uk.ac.starlink.table.formats

Class CsvStarTable

java.lang.Object

uk.ac.starlink.table.AbstractStarTable

uk.ac.starlink.table.formats.StreamStarTable

uk.ac.starlink.table.formats.CsvStarTable

All Implemented Interfaces:

Closeable, AutoCloseable, StarTable

public class CsvStarTable
extends StreamStarTable

Comma-Separated Value table. This reader tries to read data in the semi-standard CSV format. The intention is that it understands the version of that dialect spoken by MS Excel, though the documentation on which it is based was not obtained directly from MicroSoft.

Here are the rules:

• Each row must have the same number of comma-separated fields.
• Whitespace (space or tab) adjacent to a comma is ignored.
• Adjacent commas, or a comma at the start or end of a line (whitespace apart) indicates a null field.
• Lines are terminated by any sequence of carriage-return or newline characters ('\r' or '\n') (a corollary of this is that blank lines are ignored).
• Cells may be enclosed in double quotes; quoted values may contain linebreaks (or any other character); a double quote character within a quoted value is represented by two adjacent double quotes.
• The first line may be a header line containing column names rather than a row of data. Exactly the same syntactic rules are followed for such a row as for data rows.

Since:

21 Sep 2004

Author:

Mark Taylor (Starlink)

Field Summary

Fields inherited from class uk.ac.starlink.table.formats.StreamStarTable

END

Constructor Summary

Constructors

Constructor and Description
CsvStarTable(DataSource datsrc) Constructor with default options.
CsvStarTable(DataSource datsrc, Boolean fixHasHeaderLine, int maxSample) Constructor with configuration option.

Method Summary

Modifier and Type	Method and Description
protected PushbackInputStream	getInputStream() Convenience method which returns a buffered pushback stream based on this table's data source.
protected RowEvaluator.Metadata	obtainMetadata() Obtains column metadata for this table, probably by reading through the rows once and using a RowEvaluator.
protected List<String>	readRow(PushbackInputStream in) Reads the next row of data from a given stream.

Methods inherited from class uk.ac.starlink.table.formats.StreamStarTable

getColumnCount, getColumnInfo, getRowCount, getRowSequence, init

Methods inherited from class uk.ac.starlink.table.AbstractStarTable

checkedLongToInt, close, getCell, getColumnAuxDataInfos, getName, getParameters, getRow, getRowAccess, getRowSplittable, getURL, isRandom, setName, setParameters, setURL

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.table.StarTable

getParameterByName, setParameter

Constructor Detail

CsvStarTable

public CsvStarTable(DataSource datsrc)
             throws TableFormatException,
                    IOException

Constructor with default options.

Parameters:

datsrc - data source

Throws:

TableFormatException

IOException

CsvStarTable

public CsvStarTable(DataSource datsrc,
                    Boolean fixHasHeaderLine,
                    int maxSample)
             throws TableFormatException,
                    IOException

Constructor with configuration option.

Parameters:

datsrc - data source

fixHasHeaderLine - indicates whether initial line is known to be column names: yes, no or auto-determine

maxSample - maximum number of rows sampled to determine column data types; if <=0, all rows are sampled

Throws:

TableFormatException

IOException

Method Detail

getInputStream

protected PushbackInputStream getInputStream()
                                      throws IOException

Description copied from class: StreamStarTable

Convenience method which returns a buffered pushback stream based on this table's data source.

Overrides:

getInputStream in class StreamStarTable

Returns:

input stream containing source data

Throws:

IOException

obtainMetadata

protected RowEvaluator.Metadata obtainMetadata()
                                        throws TableFormatException,
                                               IOException

Description copied from class: StreamStarTable

Obtains column metadata for this table, probably by reading through the rows once and using a RowEvaluator.

Specified by:

obtainMetadata in class StreamStarTable

Returns:

information about the table represented by the character stream

Throws:

TableFormatException - if the data doesn't represent this kind of table

IOException - if I/O error is encountered

readRow

protected List<String> readRow(PushbackInputStream in)
                        throws IOException

Reads the next row of data from a given stream. Ignorable rows are skipped; comments may be stashed away.

Specified by:

readRow in class StreamStarTable

Parameters:

in - input stream

Returns:

list of Strings one for each cell in the row, or null for end of stream

Throws:

TableFormatException - if the data doesn't represent this kind of table

IOException - if I/O error is encountered