Package net.sf.jasperreports.engine.fill

Class JRCalculator

java.lang.Object

net.sf.jasperreports.engine.fill.JRCalculator

All Implemented Interfaces:

JRFillExpressionEvaluator

public class JRCalculator
extends Object
implements JRFillExpressionEvaluator

Evaluates JasperReports expressions.

The expressions calculator is the entity inside JasperReports that evaluates expressions and increments variables or datasets at report-filling time. When a report template is compiled, the report compiler produces and stores in the compiled report template (JasperReport object) information that it will use at report-filling time to build an instance of the JRCalculator class.

The Java-based report compilers generate a Java source file and compile it on the fly. This generated class is a subclass of the JRCalculator, and the bytecode produced by compiling it is stored inside the JasperReport object. At report-filling time, this bytecode is loaded and the resulting class is instantiated to obtain the calculator object needed for expression evaluation.

Only the report compiler creates the calculator instance because only the report compiler can make sense of the information it stored in the compiled report template at report compilation time.

Author:

Teodor Danciu (teodord@users.sourceforge.net)

Field Summary

Fields

Modifier and Type	Field	Description
protected JRFillDataset	dataset
protected JRFillElementDataset[]	datasets
protected Map<String,JRFillField>	fldsm
protected JRFillGroup[]	groups
protected Map<String,JRFillGroup>	grpsm
protected Map<String,JRFillParameter>	parsm
protected JRFillVariable[]	variables
protected Map<String,JRFillVariable>	varsm

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	JRCalculator(DatasetExpressionEvaluator evaluator)	Creates a calculator using an expression evaluator.
protected	JRCalculator(JREvaluator evaluator)	Creates a calculator using an expression evaluator.

Method Summary

Modifier and Type	Method	Description
void	calculateVariables(boolean incrementDatasets)
void	estimateGroupRuptures()	Determines group breaks based on estimated report values.
void	estimateVariables()
Object	evaluate(JRExpression expression)
Object	evaluate(JRExpression expression, byte evaluationType)	Evaluates an expression.
Object	evaluateEstimated(JRExpression expression)
Object	evaluateOld(JRExpression expression)
JRFillVariable	getColumnNumber()
JRFillDataset	getFillDataset()	Returns the dataset used by the expression evaluator.
JRFillVariable	getPageNumber()
protected void	init(JRFillDataset dataset)	Initializes the calculator.
void	initializeVariables(ResetTypeEnum resetType, IncrementTypeEnum incrementType)
protected void	recalculateVariables()

Methods inherited from class java.lang.Object

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

Field Detail

dataset

protected JRFillDataset dataset

parsm

protected Map<String,JRFillParameter> parsm

fldsm

protected Map<String,JRFillField> fldsm

varsm

protected Map<String,JRFillVariable> varsm

grpsm

protected Map<String,JRFillGroup> grpsm

variables

protected JRFillVariable[] variables

groups

protected JRFillGroup[] groups

datasets

protected JRFillElementDataset[] datasets

Constructor Detail

JRCalculator

protected JRCalculator(DatasetExpressionEvaluator evaluator)

Creates a calculator using an expression evaluator.

Parameters:

evaluator - the expression evaluator

JRCalculator

protected JRCalculator(JREvaluator evaluator)

Creates a calculator using an expression evaluator.

Parameters:

evaluator - the expression evaluator

Method Detail

init

protected void init(JRFillDataset dataset)
             throws JRException

Initializes the calculator.

Parameters:

dataset - the dataset this calculator is used for

Throws:

JRException

getPageNumber

public JRFillVariable getPageNumber()

getColumnNumber

public JRFillVariable getColumnNumber()

calculateVariables

public void calculateVariables(boolean incrementDatasets)
                        throws JRException

Throws:

JRException

recalculateVariables

protected void recalculateVariables()
                             throws JRException

Throws:

JRException

estimateVariables

public void estimateVariables()
                       throws JRException

Throws:

JRException

estimateGroupRuptures

public void estimateGroupRuptures()
                           throws JRException

Determines group breaks based on estimated report values.

estimateVariables() needs to be called prior to this method.

Throws:

JRException

initializeVariables

public void initializeVariables(ResetTypeEnum resetType,
                                IncrementTypeEnum incrementType)
                         throws JRException

Throws:

JRException

evaluate

public Object evaluate(JRExpression expression,
                       byte evaluationType)
                throws JRException

Description copied from interface: JRFillExpressionEvaluator

Evaluates an expression.

Specified by:

evaluate in interface JRFillExpressionEvaluator

Parameters:

expression - the expression to evaluate

evaluationType - one of JRExpression.EVALUATION_DEFAULT, JRExpression.EVALUATION_OLD, JRExpression.EVALUATION_ESTIMATED

Returns:

the result

Throws:

JRException

evaluateOld

public Object evaluateOld(JRExpression expression)
                   throws JRExpressionEvalException

Throws:

JRExpressionEvalException

evaluateEstimated

public Object evaluateEstimated(JRExpression expression)
                         throws JRExpressionEvalException

Throws:

JRExpressionEvalException

evaluate

public Object evaluate(JRExpression expression)
                throws JRExpressionEvalException

Throws:

JRExpressionEvalException

getFillDataset

public JRFillDataset getFillDataset()

Description copied from interface: JRFillExpressionEvaluator

Returns the dataset used by the expression evaluator.

Specified by:

getFillDataset in interface JRFillExpressionEvaluator