tap.data

Class VOTableIterator

java.lang.Object

tap.data.VOTableIterator

All Implemented Interfaces:

TableIterator

public class VOTableIterator
extends java.lang.Object
implements TableIterator

TableIterator which lets iterate over a VOTable input stream using STIL.

getColType() will return TAP type based on the type declared in the VOTable metadata part.

Since:

2.0

Version:

2.1 (03/2017)

Author:

Grégory Mantelet (ARI)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	VOTableIterator.StreamVOTableSink This class lets consume the metadata and rows of a VOTable document.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	endReached Indicate whether the last row has already been reached.
protected int	indCol Index of the last read column (=0 just after nextRow() and before nextCol(), =nbCol after the last column has been read).
protected java.io.InputStream	input Stream containing the VOTable on which this TableIterator is iterating.
protected boolean	iterationStarted Indicate whether the row iteration has already started.
protected int	nbCol Number of columns available according to the metadata.
protected java.lang.Object[]	row The last read row.
protected VOTableIterator.StreamVOTableSink	sink The StarTable consumer which is used to iterate on each row.
protected static java.lang.String	STREAM_ABORTED_MESSAGE Message of the IOException sent when the streaming is aborted.

Constructor Summary

Constructors

Constructor and Description
VOTableIterator(java.io.InputStream input) Build a TableIterator able to read rows and columns inside the given VOTable input stream.

Method Summary

Modifier and Type	Method and Description
protected void	checkReadState() Check the row iteration state.
void	close() Close the stream or input over which this class iterates.
DBType	getColType() Get the type of the current column value.
TAPColumn[]	getMetadata() Get all the metadata column that have been successfully extracted at the creation of this iterator.
boolean	hasNextCol() Tell whether another column is available.
java.lang.Object	nextCol() Return the value of the next column.
boolean	nextRow() Go to the next row if there is one.
static VotType	resolveVotType(java.lang.String datatype, java.lang.String arraysize, java.lang.String xtype) Resolve a VOTable field type by using the datatype, arraysize and xtype strings as specified in a VOTable document.

Methods inherited from class java.lang.Object

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

Field Detail

STREAM_ABORTED_MESSAGE

protected static final java.lang.String STREAM_ABORTED_MESSAGE

Message of the IOException sent when the streaming is aborted.

See Also:

Constant Field Values

input

protected final java.io.InputStream input

Stream containing the VOTable on which this TableIterator is iterating.

sink

protected final VOTableIterator.StreamVOTableSink sink

The StarTable consumer which is used to iterate on each row.

iterationStarted

protected boolean iterationStarted

Indicate whether the row iteration has already started.

endReached

protected boolean endReached

Indicate whether the last row has already been reached.

row

protected java.lang.Object[] row

The last read row. Column iteration is done on this array.

indCol

protected int indCol

Index of the last read column (=0 just after nextRow() and before nextCol(), =nbCol after the last column has been read).

nbCol

protected int nbCol

Number of columns available according to the metadata.

Constructor Detail

VOTableIterator

public VOTableIterator(java.io.InputStream input)
                throws DataReadException

Build a TableIterator able to read rows and columns inside the given VOTable input stream.

Parameters:

input - Input stream over a VOTable document.

Throws:

java.lang.NullPointerException - If NULL is given in parameter.

DataReadException - If the given VOTable can not be parsed.

Method Detail

getMetadata

public TAPColumn[] getMetadata()
                        throws DataReadException

Description copied from interface: TableIterator

Get all the metadata column that have been successfully extracted at the creation of this iterator.

Important: This function should be callable at any moment from the creation of the iterator until the end of the table dataset has been reached.

Note: This function MAY BE NOT IMPLEMENTED or the metadata can not be fetched. In this case, NULL will be returned.

Warning: If the metadata part of the original document is corrupted (i.e. false number of columns), the column type information should be fetched thanks to TableIterator.getColType() while iterating over rows and columns.

Specified by:

getMetadata in interface TableIterator

Returns:

An array of TAPColumn objects (each for a column of any row), or NULL if this function is not implemented OR if it was not possible to get these metadata.

Throws:

DataReadException

See Also:

TableIterator.getColType()

nextRow

public boolean nextRow()
                throws DataReadException

Description copied from interface: TableIterator

Go to the next row if there is one.

Note: After a call to this function the columns must be fetched individually using TableIterator.nextCol() IF this function returned true.

Specified by:

nextRow in interface TableIterator

Returns:

true if the next row has been successfully reached, false if no more rows can be read.

Throws:

DataReadException - If an error occurs while reading the table dataset.

hasNextCol

public boolean hasNextCol()
                   throws java.lang.IllegalStateException,
                          DataReadException

Description copied from interface: TableIterator

Tell whether another column is available.

Specified by:

hasNextCol in interface TableIterator

Returns:

true if TableIterator.nextCol() will return the value of the next column with no error, false otherwise.

Throws:

java.lang.IllegalStateException - If TableIterator.nextRow() has not yet been called.

DataReadException - If an error occurs while reading the table dataset.

nextCol

public java.lang.Object nextCol()
                         throws java.util.NoSuchElementException,
                                java.lang.IllegalStateException,
                                DataReadException

Description copied from interface: TableIterator

Return the value of the next column.

Note: The column type can be fetched using TableIterator.getColType() after a call to TableIterator.nextCol().

Specified by:

nextCol in interface TableIterator

Returns:

Get the value of the next column.

Throws:

java.util.NoSuchElementException - If no more column value is available.

java.lang.IllegalStateException - If TableIterator.nextRow() has not yet been called.

DataReadException - If an error occurs while reading the table dataset.

getColType

public DBType getColType()
                  throws java.lang.IllegalStateException,
                         DataReadException

Description copied from interface: TableIterator

Get the type of the current column value.

Note 1: "Current column value" means here "the value last returned by TableIterator.nextCol()".

Note 2: This function MAY BE NOT IMPLEMENTED or the type information can not be fetched. If this is the case, NULL will be returned.

Warning: In some cases, the metadata part of the original document does not match with the data it should have represented. In such case, the types returned here and by TableIterator.getMetadata() would be different. In case of such mismatch, the type returned by TableIterator.getColType() should be considered as more correct/accurate.

Specified by:

getColType in interface TableIterator

Returns:

Type of the current column value, or NULL if this information is not available or if this function is not implemented.

Throws:

java.lang.IllegalStateException - If TableIterator.nextCol() has not yet been called.

DataReadException - If an error occurs while reading the table dataset.

close

public void close()
           throws DataReadException

Description copied from interface: TableIterator

Close the stream or input over which this class iterates.

Specified by:

close in interface TableIterator

Throws:

DataReadException - If any error occurs while closing it.

checkReadState

protected void checkReadState()
                       throws java.lang.IllegalStateException

Check the row iteration state. That's to say whether:

• the row iteration has started = the first row has been read = a first call of nextRow() has been done
• AND the row iteration is not finished = the last row has been read.

Throws:

java.lang.IllegalStateException

resolveVotType

public static VotType resolveVotType(java.lang.String datatype,
                                     java.lang.String arraysize,
                                     java.lang.String xtype)
                              throws DataReadException

Resolve a VOTable field type by using the datatype, arraysize and xtype strings as specified in a VOTable document.

Parameters:

datatype - Attribute value of VOTable corresponding to the datatype.

arraysize - Attribute value of VOTable corresponding to the arraysize.

xtype - Attribute value of VOTable corresponding to the xtype.

Returns:

The resolved VOTable field type.

Throws:

DataReadException - If a field datatype is unknown or missing.