MATLAB Object-Oriented Programming

The findAttrValue function returns a cell array of property names that set the

specified attribute.

The findAttrValue function accesses information from metadata using these

techniques:

• If input argument, obj, is a char vector, use the meta.class.fromName static
  method to get the meta.class object.


• If input argument, obj, is an object, use the metaclass function to get the
  meta.class object.


• Every property has an associated meta.property object. Obtain these objects from
  the meta.class PropertyList property.


• Use the handle class findprop method to determine if the requested property
  attribute is a valid attribute name. All property attributes are properties of the
  meta.property object. The statement, findobj(mp,'PropertyName') determines
  whether the meta.property object, mp, has a property called PropertyName.


• Reference meta.property object properties using dynamic field names. For example,
  if attrName = 'Constant', then MATLAB converts the expression mp.(attrName)
  to mp.Constant


• The optional third argument enables you to specify the value of attributes whose
  values are not logical true or false (such as GetAccess and SetAccess).

function cl_out = findAttrValue(obj,attrName,varargin)

if ischar(obj)

mc = meta.class.fromName(obj);

elseif isobject(obj)

mc = metaclass(obj);

end

ii = 0; numb_props = length(mc.PropertyList);

cl_array = cell(1,numb_props);

for c = 1:numb_props

mp = mc.PropertyList(c);

if isempty (findprop(mp,attrName))

error('Not a valid attribute name')

end

attrValue = mp.(attrName);

if attrValue

if islogical(attrValue) || strcmp(varargin{1},attrValue)

ii = ii + 1;

cl_array(ii) = {mp.Name};

end

16 Information from Class Metadata