ColumnDataSpec (Starjava TTOOLS API)

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 Description

ColumnDataSpec(uk.ac.starlink.table.StarTable table, Coord[] coords, int[][] userCoordColIndices)
Constructor.

Constructors
Constructor	Description
`ColumnDataSpec(uk.ac.starlink.table.StarTable table, Coord[] coords, int[][] userCoordColIndices)`	Constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	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.
`java.lang.Object`	`getCoordId(int ic)`	Returns an identifier for one of the the columns produced by this object.
`java.lang.Object`	`getMaskId()`	Returns an identifier for the row mask for this object.
`uk.ac.starlink.table.StarTable`	`getSourceTable()`	Returns the table object from which this data spec's data is obtained.
`uk.ac.starlink.table.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.
`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.

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(uk.ac.starlink.table.StarTable table,
                      Coord[] coords,
                      int[][] userCoordColIndices)
```
    Constructor.
    
    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
- Method Detail
  - getSourceTable
```
public uk.ac.starlink.table.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 java.lang.Object getCoordId(int ic)
```
    Description copied from interface: DataSpec
    
    Returns an identifier for one of the the columns produced by this object.
    
    Parameters:
    
    ic - column index
    
    Returns:
    
    column identifier, should implement equals sensibly
  - 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 java.lang.Object getMaskId()
```
    Description copied from interface: DataSpec
    
    Returns an identifier for the row mask for this object.
    
    Returns:
    
    mask identifier, should implement equals sensibly
  - getUserCoordInfos
```
public uk.ac.starlink.table.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; elements may be null if not known
  - 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
  - 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

Class ColumnDataSpec

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

ColumnDataSpec

Method Detail

getSourceTable

getCoordCount

getCoordId

getCoord

getMaskId

getUserCoordInfos

createUserDataReader

isCoordBlank