answer 2

You should consider using the apache configurations API http://commons.apache.org/proper/commons-configuration/
It can read and write INI files and if you want to change the configuration file type or add more configuration options you can simply configure it.
I would add a hidden directory to the workspace root e.g. ${WORKSPACE}/.productName/product.ini
and add an ISaveParticipant that ensures the ini file gets updated on shutdown.
You can get the Workspace using the ResourcesPlugin
IWorkspace workspace = ResourcesPlugin.getWorkspace();
and resolve it to an absolute path
IWorkspaceRoot wsRoot = workspace.getRoot();
IPath wsPath = wsRoot.getRawLocation();
IPath absoluteWsPath = wsPath.makeAbsolute();