uk.ac.starlink.vo

Class TableSetSaxHandler

java.lang.Object

org.xml.sax.helpers.DefaultHandler

uk.ac.starlink.vo.TableSetSaxHandler

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

public class TableSetSaxHandler
extends DefaultHandler

Parses an XML document which describes Tabular Data as prescribed by the VODataService standard. It will pick up <table> elements (of type vs:Table), or elements that look like them, to build a picture of the tables and their columns and foreign keys. XML documents of this type are exposed by VOSI and TAP services.

The easiest way to make use of this class is via the static method readTableSet(java.net.URL, uk.ac.starlink.util.ContentCoding) or the convenience main(java.lang.String[]) method.

See Also:

IVOA VODataService Recommendation

Constructor Summary

Constructors

Constructor and Description
TableSetSaxHandler() Constructor.

Method Summary

Modifier and Type	Method and Description
void	characters(char[] ch, int start, int length)
void	endDocument()
void	endElement(String uri, String localName, String qName)
void	endPrefixMapping(String prefix)
TableMeta[]	getNakedTables() Returns the array of table metadata objects which were found outside of any schema.
SchemaMeta[]	getSchemas(boolean includeNaked) Returns the array of schema metadata objects which have been read by this parser.
void	ignorableWhitespace(char[] ch, int start, int length)
static void	main(String[] args) Main method to parse a tableset from the command line.
static TableSetSaxHandler	populateHandler(URL url, ContentCoding coding) Uses an instance of this class to parse the document at a given URL.
void	processingInstruction(String target, String data)
static TableMeta[]	readTables(URL url, ContentCoding coding) Uses an instance of this class to read an XML document from a given URL and extracts a flat list of all the TableMeta objects it represents.
static SchemaMeta[]	readTableSet(URL url, ContentCoding coding) Uses an instance of this class to read an XML document from a given URL and extract the SchemaMeta objects it represents.
void	setDocumentLocator(Locator locator)
void	skippedEntity(String name)
void	startDocument()
void	startElement(String uri, String localName, String qName, Attributes atts)
void	startPrefixMapping(String prefix, String uri)

Methods inherited from class org.xml.sax.helpers.DefaultHandler

error, fatalError, notationDecl, resolveEntity, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

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

Constructor Detail

TableSetSaxHandler

public TableSetSaxHandler()

Constructor.

Method Detail

getSchemas

public SchemaMeta[] getSchemas(boolean includeNaked)

Returns the array of schema metadata objects which have been read by this parser. Only non-empty following a parse.

Parameters:

includeNaked - if false, only the schemas actually encountered are returned; if true, then any naked tables will be included in a dummy schema in the result

Returns:

fully populated table metadata

getNakedTables

public TableMeta[] getNakedTables()

Returns the array of table metadata objects which were found outside of any schema. Only non-empty following a parse.

Returns:

table metadata

startDocument

public void startDocument()

Specified by:

startDocument in interface ContentHandler

Overrides:

startDocument in class DefaultHandler

endDocument

public void endDocument()

Specified by:

endDocument in interface ContentHandler

Overrides:

endDocument in class DefaultHandler

startElement

public void startElement(String uri,
                         String localName,
                         String qName,
                         Attributes atts)

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class DefaultHandler

endElement

public void endElement(String uri,
                       String localName,
                       String qName)

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class DefaultHandler

characters

public void characters(char[] ch,
                       int start,
                       int length)

Specified by:

characters in interface ContentHandler

Overrides:

characters in class DefaultHandler

ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)

Specified by:

ignorableWhitespace in interface ContentHandler

Overrides:

ignorableWhitespace in class DefaultHandler

startPrefixMapping

public void startPrefixMapping(String prefix,
                               String uri)

Specified by:

startPrefixMapping in interface ContentHandler

Overrides:

startPrefixMapping in class DefaultHandler

endPrefixMapping

public void endPrefixMapping(String prefix)

Specified by:

endPrefixMapping in interface ContentHandler

Overrides:

endPrefixMapping in class DefaultHandler

processingInstruction

public void processingInstruction(String target,
                                  String data)

Specified by:

processingInstruction in interface ContentHandler

Overrides:

processingInstruction in class DefaultHandler

skippedEntity

public void skippedEntity(String name)

Specified by:

skippedEntity in interface ContentHandler

Overrides:

skippedEntity in class DefaultHandler

setDocumentLocator

public void setDocumentLocator(Locator locator)

Specified by:

setDocumentLocator in interface ContentHandler

Overrides:

setDocumentLocator in class DefaultHandler

readTableSet

public static SchemaMeta[] readTableSet(URL url,
                                        ContentCoding coding)
                                 throws IOException,
                                        SAXException

Uses an instance of this class to read an XML document from a given URL and extract the SchemaMeta objects it represents.

Parameters:

url - containing a TableSet document or similar

coding - configures HTTP content-coding

Returns:

array of schema metadata objects giving table metadata

Throws:

IOException

SAXException

readTables

public static TableMeta[] readTables(URL url,
                                     ContentCoding coding)
                              throws IOException,
                                     SAXException

Uses an instance of this class to read an XML document from a given URL and extracts a flat list of all the TableMeta objects it represents. This includes all the tables in schemas, as well as any outside any <schema> element.

Parameters:

url - containing a TableSet document or similar

coding - configures HTTP content-coding

Returns:

flat list of all tables

Throws:

IOException

SAXException

populateHandler

public static TableSetSaxHandler populateHandler(URL url,
                                                 ContentCoding coding)
                                          throws IOException,
                                                 SAXException

Uses an instance of this class to parse the document at a given URL.

Parameters:

url - containing a TableSet document or similar

coding - configures HTTP content-coding

Returns:

handler containing located items

Throws:

IOException

SAXException

main

public static void main(String[] args)
                 throws IOException,
                        SAXException

Main method to parse a tableset from the command line.

Parameters:

args - first element is a URL to read from

Throws:

IOException

SAXException