Документация

classdef MyDatastore < matlab.io.Datastore
    
    properties (Access = private)
        CurrentFileIndex double
        FileSet matlab.io.datastore.DsFileSet
    end

    % Property to support saving, loading, and processing of
    % datastore on different file system machines or clusters. 
    % In addition, define the methods get.AlternateFileSystemRoots()
    % and set.AlternateFileSystemRoots() in the methods section. 
    properties(Dependent)
        AlternateFileSystemRoots
    end

    methods % begin methods section
        
        function myds = MyDatastore(location,altRoots)
            myds.FileSet = matlab.io.datastore.DsFileSet(location,...
                'FileExtensions','.bin', ...
                'FileSplitSize',8*1024);
            myds.CurrentFileIndex = 1;
            
            if nargin == 2
                 myds.AlternateFileSystemRoots = altRoots;
            end

            reset(myds);
        end

        function tf = hasdata(myds)
            % Return true if more data is available.
            tf = hasfile(myds.FileSet);
        end

        function [data,info] = read(myds)
            % Read data and information about the extracted data.
            if ~hasdata(myds)
                error(sprintf(['No more data to read.\nUse the reset ',...
                    'method to reset the datastore to the start of ' ,...
                    'the data. \nBefore calling the read method, ',...
                    'check if data is available to read ',...
                    'by using the hasdata method.']))
                
            end
            
            fileInfoTbl = nextfile(myds.FileSet);
            data = MyFileReader(fileInfoTbl);
            info.Size = size(data);
            info.FileName = fileInfoTbl.FileName;
            info.Offset = fileInfoTbl.Offset;
            
            % Update CurrentFileIndex for tracking progress
            if fileInfoTbl.Offset + fileInfoTbl.SplitSize >= ...
                    fileInfoTbl.FileSize
                myds.CurrentFileIndex = myds.CurrentFileIndex + 1 ;
            end
            
            
        end

        function reset(myds)
            % Reset to the start of the data.
            reset(myds.FileSet);
            myds.CurrentFileIndex = 1;
        end

        % Before defining these methods, add the AlternateFileSystemRoots 
        % property in the properties section 
    
        % Getter for AlternateFileSystemRoots property
        function altRoots = get.AlternateFileSystemRoots(myds)
            altRoots = myds.FileSet.AlternateFileSystemRoots;
        end

        % Setter for AlternateFileSystemRoots property
        function set.AlternateFileSystemRoots(myds,altRoots)
            try
              % The DsFileSet object manages the AlternateFileSystemRoots
              % for your datastore
              myds.FileSet.AlternateFileSystemRoots = altRoots;

              % Reset the datastore
              reset(myds);  
            catch ME
              throw(ME);
            end
        end
        
    end

    methods (Hidden = true)
        function frac = progress(myds)
            % Determine percentage of data read from datastore
            if hasdata(myds) 
               frac = (myds.CurrentFileIndex-1)/...
                             myds.FileSet.NumFiles; 
            else 
              frac = 1;  
            end 
        end
    end

    methods (Access = protected)
        % If you use the DsFileSet object as a property, then 
        % you must define the copyElement method. The copyElement
        % method allows methods such as readall and preview to 
        % remain stateless
        function dscopy = copyElement(ds)
            dscopy = copyElement@matlab.mixin.Copyable(ds);
            dscopy.FileSet = copy(ds.FileSet);
        end
    end

end

classdef MyDatastore < matlab.io.Datastore & ...
                       matlab.io.datastore.Partitionable
     .
     .
     . 
  

 methods
     .
     .
     .
     function subds = partition(myds,n,ii)
         subds = copy(myds);
         subds.FileSet = partition(myds.FileSet,n,ii);
         reset(subds);         
     end
 end

 methods (Access = protected)
     function n = maxpartitions(myds) 
       n = maxpartitions(myds.FileSet); 
     end     
 end 

end  

classdef MyDatastore < matlab.io.Datastore & ...
                       matlab.io.datastore.HadoopLocationBased 
     .
     .
     . 
  

 methods (Hidden = true)
     .
     .
     .   

     function initializeDatastore(myds,hadoopInfo)
        import matlab.io.datastore.DsFileSet;
        myds.FileSet = DsFileSet(hadoopInfo,...
             'FileSplitSize',myds.FileSet.FileSplitSize);
        reset(myds);         
     end 
     
     function loc = getLocation(myds)
        loc = myds.FileSet;         
     end 
     
     % isfullfile method is optional
     function tf = isfullfile(myds)
        tf = isequal(myds.FileSet.FileSplitSize,'file');          
     end 
 
 end

end

classdef MyDatastore < matlab.io.Datastore & ...
                      matlab.io.datastore.Shuffleable 
     .
     .
     . 
  

  methods

        % previously defined methods
        .
        .
        . 
   
        function dsNew = shuffle(ds)
            % dsNew = shuffle(ds) shuffles the files and the
            % corresponding labels in the datastore.
            
            % Create a copy of datastore
            dsNew = copy(ds);
            dsNew.Datastore = copy(ds.Datastore);
            fds = dsNew.Datastore;
            
            % Shuffle files and corresponding labels
            numObservations = dsNew.NumObservations;
            idx = randperm(numObservations);
            fds.Files = fds.Files(idx);
            dsNew.Labels = dsNew.Labels(idx);
        end

  end

end

classdef MyDatastore < matlab.io.Datastore & ...
                       matlab.io.datastore.FileWritable 
     .
     .
     . 
  

    properties (Constant)
        SupportedOutputFormats = ...
       [matlab.io.datastore.ImageDatastore.SupportedOutputFormats, "dcm"];
        DefaultOutputFormat = "dcm";
    end

    methods (Access = protected)
        function files = getFiles(ds)
            files = {'data/folder/file1', 'data/folder/file2',...};
        end
        function folders = getFolders(ds)
            folders = {'data/folder1/', 'data/folder2/',...};
        end
    end

    methods(Access = protected)        
        function tf = write(myds, data, writeInfo, outFmt, varargin)
            if outFmt == "dcm" % use custom write fcn for dcm format
                dicomwrite(data, writeInfo.SuggestedOutputName, varargin{:});
            else % callback into built-in for known formats
                write@matlab.io.datastore.FileWritable(myds, data, ...
                    writeInfo, outFmt, varargin{:});
            end
            tf = true;
        end
    end

end