java - Programmatically list open projects in an eclipse workspace from outside of eclipse

Question

I want to write a Gradle plugin which can inspect an eclipse workspace directory and iterate over the open projects within the workspace and determine the location of each.

Something like

Workspace workspace = EclipseUtils.parseWorkspace("c:/myEclipseWorkspace");
Collection<Project> projects = workspace.getProjects();
for (Project project : projects) {
   System.out.println(String.format("name=%s, location=%s, open=%s",
      project.getName(), project.getLocation(), project.isOpen()));
}

I've looked at my workspace and can see some .location files under c:myEclipseWorkspace.metadata.pluginsorg.eclipse.core.resources.projects

But these files are a custom binary format

Is there an eclipse API that I can invoke to parse these? Or some other solution to iterate the open projects in a workspace.

Please note that I want to do this externally to eclipse and NOT within an eclipse plugin.

Answer 1

Reading the Private Description to Obtain Location

Since you are writing in Java, then reuse the Eclipse code from your external location.

i.e. Pull out some of the key code from org.eclipse.core.resources.ResourcesPlugin. Start with the impl of org.eclipse.core.resources.ResourcesPlugin.getWorkspace() and then work your way to org.eclipse.core.resources.IWorkspaceRoot.getProjects()

The above code reads the project description here: org.eclipse.core.internal.resources.LocalMetaArea.readPrivateDescription(IProject, ProjectDescription) and that is called from org.eclipse.core.internal.localstore.FileSystemResourceManager.read(IProject, boolean) which has some logic about default locations.

This is the joy of EPL, as long as your new program/feature is EPL you can reuse Eclipse's core code to do new and wonderful things.

Reading Workspace State to Obtain Open/Close State

When reading workspace state, you are moving into the ElementTree data structures. Reading this without using the ElementTree classes is probably unrealistic. Using the ElementTree classes without full OSGi is probably unrealistic. I provide the following notes to help you on your way.

Working backwards:

• ICoreConstants.M_OPEN is the flag value indicating project is open or closed (set for open, clear for closed)
• M_OPEN is tested when Project.isOpen() is called
• The flags at runtime are in ResourceInfo.flags
• The flags are loaded by ResourceInfo.readFrom() called from SaveManager.readElement()
• The DataInput input passed to readElement is from the Element Tree stored in the workspace meta directory in .metadata/.plugins/org.eclipse.core.resources/.root/<id>.tree. The specific version (id) of the file to use is recorded in the safe table .metadata/.plugins/org.eclipse.core.resources/.safetable/org.eclipse.core.resources
• The safe table is part of the SaveManager's internal state stored in a MasterTable