EDIT

import java.util.List;

import org.eclipse.core.commands.operations.IUndoContext;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Status;

import org.eclipse.core.runtime.jobs.Job;

import org.eclipse.swt.widgets.Display;

import eu.etaxonomy.cdm.model.description.PolytomousKey;

import eu.etaxonomy.taxeditor.navigation.NavigationUtil;

import eu.etaxonomy.taxeditor.navigation.key.polytomous.PolytomousKeyViewPart;

import eu.etaxonomy.taxeditor.navigation.key.polytomous.operation.RefreshNodesOperation;

import eu.etaxonomy.taxeditor.operation.AbstractPostOperation;

		final PolytomousKeyViewPart view = (PolytomousKeyViewPart) NavigationUtil.getView(PolytomousKeyViewPart.ID, false);

		final List<PolytomousKey> keys = view.getKeys();

		final String label = Messages.RefreshPolytomousKeyNodesHandler_REFRESH;

		final IUndoContext undoContext = NavigationUtil.getUndoContext();

		if (keys.size() > 0) {

			Job job = new Job(REFRESHING_POLYTOMOUS_KEY_NODES){

					@Override

					protected IStatus run(IProgressMonitor monitor) {

						monitor.beginTask(REFRESHING_POLYTOMOUS_KEY_NODES, keys.size());

							for (final PolytomousKey key : keys) {

								if(key.getRoot() != null) {

									Display.getDefault().asyncExec(new Runnable(){

										@Override

										public void run() {

											AbstractPostOperation operation = new RefreshNodesOperation(label, undoContext, key, view);

											NavigationUtil.executeOperation(operation);

										}

									});

									monitor.worked(1);

								}

							}

							monitor.done();

							return Status.OK_STATUS;

						}

					};

					job.setPriority(Job.SHORT);

					job.schedule();

				}