Set searches = new HashSet();
searches.add( usernamesInRoleSearch );
searches.add( usernamesInRoleSearch2 );
UnionizingLdapSearch unionSearch = new UnionizingLdapSearch( searches );
unionSearch.afterPropertiesSet();
DefaultLdapUserRoleListService userRoleListService = new DefaultLdapUserRoleListService();
userRoleListService.setUsernamesInRoleSearch( unionSearch );