sirius.kernel.commons

Class CSVReader

java.lang.Object

sirius.kernel.commons.CSVReader

public class CSVReader
extends Object

Provides a simple reader which parses given CSV (comma separated values) data into rows.

By default ; is used to separate columns and a line break (either Windows or Unix) is used to separate rows. Also columns can be enclosed in quotations, especially if line breaks occur within a value. The default character used to signal quaotation is ". Note that the quotation symbol has to be the first non-whitespace character in the column to be detected as such (or the very first character if notIgnoringWhitespaces() was called during initialisation).

Furthermore escaping can be used to embed a column separator or a quotation character in a column value. By default \ is used as escape character.

Empty columns will be represented as empty strings. Values will not be trimmed, as this can be easily achieved using the Values which is used to represent a parsed row.

An example use case would be: new CSVReader(someInput).execute(row -> doSomethingSmartPerRow(row));

Note that this class checks the TaskContext during execution. Therefore if the underlying task is cancelled, the parser will stop after the current row has been processed.

Constructor Summary

Constructors

Constructor and Description
CSVReader(Reader input) Creates a new reader which processes the given input.

Method Summary

Modifier and Type	Method and Description
void	execute(Consumer<Values> consumer) Parses the previously supplied input and calls the given consumer for each row.
boolean	isEOF()
CSVReader	notIgnoringWhitespaces() Disables the flexible whitespace behaviour.
CSVReader	withEscape(char escape) Specifies the escape character to use.
CSVReader	withQuotation(char quotation) Specifies the quotation character to use.
CSVReader	withSeparator(char separator) Specifies the separator character to use.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CSVReader

public CSVReader(@Nonnull
                 Reader input)

Creates a new reader which processes the given input.

Note that the given input is consumed character by character so using a BufferedReader might be a good idea as most devices rather exchange larger blocks of data (e.g. 8kb).

If execute(Consumer) is invoked, the given input will be closed once all data has been parsed or if and IO error occurs.

Parameters:

input - the input to parse

Method Detail

withSeparator

public CSVReader withSeparator(char separator)

Specifies the separator character to use.

By default this is ;.

Parameters:

separator - the separator to use

Returns:

the reader itself for fluent method calls

withQuotation

public CSVReader withQuotation(char quotation)

Specifies the quotation character to use.

By default this is ". Use \0 to disable quotation entirely.

Parameters:

quotation - the quotation character to use

Returns:

the reader itself for fluent method calls

withEscape

public CSVReader withEscape(char escape)

Specifies the escape character to use.

By default this is \. Use \0 to disable escaping entirely.

Parameters:

escape - the escape character to use

Returns:

the reader itself for fluent method calls

notIgnoringWhitespaces

public CSVReader notIgnoringWhitespaces()

Disables the flexible whitespace behaviour.

If a column starts with whitespaces (space or tab characters) and is then quoted, the whitespaces around the quotes are simply ignored. Therefore ;"a";, ; "a" ; and ;a; will yield the same result. However ; a ; will keep the whitespaces and has to be manually trimmed.

Calling this method will disable this behavior and ; "a" ; will yield "a" as column value instead of a.

Returns:

the reader itself for fluent method calls

execute

public void execute(Consumer<Values> consumer)
             throws IOException

Parses the previously supplied input and calls the given consumer for each row.

Note that this method will close the given input.

Parameters:

consumer - the consume to call for each line

Throws:

IOException - if an IO error occures while reading from the given input

isEOF

public boolean isEOF()