uk.ac.starlink.votable

Class VOTableWriter

java.lang.Object

uk.ac.starlink.votable.VOTableWriter

All Implemented Interfaces:

Documented, DocumentedIOHandler, MultiStarTableWriter, StarTableWriter

public class VOTableWriter
extends Object
implements StarTableWriter, MultiStarTableWriter, DocumentedIOHandler

Implementation of the StarTableWriter interface for VOTables. The dataFormat and inline attributes can be modified to affect how the bulk cell data are output - this may be in TABLEDATA, FITS, BINARY or BINARY2 format, and in the latter three cases may be either inline as base64 encoded CDATA or to a separate stream.

Some of the Auxiliary metadata items of the ColumnInfo metadata from written tables are respected:

• Tables.NULL_VALUE_INFO: sets the value of "magic" blank value for integer columns
• Tables.UBYTE_FLAG_INFO: if set to Boolean.TRUE and if the column has content class Short or short[], the data will be written with datatype="unsignedByte" instead of (signed 16-bit) "short".
• The COOSYS_*_INFO and TIMESYS_*_INFO items defined in the VOStarTable class; suitable COOSYS/TIMESYS elements will be written and referenced as required to honour these items.
• Various other of the *_INFO items defined in the VOStarTable class; this has the effect that VOTable column attributes read in from a VOTable will be passed through if the same table is written out to a VOTable (or VOTable-based format like FITS-plus).

Author:

Mark Taylor (Starlink)

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_XML_DECLARATION Default XML declaration in written documents.

Constructor Summary

Constructors

Constructor and Description
VOTableWriter() Constructs a default VOTableWriter.
VOTableWriter(DataFormat dataFormat, boolean inline) Constructs a VOTableWriter with specified output type and default VOTable version.
VOTableWriter(DataFormat dataFormat, boolean inline, VOTableVersion version) Constructs a VOTableWriter with specified output characterstics and a given version of the VOTable standard.

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.
DataFormat	getDataFormat() Returns the format in which this writer will output the bulk table data.
Charset	getEncoding() Returns the character encoding used for XML output.
String[]	getExtensions() Returns the list of filename extensions recognised by this handler.
String	getFormatName() Gives the name of the format which is written by this writer.
boolean	getInline() Indicates whether STREAM elements will be written inline or to an external file in the case of FITS and BINARY encoding.
String	getMimeType() Returns a string suitable for use as the value of a MIME Content-Type header.
VOTableVersion	getVotableVersion() Returns the version of the VOTable standard to which the output of this writer conforms.
boolean	getWriteDate() Indicates whether a datestamp is written to output VOTable files.
boolean	getWriteSchemaLocation() Indicates whether the schema location attribute will be written on opening VOTABLE tags.
String	getXMLDeclaration() Returns the XML declaration which is used by this writer at the head of any document written.
String	getXmlDescription() Returns user-directed documentation in XML format.
Boolean	isCompact() Returns whitespace formatting policy for TABLEDATA output.
boolean	looksLikeFile(String filename) Indicates whether the destination is of a familiar form for this kind of writer.
void	setCompact(Boolean compact) Controls whitespace formatting for TABLEDATA output, ignored for other formats.
void	setDataFormat(DataFormat format) Sets the format in which the table data will be output.
void	setEncoding(Charset encoding) Sets the XML encoding used for the output VOTable.
void	setInline(boolean inline) Sets whether STREAM elements should be written inline or to an external file in the case of FITS and BINARY encoding.
void	setVotableVersion(VOTableVersion version) Sets the version of the VOTable standard to which the output of this writer will conform.
void	setWriteDate(boolean writeDate) Configures whether a datestamp is written to output VOTable files.
void	setWriteSchemaLocation(boolean writeSchemaLocation) Determines whether the schema location attribute will be written on opening VOTABLE tags.
void	setXMLDeclaration(String xmlDecl) Sets the XML declaration which will be used by this writer at the head of any document written.
String	toString()
protected void	writeBetweenTableXML(BufferedWriter writer) Outputs text between one table (TABLE and possibly other associated elements) and the next.
void	writeInlineStarTable(StarTable startab, BufferedWriter writer) Writes a table directly to a stream.
void	writeInlineStarTables(StarTable[] startabs, BufferedWriter writer) Writes multiple tables directly to a stream.
protected void	writePostTableXML(BufferedWriter writer) Outputs all the text required after any tables in the output table document.
protected void	writePreTableXML(BufferedWriter writer) Outputs all the text required before any tables are written.
void	writeStarTable(StarTable startab, OutputStream out) Writes a StarTable to a given stream; must be inline.
void	writeStarTable(StarTable startab, OutputStream out, File file) Writes a StarTable to a given stream.
void	writeStarTable(StarTable startab, String location, StarTableOutput sto) Writes a StarTable to a given location.
void	writeStarTables(TableSequence tableSeq, OutputStream out) Writes a sequence of tables to a given stream; must be inline.
void	writeStarTables(TableSequence tableSeq, OutputStream out, File file) Writes a sequence of tables to a given stream.
void	writeStarTables(TableSequence tableSeq, String location, StarTableOutput sto) Writes a sequence of tables to a given location.

