uk.ac.starlink.ttools.plot2.data

Interface Tuple

All Known Subinterfaces:

TupleSequence

All Known Implementing Classes:

AbortTupleSequence, CachedTupleSequence, WrapperTuple

public interface Tuple

Defines a tuple of typed values for plotting. Such tuples are implicitly part of a sequence, that is they represent a row in a table. Elements of the tuple may be referred to as fields or columns, and are accessed by field/column index.

Different typed access methods are provided for retrieving the result of each column. It is up to the caller to keep track of which is the right one to use. It's done this way so that we can return primitive values.

Note that in most cases a Tuple instance is also a TupleSequence. That means that once the TupleSequence has been advanced to the next row, calling the Tuple methods will give different values. It follows that calls to a Tuple instance should be made and the results consumed synchronously before the next iteration, such instances are generally not suitable for hanging on to outside of an iteration step.

The point of separating the two interfaces is to make it clear when a client is only permitted to read the values and not to advance the iterator.

Since:

25 Apr 2017

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
boolean	getBooleanValue(int icol) Returns the value of a given column as a boolean.
double	getDoubleValue(int icol) Returns the value of a given column as a double.
int	getIntValue(int icol) Returns the value of a given column as an integer.
long	getLongValue(int icol) Returns the value of a given column as a long.
Object	getObjectValue(int icol) Returns the value of a given column as an object.
long	getRowIndex() Returns the row index for the underlying data set.

Method Detail

getRowIndex

long getRowIndex()

Returns the row index for the underlying data set. Note this value may not undergo a simple increment between steps (if rows are excluded from the underlying data set it may increase by more than one in some cases).

Returns:

row index of underlying table row

getObjectValue

Object getObjectValue(int icol)

Returns the value of a given column as an object. If that element of the tuple is not of object type, the result may not be useful.

If the result is a mutable object, its value may be overwritten by subsequent calls to this method (especially following calls to TupleSequence.next() if this object also implements TupleSequence).

Parameters:

icol - column index

Returns:

value of element icol, presumed of object type

getDoubleValue

double getDoubleValue(int icol)

Returns the value of a given column as a double. If that element of the tuple is not of numeric type, the result may not be useful.

Parameters:

icol - column index

Returns:

value of element icol, presumed of numeric type

getIntValue

int getIntValue(int icol)

Returns the value of a given column as an integer. If that element of the tuple is not of numeric type, the result may not be useful.

Parameters:

icol - column index

Returns:

value of element icol, presumed of numeric type

getLongValue

long getLongValue(int icol)

Returns the value of a given column as a long. If that element of the tuple is not of numeric type, the result may not be useful.

Parameters:

icol - column index

Returns:

value of element icol, presumed of numeric type

getBooleanValue

boolean getBooleanValue(int icol)

Returns the value of a given column as a boolean. If that element of the table is not of boolean type, the result may not be useful.

Parameters:

icol - column index

Returns:

value of element icol, presumed of boolean type