uk.ac.starlink.ttools.jel

Interface Constant<T>

All Known Implementing Classes:

FixedConstant

public interface Constant<T>

Defines a typed value. Not necessarily constant in that the value will not change, but in the context of the jel package it is not dependent on the column index.

Since:

10 Dec 2007

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
Class<T>	getContentClass() Returns a class of which this object's value will be an instance.
T	getValue() Returns this object's value.
boolean	requiresRowIndex() Indicates whether evaluation of this constant needs to know the row index.

Method Detail

getContentClass

Class<T> getContentClass()

Returns a class of which this object's value will be an instance.

Returns:

content class

getValue

T getValue()

Returns this object's value. Not necessarily always the same.

Returns:

value

requiresRowIndex

boolean requiresRowIndex()

Indicates whether evaluation of this constant needs to know the row index. If executing getValue() may result in a call to StarTableJELRowReader.getCurrentRow(), this method must return true.

Returns:

true if evaluating this constant needs or may need to know the current row index