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.table.formats.DocumentedIOHandler

matchesExtension, readText, toLink

Field Detail

DEFAULT_XML_DECLARATION

public static final String DEFAULT_XML_DECLARATION

Default XML declaration in written documents.

See Also:

Constant Field Values

Constructor Detail

VOTableWriter

public VOTableWriter()

Constructs a default VOTableWriter. Output is in TABLEDATA format.

VOTableWriter

public VOTableWriter(DataFormat dataFormat,
                     boolean inline)

Constructs a VOTableWriter with specified output type and default VOTable version.

Parameters:

dataFormat - the format in which tables will be written

inline - whether output of streamed formats should be inline and base64-encoded or not

VOTableWriter

public VOTableWriter(DataFormat dataFormat,
                     boolean inline,
                     VOTableVersion version)

Constructs a VOTableWriter with specified output characterstics and a given version of the VOTable standard.

Parameters:

dataFormat - the format in which tables will be written

inline - whether output of streamed formats should be inline and base64-encoded or not

version - version of the VOTable standard

Method Detail

writeStarTable

public void writeStarTable(StarTable startab,
                           String location,
                           StarTableOutput sto)
                    throws IOException

Writes a StarTable to a given location.

Specified by:

writeStarTable in interface StarTableWriter

Parameters:

startab - the table to write

location - the filename to which to write the table

sto - object used for location resolution

Throws:

TableFormatException - if startab cannot be written to location

IOException - if there is some I/O error

writeStarTables

public void writeStarTables(TableSequence tableSeq,
                            String location,
                            StarTableOutput sto)
                     throws IOException

Writes a sequence of tables to a given location. They are written as separate TABLE elements in the same VOTable document.

Specified by:

writeStarTables in interface MultiStarTableWriter

Parameters:

tableSeq - table sequence

location - the filename to which to write the table

sto - object used for location resolution

Throws:

IOException

writeStarTable

public void writeStarTable(StarTable startab,
                           OutputStream out)
                    throws IOException

Writes a StarTable to a given stream; must be inline. Same as writeStarTable(startab,out,(File)null).

Specified by:

writeStarTable in interface StarTableWriter

Parameters:

startab - the table to write

out - the stream down which to write the table

Throws:

TableFormatException - if this table cannot be written to a stream

IOException - if there is some I/O error

writeStarTables

public void writeStarTables(TableSequence tableSeq,
                            OutputStream out)
                     throws IOException

Writes a sequence of tables to a given stream; must be inline. Same as writeStarTables(tableSeq,out,null).

Specified by:

writeStarTables in interface MultiStarTableWriter

Parameters:

tableSeq - tables to write

out - destination stream

Throws:

IOException

writeStarTable

public void writeStarTable(StarTable startab,
                           OutputStream out,
                           File file)
                    throws IOException

Writes a StarTable to a given stream.

Parameters:

startab - the table to write

out - the stream down which to write the table

file - the filename to which out refers; this is used if necessary to come up with a suitable filename for related files which need to be written. May be null.

