hu.ibello.transform

Interface CsvTransformer

public interface CsvTransformer

Utility class which transforms CSV into a list of java objects and back.

Author:

Kornél Simon

Method Summary

Modifier and Type	Method and Description
<T> List<T>	fromCsv(File file, Class<T> typeOfT) This method reads the given CSV data from a file and loads it into a list.
<T> List<T>	fromCsv(Reader csv, Class<T> typeOfT) This method reads the given CSV data and loads it into a list.
<T> List<T>	fromCsv(String csv, Class<T> typeOfT) This method reads the given CSV data and loads it into a list.
<T> void	toCsv(File file, List<? extends T> rows, Class<T> typeOfT) Transforms the given object list into a CSV data and write it into the given file.
<T> String	toCsv(List<? extends T> rows, Class<T> typeOfT) Transforms the given object list into a CSV data and returns it.
<T> void	toCsv(OutputStream stream, List<? extends T> rows, Class<T> typeOfT) Transforms the given object list into a CSV data and write it into the given stream.

Method Detail

fromCsv

<T> List<T> fromCsv(String csv,
                    Class<T> typeOfT)
             throws TransformerException

This method reads the given CSV data and loads it into a list. The first line in the CSV should be the header. Every other lines will be considered as new object in the list, with the given type.

Type Parameters:

T - type of the result objects

Parameters:

csv - the CSV content

typeOfT - type of the result objects

Returns:

list of objects

Throws:

TransformerException - if csv is not a valid CSV data

fromCsv

<T> List<T> fromCsv(Reader csv,
                    Class<T> typeOfT)
             throws TransformerException

This method reads the given CSV data and loads it into a list. The first line in the CSV should be the header. Every other lines will be considered as new object in the list, with the given type.

Type Parameters:

T - type of the result objects

Parameters:

csv - the Reader containing CSV data

typeOfT - type of the objects

Returns:

list of objects

Throws:

TransformerException - if csv is not a valid CSV data

fromCsv

<T> List<T> fromCsv(File file,
                    Class<T> typeOfT)
             throws TransformerException

This method reads the given CSV data from a file and loads it into a list. The first line in the CSV should be the header. Every other lines will be considered as new object in the list, with the given type.

Type Parameters:

T - type of the result objects

Parameters:

file - the file which contains the CSV data

typeOfT - type of the objects

Returns:

list of objects

Throws:

TransformerException - if csv is not a valid CSV file

toCsv

<T> String toCsv(List<? extends T> rows,
                 Class<T> typeOfT)
          throws TransformerException

Transforms the given object list into a CSV data and returns it. The header will be automatically extracted from the given class. Each fields of this class and it's superclasses will be considered as CSV columns, except:

• transient fields,
• fields from Object class.

The cell separator will be the , (comma) character.

Type Parameters:

T - type of the objects

Parameters:

rows - the list of objects

typeOfT - the class which will be used to construct the header

Returns:

the CSV data

Throws:

TransformerException - if one of the fields cannot be transformed to CSV value

toCsv

<T> void toCsv(OutputStream stream,
               List<? extends T> rows,
               Class<T> typeOfT)
        throws TransformerException

Transforms the given object list into a CSV data and write it into the given stream. The header will be automatically extracted from the given class. Each fields of this class and it's superclasses will be considered as CSV columns, except:

• transient fields,
• fields from Object class.

The cell separator will be the , (comma) character. The charset of the data will be UTF-8.

Type Parameters:

T - type of the objects

Parameters:

stream - the stream which will receive the CSV data

rows - the list of objects

typeOfT - the class which will be used to construct the header

Throws:

TransformerException - if one of the fields cannot be transformed to CSV value of there was an error writing into the stream

toCsv

<T> void toCsv(File file,
               List<? extends T> rows,
               Class<T> typeOfT)
        throws TransformerException

Transforms the given object list into a CSV data and write it into the given file. The header will be automatically extracted from the given class. Each fields of this class and it's superclasses will be considered as CSV columns, except:

• transient fields,
• fields from Object class.

The cell separator will be the , (comma) character. The charset of the data will be UTF-8.

Type Parameters:

T - type of the objects

Parameters:

file - the CSV file

rows - the list of objects

typeOfT - the class which will be used to construct the header

Throws:

TransformerException - if one of the fields cannot be transformed to CSV value of there was an error writing into the file