uk.ac.starlink.cdf

Class CdfStarTable

java.lang.Object

uk.ac.starlink.table.AbstractStarTable

uk.ac.starlink.cdf.CdfStarTable

All Implemented Interfaces:

Closeable, AutoCloseable, StarTable

public class CdfStarTable
extends AbstractStarTable

StarTable implementation for CDF files.

Since:

24 Jun 2013

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
CdfStarTable(uk.ac.bristol.star.cdf.CdfContent content, CdfTableProfile profile, uk.ac.bristol.star.cdf.Variable dependVar) Constructor.

Method Summary

Modifier and Type	Method and Description
Object	getCell(long irow, int icol) The AbstractStarTable implementation of this method throws an UnsupportedOperationException, since unless otherwise provided there is no random access.
int	getColumnCount() Returns the number of columns in this table.
ColumnInfo	getColumnInfo(int icol) Returns the object describing the data in a given column.
RowAccess	getRowAccess() Returns an object which can provide random access to this table's data, if random access is implemented.
long	getRowCount() Returns the number of rows in this table, if known.
RowSequence	getRowSequence() Returns an object which can iterate over all the rows in the table sequentially.
static String	getStringEntry(uk.ac.bristol.star.cdf.VariableAttribute att, uk.ac.bristol.star.cdf.Variable var) Gets a variable's attribute value expected to be of string type.
boolean	isRandom() The AbstractStarTable implementation of this method returns false.

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

checkedLongToInt, close, getColumnAuxDataInfos, getName, getParameters, getRow, getRowSplittable, getURL, 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

CdfStarTable

public CdfStarTable(uk.ac.bristol.star.cdf.CdfContent content,
                    CdfTableProfile profile,
                    uk.ac.bristol.star.cdf.Variable dependVar)
             throws IOException

Constructor.

The optional dependVar parameter provides an effective grouping of columns, and corresponds to the DEPEND_0 variable attribute defined by the ISTP Metadata Guidelines. CDF files contain multiple variables that are not necessarily all columns of the same table; at least within the ISTP guidelines a table is effectively defined by an independent epoch variable and a number of other variables depending on that (and thus presumably having the same number of values/rows). This interpretation is not exactly explicit in ISTP, but it looks like our best bet for turning CDF content into a thing or things that look like StarTables. If dependVar is null, we just have to assume that all the variables are effectively columns in the same table. In case that they don't all have the same multiplicity, just guess something and issue a warning.

Parameters:

content - CDF data content object

profile - parameterisation of how CDFs should get turned into StarTables

dependVar - independent variable on which other columns depend, or null

Throws:

IOException - in case of error

Method Detail

getColumnCount

public int getColumnCount()

Description copied from interface: StarTable

Returns the number of columns in this table.

Specified by:

getColumnCount in interface StarTable

Specified by:

getColumnCount in class AbstractStarTable

Returns:

the number of columns

getRowCount

public long getRowCount()

Description copied from interface: StarTable

Returns the number of rows in this table, if known. If the number of rows cannot be (easily) determined, a value of -1 will be returned.

Specified by:

getRowCount in interface StarTable

Specified by:

getRowCount in class AbstractStarTable

Returns:

the number of rows, or -1

getColumnInfo

public ColumnInfo getColumnInfo(int icol)

Description copied from interface: StarTable

Returns the object describing the data in a given column.

Specified by:

getColumnInfo in interface StarTable

Specified by:

getColumnInfo in class AbstractStarTable

Parameters:

icol - the column for which header information is required

Returns:

a ValueInfo object for column icol

isRandom

public boolean isRandom()

Description copied from class: AbstractStarTable

The AbstractStarTable implementation of this method returns false.

Specified by:

isRandom in interface StarTable

Overrides:

isRandom in class AbstractStarTable

Returns:

true if table random access methods are available

getCell

public Object getCell(long irow,
                      int icol)
               throws IOException

Description copied from class: AbstractStarTable

The AbstractStarTable implementation of this method throws an UnsupportedOperationException, since unless otherwise provided there is no random access.

Specified by:

getCell in interface StarTable

Overrides:

getCell in class AbstractStarTable

Parameters:

irow - the index of the cell's row

icol - the index of the cell's column

Returns:

the contents of this cell

Throws:

IOException - if there is an error reading the data

getRowSequence

public RowSequence getRowSequence()
                           throws IOException

Description copied from interface: StarTable

Returns an object which can iterate over all the rows in the table sequentially. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.

Specified by:

getRowSequence in interface StarTable

Specified by:

getRowSequence in class AbstractStarTable

Returns:

new RowSequence

Throws:

IOException - if there is an error providing access

getRowAccess

public RowAccess getRowAccess()
                       throws IOException

Description copied from interface: StarTable

Returns an object which can provide random access to this table's data, if random access is implemented. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.

Specified by:

getRowAccess in interface StarTable

Overrides:

getRowAccess in class AbstractStarTable

Returns:

new RowAccess

Throws:

IOException - if there is an error setting up access

getStringEntry

public static String getStringEntry(uk.ac.bristol.star.cdf.VariableAttribute att,
                                    uk.ac.bristol.star.cdf.Variable var)

Gets a variable's attribute value expected to be of string type.

Parameters:

att - attribute

var - variable

Returns:

string value of att for var, or null if it doesn't exist or has the wrong type