Throws:

IOException

writeStarTables

public void writeStarTables(TableSequence tableSeq,
                            OutputStream out,
                            File file)
                     throws IOException

Writes a sequence of tables to a given stream.

Parameters:

tableSeq - table sequence to write

out - destination stream

file - the filename to which out refers; this is used if necessary to come up with a suitable filename for related files which need to be written. May be null.

Throws:

IOException

writeInlineStarTable

public void writeInlineStarTable(StarTable startab,
                                 BufferedWriter writer)
                          throws IOException

Writes a table directly to a stream.

Parameters:

startab - table to write

writer - destination stream

Throws:

IOException

writeInlineStarTables

public void writeInlineStarTables(StarTable[] startabs,
                                  BufferedWriter writer)
                           throws IOException

Writes multiple tables directly to a stream.

Parameters:

startabs - tables

writer - destination stream

Throws:

IOException

writePreTableXML

protected void writePreTableXML(BufferedWriter writer)
                         throws IOException

Outputs all the text required before any tables are written. This method can be overridden to alter the behaviour of the writer if required.

Parameters:

writer - destination stream

Throws:

IOException

See Also:

writePostTableXML(java.io.BufferedWriter)

writeBetweenTableXML

protected void writeBetweenTableXML(BufferedWriter writer)
                             throws IOException

Outputs text between one table (TABLE and possibly other associated elements) and the next. It's only called as a separator between adjacent tables, not at the start or end of a sequence of them; hence it's not called if only a single table is being output. This method can be overridden to alter the behaviour of the writer if required.

This method closes one RESOURCE element and opens another one.

Parameters:

writer - destination stream

Throws:

IOException

writePostTableXML

protected void writePostTableXML(BufferedWriter writer)
                          throws IOException

Outputs all the text required after any tables in the output table document. This method can be overridden to alter the behaviour of this writer if required.

Parameters:

writer - destination stream

Throws:

IOException

See Also:

writePreTableXML(java.io.BufferedWriter)

getExtensions

public String[] getExtensions()

Description copied from interface: DocumentedIOHandler

Returns the list of filename extensions recognised by this handler.

Specified by:

getExtensions in interface DocumentedIOHandler

Returns:

lower-cased filename extension strings, no "." characters

looksLikeFile

public boolean looksLikeFile(String filename)

Description copied from interface: StarTableWriter

Indicates whether the destination is of a familiar form for this kind of writer. This may be used to guess what kind of format a table should be written in. Implementations should return true for values of location which look like the normal form for their output format, for instance one with the usual file extension.

Specified by:

looksLikeFile in interface StarTableWriter

Parameters:

filename - the location name (probably filename)

Returns:

true iff it looks like a file this writer would normally write

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.

Specified by:

docIncludesExample in interface DocumentedIOHandler

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.

Specified by:

getXmlDescription in interface Documented

Returns:

XML description of this object

getFormatName

public String getFormatName()

Description copied from interface: StarTableWriter

Gives the name of the format which is written by this writer. Matching against this string may be used by callers to identify or select this writer from a list.

Specified by:

getFormatName in interface StarTableWriter

Returns:

a short string identifying the output format of this writer

getMimeType

public String getMimeType()

Description copied from interface: StarTableWriter

Returns a string suitable for use as the value of a MIME Content-Type header. If no suitable MIME type is available or known, one of "application/octet-stream" (for binary formats) or "text/plain" for ASCII ones) is recommended.

Specified by:

getMimeType in interface StarTableWriter

Returns:

MIME content type

setDataFormat

@ConfigMethod(property="format",
              usage="TABLEDATA|BINARY|BINARY2|FITS",
              doc="<p>Gives the serialization type (DATA element content) of output VOTables.</p>",
              example="BINARY2",
              sequence=1)
public void setDataFormat(DataFormat format)

Sets the format in which the table data will be output.

Parameters:

format - bulk data format

getDataFormat

public DataFormat getDataFormat()

Returns the format in which this writer will output the bulk table data.

