EDIT

package eu.etaxonomy.taxeditor.security;

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Observable;

import java.util.Observer;

import org.eclipse.ui.AbstractSourceProvider;

import org.eclipse.ui.ISources;

import org.springframework.security.core.Authentication;

import org.springframework.security.core.GrantedAuthority;

import eu.etaxonomy.cdm.persistence.permission.Role;

import eu.etaxonomy.taxeditor.store.CdmStore;

import eu.etaxonomy.taxeditor.store.LoginManager;

/**

 * Provides the Roles assigned to the currently authenticated principal as the

 * variable {@code eu.etaxonomy.taxeditor.security.userRoles}

 *

 * @author a.kohlbecker

 */

public class AuthenticationSourceProvider extends AbstractSourceProvider implements Observer {

	public final static String USER_ROLES_VARIABLE = "eu.etaxonomy.taxeditor.security.userRoles";

	public final static String USER_NAME_VARIABLE = "eu.etaxonomy.taxeditor.security.userName";

	public final static String USER_VARIABLE = "eu.etaxonomy.taxeditor.security.user";

	private final static String[] PROVIDED_SOURCE_NAMES = new String[] {

	    USER_ROLES_VARIABLE,

	    USER_NAME_VARIABLE,

	    USER_VARIABLE

	    };

	private final static Map<String, Object> stateMap = new HashMap<String, Object>();

	public AuthenticationSourceProvider() {

		super();

		initialize();

	}

	private void initialize() {

		CdmStore.getLoginManager().addObserver(this);

	}

	@Override

	public void dispose() {

		CdmStore.getLoginManager().deleteObserver(this);

	}

	@Override

	public Map getCurrentState() {

		// SecurityContextHolder.getContext().

		List<Role> roles = getCurrentAuthenticationsRoles();

		List<String> rolesStr = new ArrayList<String>(roles.size());

		for(Role r : roles){

			rolesStr.add(r.getAuthority());

		}

		stateMap.put(USER_ROLES_VARIABLE, rolesStr);

		stateMap.put(USER_VARIABLE, getCurrentAutheticationPrincipal());

		stateMap.put(USER_NAME_VARIABLE, getCurrentAutheticationName());

		return stateMap;

	}

    private String getCurrentAutheticationName() {

        Authentication authentication = CdmStore.getCurrentAuthentiation();

        if (authentication != null) {

            return authentication.getName();

        }

        return null;

    }

    /**

     * @return most probably a Cdm User instance or null

     */

    private Object getCurrentAutheticationPrincipal() {

        Authentication authentication = CdmStore.getCurrentAuthentiation();

        if (authentication != null) {

            return authentication.getPrincipal();

        }

        return null;

    }

    /*

	 * TODO refactor into User once Role is a model class

	 */

	private List<Role> getCurrentAuthenticationsRoles() {

		List<Role> roles = new ArrayList<>();

		Authentication authentication = CdmStore.getCurrentAuthentiation();

		if (authentication == null) {

			return roles;

		}

		Collection<? extends GrantedAuthority> authorities = authentication

				.getAuthorities();

		if (authorities == null) {

			return roles;

		}

		Role role = null;

		for (GrantedAuthority ga : authorities) {

			try {

				// check if it is a valid role

				role = Role.fromString(ga.getAuthority());

				if (role != null) {

					roles.add(role);

				}

			} catch (Exception e) {

				/* IGNORE */

			}

		}

		return roles;

	}

	@Override

    public String[] getProvidedSourceNames() {

		return PROVIDED_SOURCE_NAMES;

	}

	@Override

	public void update(Observable o, Object arg) {

		if(o instanceof LoginManager){

			/*

			 * This triggers an update of the variable state, and will update also

			 * all listeners to the evaluation service. So that every menu point,

			 * which is also expression controlled, gets updated too.

			 */

			fireSourceChanged(ISources.WORKBENCH, getCurrentState());

		}

	}

}