Module io.jenetics.ext

Package io.jenetics.ext.util

Class CsvSupport.LineSplitter

java.lang.Object

io.jenetics.ext.util.CsvSupport.LineSplitter

Enclosing class:

CsvSupport

public static final class CsvSupport.LineSplitter
extends Object

Splitting a CSV line into columns (records).

Examples

Simple usage

final var reader = new LineReader();
final var splitter = new LineSplitter(new Separator(','));
final List<String[]> rows;
try (Stream<String> lines = reader.read(CharBuffer.wrap(csv))) {
	rows = lines
		.map(splitter::split)
		.toList();
}

Projecting and re-ordering columns

final var csv = """
	Country,City,AccentCity,Region,Population,Latitude,Longitude
	ad,aixas,Aixàs,06,,42.4833333,1.4666667
	ad,aixirivali,Aixirivali,06,,42.4666667,1.5
	ad,aixirivall,Aixirivall,06,,42.4666667,1.5
	ad,aixirvall,Aixirvall,06,,42.4666667,1.5
	ad,aixovall,Aixovall,06,,42.4666667,1.4833333
	""";

final var reader = new LineReader();

// Only read three columns, in the specified order.
final var projection = new ColumnIndexes(
	// Read 'Region' as first column.
	3,
	// Read 'City' as second column.
	1,
	// Read 'Country' as third column.
	0
);

// Configure the splitter with default separator and quote character,
// and make it return only the specified columns in the defined order.
final var splitter = new LineSplitter(projection);

try (Stream<String> lines = reader.read(CharBuffer.wrap(csv))) {
	final var result = lines
		.map(splitter::split)
		.map(Arrays::toString)
		.collect(Collectors.joining("\n", "", "\n"));

	assert result.equals("""
		[Region, City, Country]
		[06, aixas, ad]
		[06, aixirivali, ad]
		[06, aixirivall, ad]
		[06, aixirvall, ad]
		[06, aixovall, ad]
		"""
	);
}

Since:

8.1

Version:

8.1

API Note:

A line splitter ist not thread-safe and can't be shared between different threads.

Implementation Note:

The split String[] array will never contain null values. Empty columns will be returned as empty strings.

Constructor Summary

Constructors

Constructor	Description
LineSplitter()	Create a new line splitter with default values.
LineSplitter(CsvSupport.ColumnIndexes projection)	Create a new line splitter with the given parameters.
LineSplitter(CsvSupport.Quote quote)	Create a new line splitter with the given parameters.
LineSplitter(CsvSupport.Separator separator)	Create a new line splitter with the given parameters.
LineSplitter(CsvSupport.Separator separator, CsvSupport.Quote quote)	Create a new line splitter with the given parameters.
LineSplitter(CsvSupport.Separator separator, CsvSupport.Quote quote, CsvSupport.ColumnIndexes projection)	Create a new line splitter with the given parameters.

Method Summary

Modifier and Type	Method	Description
String[]	split(CharSequence line)	Splitting the given CSV line into its columns.

Methods inherited from class java.lang.Object

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

Constructor Details

LineSplitter

public LineSplitter(CsvSupport.Separator separator,
 CsvSupport.Quote quote,
 CsvSupport.ColumnIndexes projection)

Create a new line splitter with the given parameters.

Parameters:

separator - the separator character used by the CSV line to split

quote - the quote character used by the CSV line to split

projection - the column indexes which should be part of the split result

Throws:

NullPointerException - if one of the parameters is null

LineSplitter

public LineSplitter(CsvSupport.Separator separator,
 CsvSupport.Quote quote)

Create a new line splitter with the given parameters.

Parameters:

separator - the separator character used by the CSV line to split

quote - the quote character used by the CSV line to split

Throws:

NullPointerException - if one of the parameters is null

LineSplitter

public LineSplitter(CsvSupport.Separator separator)

Create a new line splitter with the given parameters. The default quote character, CsvSupport.Quote.DEFAULT, will be used by the created splitter.

Parameters:

separator - the separator character used by the CSV line to split

Throws:

NullPointerException - if one of the parameters is null

LineSplitter

public LineSplitter(CsvSupport.Quote quote)

Create a new line splitter with the given parameters. The default separator character, CsvSupport.Separator.DEFAULT, will be used by the created splitter.

Parameters:

quote - the quote character used by the CSV line to split

Throws:

NullPointerException - if one of the parameters is null

LineSplitter

public LineSplitter(CsvSupport.ColumnIndexes projection)

Create a new line splitter with the given parameters. Only the defined columns will be part of the split result and the default separator character, CsvSupport.Separator.DEFAULT, and default quote character, CsvSupport.Quote.DEFAULT, is used by the created splitter.

Parameters:

projection - the column indexes which should be part of the split result

Throws:

NullPointerException - if one of the parameters is null

LineSplitter

public LineSplitter()

Create a new line splitter with default values.

Method Details

split

public String[] split(CharSequence line)

Splitting the given CSV line into its columns.

Parameters:

line - the CSV line to split

Returns:

the split CSV columns

Throws:

NullPointerException - if the CSV line is null

Implementation Note:

The split String[] array will never contain null values. Empty columns will be returned as empty strings.