Package net.sf.jasperreports.engine.fill

Interface JRExtendedIncrementer

All Superinterfaces:

JRIncrementer

All Known Implementing Classes:

JRAbstractExtendedIncrementer

public interface JRExtendedIncrementer
extends JRIncrementer

Extended incrementer interface.

The JRIncrementer has been kept for backward compatibility.

The crosstab calculation engine requires extended incrementers. An incrementer implementing JRIncrementer can be used for report variables only.

Author:

Lucian Chirita (lucianc@users.sourceforge.net)

Method Summary

Modifier and Type	Method	Description
Object	combine(JRCalculable calculable, JRCalculable calculableValue, AbstractValueProvider valueProvider)	Combines two calculated values into one.
boolean	ignoresNullValues()	Specifies whether null values are ignored by this incrementer.
Object	increment(JRCalculable calculable, Object expressionValue, AbstractValueProvider valueProvider)	Increments a calculable object with a value.
Object	initialValue()	Returns the initial value for this calculation.

Methods inherited from interface net.sf.jasperreports.engine.fill.JRIncrementer

increment

Method Detail

increment

Object increment(JRCalculable calculable,
                 Object expressionValue,
                 AbstractValueProvider valueProvider)
          throws JRException

Increments a calculable object with a value.

Parameters:

calculable - the calculable

expressionValue - the value

valueProvider - value provider

Returns:

the incremented value

Throws:

JRException

initialValue

Object initialValue()

Returns the initial value for this calculation.

This method should return a neutral value for this calculation (e.g. 0 for sum, 1 for product, etc) or a default value if no neutral value exists.

Returns:

the initial value for this calculation

combine

Object combine(JRCalculable calculable,
               JRCalculable calculableValue,
               AbstractValueProvider valueProvider)
        throws JRException

Combines two calculated values into one.

Parameters:

calculable - the first calculated value

calculableValue - the second calculated value

valueProvider - the value provider used for the helper variables

Returns:

the combined value

Throws:

JRException

ignoresNullValues

boolean ignoresNullValues()

Specifies whether null values are ignored by this incrementer. If null values are ignored, the caller can chose to skip incrementing a calculation with a null value.

Returns:

whether null values are ignored by this incrementer