uk.ac.starlink.table.formats

Class CsvTableBuilder

java.lang.Object

uk.ac.starlink.table.formats.DocumentedTableBuilder

uk.ac.starlink.table.formats.RowEvaluatorTableBuilder

uk.ac.starlink.table.formats.CsvTableBuilder

All Implemented Interfaces:

Documented, DocumentedIOHandler, TableBuilder

public class CsvTableBuilder
extends RowEvaluatorTableBuilder

A table builder which reads tables in Comma-Separated Values format. The detailed format of input file which is understood is documented fully in the CsvStarTable class.

Since:

21 Sep 2004

Author:

Mark Taylor (Starlink)

Constructor Summary

Constructors

Constructor and Description
CsvTableBuilder()

Method Summary

Modifier and Type	Method and Description
boolean	docIncludesExample() Indicates whether the serialization of some (short) example table should be added to the user documentation for this handler.
char	getDelimiter() Returns the delimiter character.
String	getFormatName() Returns the name of the format which can be read by this handler.
Boolean	getHasHeader() Returns header interpretation policy.
String	getXmlDescription() Returns user-directed documentation in XML format.
StarTable	makeStarTable(DataSource datsrc, boolean wantRandom, StoragePolicy policy) Constructs a StarTable based on a given DataSource.
void	setDelimiter(char delimiter) Sets the delimiter character.
void	setHasHeader(Boolean hasHeader) Sets whether input CSV files are known to include the optional header line or not.

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

canImport, canStream, getDecoders, getMaxSample, setDecoderExcludeList, setDecoders, setMaxSample, streamStarTable

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

getExtensions, looksLikeFile

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.formats.DocumentedIOHandler

matchesExtension, readText, toLink

Constructor Detail

CsvTableBuilder

public CsvTableBuilder()

Method Detail

getFormatName

public String getFormatName()

Description copied from interface: TableBuilder

Returns the name of the format which can be read by this handler. Matching against this string may be used by callers to identify or select this handler from a list.

Returns:

one-word description of this handler's format

makeStarTable

public StarTable makeStarTable(DataSource datsrc,
                               boolean wantRandom,
                               StoragePolicy policy)
                        throws TableFormatException,
                               IOException

Description copied from interface: TableBuilder

Constructs a StarTable based on a given DataSource. If the source is not recognised or this builder does not know how to construct a table from it, then a TableFormatException should be thrown. If this builder thinks it should be able to handle the source but an error occurs during processing, an IOException can be thrown.

The wantRandom parameter is used to indicate whether, ideally, a random-access table should be returned. There is no requirement for the builder to honour this request, but if it knows how to make both random and non-random tables, it can use this flag to decide which to return.

Note: the presence of the wantRandom parameter is somewhat misleading. TableBuilder implementations usually should, and do, ignore it (it would be removed from the interface if it were not for backward compatibility issues). Regardless of the value of this parameter, implementations should return a random-access table only if it is easy for them to do so; in particular they should not use the supplied storagePolicy, or any other resource-expensive measure, to randomise a sequential table just because the wantRandom parameter is true.

Parameters:

datsrc - the DataSource containing the table resource

wantRandom - whether, preferentially, a random access table should be returned

policy - a StoragePolicy object which may be used to supply scratch storage if the builder needs it

Returns:

a StarTable made out of datsrc

Throws:

TableFormatException - if the table is not of a kind that can be handled by this handler

IOException - if an unexpected I/O error occurs during processing

docIncludesExample

public boolean docIncludesExample()

Description copied from interface: DocumentedIOHandler

Indicates whether the serialization of some (short) example table should be added to the user documentation for this handler. Binary formats, or instances for which the Documented.getXmlDescription() method already includes some example output, should return false.

Returns:

true if the user documentation would benefit from the addition of an example serialization

getXmlDescription

public String getXmlDescription()

Description copied from interface: Documented

Returns user-directed documentation in XML format.

The output should be a sequence of one or more <P> elements, using XHTML-like XML. Since rendering may be done in a number of contexts however, use of the full range of XHTML elements is discouraged. Where possible, the content should stick to simple markup such as the elements P, A, UL, OL, LI, DL, DT, DD EM, STRONG, I, B, CODE, TT, PRE.

Returns:

XML description of this object

setHasHeader

@ConfigMethod(property="header",
              doc="<p>Indicates whether the input CSV file contains the\noptional one-line header giving column names.\nOptions are:\n<ul>\n<li><code>true</code>: the first line is a header line containing column names</li>\n<li><code>false</code>: all lines are data lines, and column names will be assigned automatically</li>\n<li><code>null</code>: a guess will be made about whether the first line is a header or not depending on what it looks like</li>\n</ul>\nThe default value is <code>null</code> (auto-determination).\nThis usually works OK, but can get into trouble if\nall the columns look like string values.\n</p>",
              usage="true|false|null",
              example="true",
              sequence=1)
public void setHasHeader(Boolean hasHeader)

Sets whether input CSV files are known to include the optional header line or not.

Parameters:

hasHeader - true if input files are known to contain column names as the first line; false if they are known not to; null to auto-detect

getHasHeader

public Boolean getHasHeader()

Returns header interpretation policy.

Returns:

true if input files are known to contain column names as the first line; false if they are known not to; null to auto-detect

setDelimiter

@ConfigMethod(property="delimiter",
              doc="<p>Field delimiter character, by default a comma. Permitted values are a single character like \"<code>|</code>\", a hexadecimal character code like \"<code>0x7C</code>\", or one of the names \"<code>comma</code>\", \"<code>space</code>\" or \"<code>tab</code>\". Some choices of delimiter, for instance whitespace characters, might not work well or might behave in surprising ways.</p>",
              example="|",
              sequence=2)
public void setDelimiter(char delimiter)

Sets the delimiter character. Non-comma delimiters are not guaranteed to work.

Parameters:

delimiter - delimiter character

getDelimiter

public char getDelimiter()

Returns the delimiter character.

Returns:

delimiter