The matlab.metadata.Property Object

Use the matlab.metadata.Property class to determine the values of property attributes. The writable properties of a matlab.metadata.Property object correspond to the attributes of the associated property. The values of the writable matlab.metadata.Property properties correspond to the attribute values specified in the class definition.

You can get the matlab.metadata.Property object for a property from the matlab.metadata.Class object. To get the matlab.metadata.Class object for a class:

For example, the BasicHandle class defines one public and two private properties:

classdef BasicHandle < handle
   % BasicHandle  Inherits from handle superclass
   % Defines 1 public and 2 private properties.
   properties (SetAccess = private)
      Date = date
      PassKey = randi(9,[1,7]) 
   end
   properties
      Category {mustBeMember(Category,{'new','change'})} = 'new'
   end
end

Create the matlab.metadata.Class object using the ? operator with the class name:

mc = ?BasicHandle

mc = 

  Class with properties:

                    Name: 'BasicHandle'
             Description: 'Inherits from handle superclass'
     DetailedDescription: '  Defines 1 public and 2 private properties.'
                  Hidden: 0
                  Sealed: 0
                Abstract: 0
             Enumeration: 0
         ConstructOnLoad: 0
        HandleCompatible: 1
         InferiorClasses: [0×1 matlab.metadata.Class]
               Namespace: [0×0 matlab.metadata.Namespace]
                 Aliases: [0×1 string]
    RestrictsSubclassing: 0
            PropertyList: [3×1 matlab.metadata.Property]
              MethodList: [24×1 matlab.metadata.Method]
               EventList: [1×1 matlab.metadata.Event]
   EnumerationMemberList: [0×1 matlab.metadata.EnumerationMember]
          SuperclassList: [1×1 matlab.metadata.Class]

The matlab.metadata.Class object property named PropertyList contains an array of matlab.metadata.Property objects, one for each property defined by the class. For example, the name of the property associated with the matlab.metadata.Property object in element 1 is:

mc.PropertyList(1).Name

ans =

Date

The matlab.metadata.Class object contains a matlab.metadata.Property object for all properties, including hidden properties. The properties function returns only public properties.

For a handle class, use the handle findprop method to get the matlab.metadata.Property object for a specific property.

For example, find the matlab.metadata.Property object for the Category property of the BasicHandle class.

h = BasicHandle;
mp = findprop(h,'Category')

mp = 

  Property with properties:

                    Name: 'Category'
             Description: ''
     DetailedDescription: ''
               GetAccess: 'public'
               SetAccess: 'public'
               Dependent: 0
                Constant: 0
                Abstract: 0
               Transient: 0
                  Hidden: 0
           GetObservable: 0
           SetObservable: 0
                AbortSet: 0
             NonCopyable: 0
    PartialMatchPriority: 1
               GetMethod: []
               SetMethod: []
              HasDefault: 1
            DefaultValue: 'new'
              Validation: [1×1 matlab.metadata.Validation]
           DefiningClass: [1×1 matlab.metadata.Class]

The matlab.metadata.Property display shows that a default BasicHandle object Category property:

For a list of property attributes, see Table of Property Attributes.

mc = ?containers.Map;

class(mc)

ans =

matlab.metadata.Class

class(mc.PropertyList)

ans =

matlab.metadata.Property

mc.Properties(1)

ans = 

    [1x1 matlab.metadata.Property]

class(mc.PropertyList(1).Name)

ans =

char

mc.PropertyList(1).Name([1 end])

ans =

Ct

How to Find Properties with Specific Attributes

This example implements a function that finds properties with specific attribute values. For example, you can:

The findAttrValue function returns a cell array of property names that set the specified attribute. The function accesses information from metadata using these techniques:

function cl_out = findAttrValue(obj,attrName,varargin)
   if ischar(obj)
      mc = matlab.metadata.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
      end
   end
   cl_out = cl_array(1:ii);
end

mapobj = containers.Map({'rose','bicycle'},{'flower','machine'});

findAttrValue(mapobj,'SetAccess','private')

ans = 

    'Count'    'KeyType'    'ValueType'    'serialization'

findAttrValue(mapobj,'GetAccess','public')

ans = 

    'Count'    'KeyType'    'ValueType'