Returns:

bulk data format

setInline

@ConfigMethod(property="inline",
              doc="If true, STREAM elements are written base64-encoded within the body of the document, and if false they are written to a new external binary file whose name is derived from that of the output VOTable document. This is only applicable to BINARY, BINARY2 and FITS formats where output is not to a stream.",
              sequence=3)
public void setInline(boolean inline)

Sets whether STREAM elements should be written inline or to an external file in the case of FITS and BINARY encoding.

Parameters:

inline - true iff streamed data will be encoded inline in the STREAM element

getInline

public boolean getInline()

Indicates whether STREAM elements will be written inline or to an external file in the case of FITS and BINARY encoding.

Returns:

true iff streamed data will be encoded inline in the STREAM element

setXMLDeclaration

public void setXMLDeclaration(String xmlDecl)

Sets the XML declaration which will be used by this writer at the head of any document written. By default this is the value of DEFAULT_XML_DECLARATION.

Parameters:

xmlDecl - new XML declaration

getXMLDeclaration

public String getXMLDeclaration()

Returns the XML declaration which is used by this writer at the head of any document written.

Returns:

XML declaration

setVotableVersion

@ConfigMethod(property="version",
              usage="V10|V11|V12|V13|V14|V15",
              example="V13",
              doc="<p>Gives the version of the VOTable format which will be used when writing the VOTable.\n\"<code>V10</code>\" is version 1.0 etc.</p>",
              sequence=2)
public void setVotableVersion(VOTableVersion version)

Sets the version of the VOTable standard to which the output of this writer will conform.

Parameters:

version - new version

getVotableVersion

public VOTableVersion getVotableVersion()

Returns the version of the VOTable standard to which the output of this writer conforms.

Returns:

version

setCompact

@ConfigMethod(property="compact",
              example="true",
              doc="<p>Controls whitespace formatting for TABLEDATA output,\nignored for other formats.\nBy default a decision will be taken dependent on table width.\n</p>",
              sequence=4)
public void setCompact(Boolean compact)

Controls whitespace formatting for TABLEDATA output, ignored for other formats. If null (the default), a decision will be taken dependent on table width.

Parameters:

compact - TRUE for compact TABLEDATA output, FALSE for more whitespace, null for auto

isCompact

public Boolean isCompact()

Returns whitespace formatting policy for TABLEDATA output.

Returns:

TRUE for compact TABLEDATA output, FALSE for more whitespace, null for auto

setEncoding

@ConfigMethod(property="encoding",
              usage="UTF-8|UTF-16|...",
              example="UTF-16",
              doc="<p>Specifies the XML encoding used in the output VOTable.\nThe default value is UTF-8.\nNote that certain optimisations are in place for UTF-8 output\nwhich means that other encodings may be significantly slower.\n</p>",
              sequence=5)
public void setEncoding(Charset encoding)

Sets the XML encoding used for the output VOTable. The default value is UTF-8. Note that certain optimisations are in place for UTF-8 output which means that other encodings may be significantly slower.

Parameters:

encoding - encoding charset

getEncoding

public Charset getEncoding()

Returns the character encoding used for XML output.

Returns:

encoding charset

setWriteDate

@ConfigMethod(property="date",
              doc="<p>If true, the output file will contain a comment recording the current date; otherwise it is not included.</p>")
public void setWriteDate(boolean writeDate)

Configures whether a datestamp is written to output VOTable files.

Parameters:

writeDate - true to include a date in the XML comments, false to omit it

getWriteDate

public boolean getWriteDate()

Indicates whether a datestamp is written to output VOTable files.

Returns:

true if a date is included in the XML comments, false if not

setWriteSchemaLocation

public void setWriteSchemaLocation(boolean writeSchemaLocation)

Determines whether the schema location attribute will be written on opening VOTABLE tags.

Parameters:

writeSchemaLocation - whether to write xsi:schemaLocation atts

getWriteSchemaLocation

public boolean getWriteSchemaLocation()

Indicates whether the schema location attribute will be written on opening VOTABLE tags.

Returns:

whether xsi:schemaLocation attributes will be written

toString

public String toString()

Overrides:

toString in class Object