public synchronized BasicSubsystem getRootSubsystem()

in subsystem/subsystem-core/src/main/java/org/apache/aries/subsystem/core/internal/Subsystems.java [100:172]
66 lines of code
9 McCabe index (conditional complexity)

	public synchronized BasicSubsystem getRootSubsystem() {
		if (root == null) {
			File file = Activator.getInstance().getBundleContext().getDataFile("");
			File[] fileArray = file.listFiles();
			List<File> fileList = new ArrayList<File>(Arrays.asList(fileArray));
			Collections.sort(fileList, new Comparator<File>() {
				@Override
				public int compare(File file1, File file2) {
					String name1 = file1.getName();
					String name2 = file2.getName();
					return Long.valueOf(name1).compareTo(Long.valueOf(name2));
				}
			});
			if (fileList.isEmpty()) {
				// There are no persisted subsystems, including root.
				SubsystemResource resource;
				try {
					resource = new SubsystemResource(file);
				}
				catch (SubsystemException e) {
					throw e;
				}
				catch (Exception e) {
					throw new SubsystemException(e);
				}
				Coordination coordination = Utils.createCoordination();
				try {
					root = new BasicSubsystem(resource);
					// TODO This initialization is a bit brittle. The root subsystem
					// must be gotten before anything else will be able to use the
					// graph. At the very least, throw IllegalStateException where
					// appropriate.
					graph = new SubsystemGraph(root);
					ResourceInstaller.newInstance(coordination, root, root).install();
					populateRootSubsystem(root, coordination);
				} catch (Exception e) {
					coordination.fail(e);
				} finally {
					coordination.end();
				}
			}
			else {
				// There are persisted subsystems.
				Coordination coordination = Utils.createCoordination();
				Collection<BasicSubsystem> subsystems = new ArrayList<BasicSubsystem>(fileList.size());
				try {
					for (File f : fileList) {
						BasicSubsystem s = new BasicSubsystem(f);
						if (State.UNINSTALLED.equals(s.getState())) {
							// left over cache, delete this
							IOUtils.deleteRecursive(f);
						} else {
							subsystems.add(s);
							addSubsystem(s);
						}
					}
					root = getSubsystemById(0);
					SubsystemIdentifier.setLastId(
							Long.parseLong(
									root.getDeploymentManifest().getHeaders().get(
											DeploymentManifest.ARIESSUBSYSTEM_LASTID).getValue()));
					graph = new SubsystemGraph(root);
					ResourceInstaller.newInstance(coordination, root, root).install();
					populateRootSubsystem(root, coordination);
				} catch (Exception e) {
					coordination.fail(e);
				} finally {
					coordination.end();
				}
			}
		}
		return root;
	}