classdef DataObj < MatrixObj
%DataObj - a subclass of MatrixObj
%
% See UserGuide for full details and examples.
%
% Sometimes it is desirable to customize or modify the behavior of other
% existing data types or classes. The DataObj subclass is tailored to situations
% like these. Instead of a "Params" property, this subclass contains a "Data"
% property for holding an object data variable. Typically, this would be an existing
% MATLAB numeric variable type, although this is not strictly necessary. When a function
% Ops.MethodName is called, the function will receive this Data variable as
% input, in place of the actual DataObj object. This is in contrast to MatrixObj
% Ops functions, which always receive the entire object as input.
% The result of a DataObj operation is also always a new DataObj
% object, one whose Data property holds the results of the computation. The function Ops.size()
% is an exception to this rule. The size() method will return normal numeric output.
% These ideas are demonstrated in the following example.
%
% EXAMPLE: In this example, DataObj is used to create a specialized
% array type which invokes bsxfun() for a variety of operations. This can be
% a useful way of circumventing bsxfun's lengthy functional syntax.
%
%
% P=DataObj;
% P.Data=[1,2;3,4].',
%
% P.Ops.minus=@(A,B) bsxfun(@minus,A,B);
% P.Ops.plus= @(A,B) bsxfun(@plus,A,B);
% P.Ops.times=@(A,B) bsxfun(@times,A,B);
% P.Ops.rdivide= @(A,B) bsxfun(@rdivide,A,B);
% P.Ops.ldivide= @(A,B) bsxfun(@ldivide,A,B);
% P.Ops.power=@(A,B) bsxfun(@power,A,B);
% P.Ops.eq=@(A,B) bsxfun(@eq,A,B);
% P.Ops.ne= @(A,B) bsxfun(@ne,A,B);
% P.Ops.lt=@(A,B) bsxfun(@lt,A,B);
% P.Ops.le= @(A,B) bsxfun(@le,A,B);
% P.Ops.gt= @(A,B) bsxfun(@gt,A,B);
% P.Ops.ge=@(A,B) bsxfun(@ge,A,B);
% P.Ops.and= @(A,B) bsxfun(@and,A,B);
% P.Ops.or=@(A,B) bsxfun(@or,A,B);
%
%
% Q=P-[1,2],
% R=P+[3;7],
%
% P =
%
% 1 3
% 2 4
%
%
% Q =
%
% 0 1
% 1 2
%
%
% R =
%
% 4 6
% 9 11
%
%
% Notice that the above P.Ops functions are written in terms of normal MATLAB
% numerical input variables. There is no need for these functions to extract
% the Data to be operated upon from the DataObj. This extraction is done by the
% DataObj class methods automatically.
%
%Copyright 2010-08-22, Matt Jacobson, Xoran Technologies, http://www.xorantech.com
%properties (Access=protected, Hidden=false)
properties (Constant=true, Hidden=true);
DefaultTemplate=DataObj.MakeDefaultTemplate;
end
methods (Access=protected, Hidden=true);
function Name=TemplateName(obj)
Name='DefaultTemplate';
end
end
properties
Data;
end
methods
function obj=DataObj(Data,varargin)
obj=obj@MatrixObj(varargin{:});
if nargin>=1
obj.Data=Data;
end
if length(varargin)<2
tmp=obj.DefaultTemplate;
Ops=struct(tmp{:});
obj.Ops=Ops;
end
end
end
methods (Static, Hidden, Access=protected)
function template=MakeDefaultTemplate
template=MatrixObj.OpsTemplate;
template(2,:)=cellfun(@(name) str2func(name), template(1,:), 'uni',0);
[idx,loc]=ismember({'display','subsref','subsasgn','subsindex','end'},...
template(1,:)); %some exceptions
template(2,loc)={[]};
end
end
end
