uk.ac.starlink.ttools.plot2.task

Class ColumnDataSpec

java.lang.Object

uk.ac.starlink.ttools.plot2.data.AbstractDataSpec

uk.ac.starlink.ttools.plot2.task.ColumnDataSpec

All Implemented Interfaces:

DataSpec

public class ColumnDataSpec
extends AbstractDataSpec

DataSpec implementation that simply selects columns by index from an input table. The mask is taken to be always true.

Since:

25 Sep 2013

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
ColumnDataSpec(StarTable table, Coord[] coords, int[][] userCoordColIndices) Constructs a ColumnDataSpec with default mappers.
ColumnDataSpec(StarTable table, Coord[] coords, int[][] userCoordColIndices, DomainMapper[][] userCoordMappers) Constructs a ColumnDataSpec with supplied mappers.

Method Summary

Modifier and Type	Method and Description
UserDataReader	createUserDataReader() Returns an object that can be used to read the mask and coordinate values from a row sequence derived from this object's source table.
Coord	getCoord(int ic) Returns the coord reader that can read the data for one of this object's output columns.
int	getCoordCount() Returns the number of columns that this object produces.
String	getCoordId(int ic) Returns an identifier for one of the the columns produced by this object.
String	getMaskId() Returns an identifier for the row mask for this object.
StarTable	getSourceTable() Returns the table object from which this data spec's data is obtained.
ValueInfo[]	getUserCoordInfos(int ic) Returns the metadata, if known, for the values supplied by the user to provide data for one of this object's output columns.
DomainMapper[]	getUserCoordMappers(int ic) Returns the domain mappers to use for the values supplied by the user to provide data for one of this object's output columns.
boolean	isCoordBlank(int icoord) Indicates whether the value for a given coord specified by this object is known to have a constant, blank value in all cases.
boolean	isMaskTrue() Returns true.

Methods inherited from class uk.ac.starlink.ttools.plot2.data.AbstractDataSpec

equals, hashCode

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnDataSpec

public ColumnDataSpec(StarTable table,
                      Coord[] coords,
                      int[][] userCoordColIndices)

Constructs a ColumnDataSpec with default mappers.

Parameters:

table - input table

coords - coordinate definitions for which columns are required

userCoordColIndices - nCoord-element array, each element an array of column indices for the table columns containing user values for the corresponding Coord

ColumnDataSpec

public ColumnDataSpec(StarTable table,
                      Coord[] coords,
                      int[][] userCoordColIndices,
                      DomainMapper[][] userCoordMappers)

Constructs a ColumnDataSpec with supplied mappers.

Parameters:

table - input table

coords - coordinate definitions for which columns are required

userCoordColIndices - nCoord-element array, each element an array of column indices for the table columns containing user values for the corresponding Coord

userCoordMappers - nCoord-element array, each element an array of domain mappers for the table columns containing domain mappers for the corresponding Coord

Method Detail

getSourceTable

public StarTable getSourceTable()

Description copied from interface: DataSpec

Returns the table object from which this data spec's data is obtained.

Returns:

data source table

getCoordCount

public int getCoordCount()

Description copied from interface: DataSpec

Returns the number of columns that this object produces.

Returns:

TupleSequence column count

getCoordId

public String getCoordId(int ic)

Description copied from interface: DataSpec

Returns an identifier for one of the the columns produced by this object. Coords with the same identifier must mean the same thing, and preferably vice versa.

Parameters:

ic - column index

Returns:

column identifier

getCoord

public Coord getCoord(int ic)

Description copied from interface: DataSpec

Returns the coord reader that can read the data for one of this object's output columns.

Parameters:

ic - column index

Returns:

column data reader

getMaskId

public String getMaskId()

Description copied from interface: DataSpec

Returns an identifier for the row mask for this object. Masks with the same identifier must mean the same thing, and preferably vice versa.

Returns:

mask identifier

getUserCoordInfos

public ValueInfo[] getUserCoordInfos(int ic)

Description copied from interface: DataSpec

Returns the metadata, if known, for the values supplied by the user to provide data for one of this object's output columns.

Parameters:

ic - column index

Returns:

array of value infos for column data inputs; elements may be null if not known

getUserCoordMappers

public DomainMapper[] getUserCoordMappers(int ic)

Description copied from interface: DataSpec

Returns the domain mappers to use for the values supplied by the user to provide data for one of this object's output columns. These objects define how the input values as supplied by the user are to be interpreted as the expected input values for this dataspec. In many cases this mapping is trivial (for instance Y axis coordinate), but in some (for instance absolute epoch) it may not be.

Parameters:

ic - column index

Returns:

array of DomainMappers for column data inputs

createUserDataReader

public UserDataReader createUserDataReader()

Description copied from interface: DataSpec

Returns an object that can be used to read the mask and coordinate values from a row sequence derived from this object's source table. A given UserDataReader can only be used from a single thread, but multiple returns from this method may be used concurrently in different threads.

Returns:

new data reader

isMaskTrue

public boolean isMaskTrue()

Returns true.

Returns:

true if all rows are known to be included in the mask

isCoordBlank

public boolean isCoordBlank(int icoord)

Description copied from interface: DataSpec

Indicates whether the value for a given coord specified by this object is known to have a constant, blank value in all cases. Clients don't have to test this, since data stores will always dispense the relevant blank value based on this data spec, and should do so in an efficient manner, but it may be useful for clients to know in advance that a column is blank all the way down. False negatives are permitted: even if the result is false, the column may in fact have all blank values.

Parameters:

icoord - column index

Returns:

true if all values in the column are always blank