Package org.pentaho.reporting.engine.classic.core.function

Class CountDistinctFunction

java.lang.Object

org.pentaho.reporting.engine.classic.core.function.AbstractExpression

org.pentaho.reporting.engine.classic.core.function.AbstractFunction

org.pentaho.reporting.engine.classic.core.function.CountDistinctFunction

All Implemented Interfaces:

Serializable, Cloneable, EventListener, ReportListener, AggregationFunction, Expression, FieldAggregationFunction, Function

public class CountDistinctFunction
extends AbstractFunction
implements FieldAggregationFunction

Counts the distinct occurrences of an certain value of an column. This functionality is similar to the SQL distinct() function.

Author:

Thomas Morgner

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
CountDistinctFunction()	DefaultConstructor.

Method Summary

Modifier and Type	Method	Description
Object	clone()	Clones the expression.
String	getCrosstabFilterGroup()
String	getField()	Returns the field used by the function.
String	getGroup()	Returns the group name.
Expression	getInstance()	Return a completly separated copy of this function.
Object	getValue()	Return the number of distint values for the given column.
void	groupStarted(ReportEvent event)	Receives notification that a group has started.
boolean	isIgnoreNullValues()
void	itemsAdvanced(ReportEvent event)	Receives notification that a row of data is being processed.
void	reportInitialized(ReportEvent event)	Receives notification that report generation initializes the current run.
void	setCrosstabFilterGroup(String crosstabFilterGroup)
void	setField(String field)	Sets the field name for the function.
void	setGroup(String name)	Sets the group name.
void	setIgnoreNullValues(boolean ignoreNullValues)
void	summaryRowSelection(ReportEvent event)	A crosstab specific event notifying crosstab-aware functions to select the result for the summary row cell that will be printed next.

Methods inherited from class org.pentaho.reporting.engine.classic.core.function.AbstractFunction

groupFinished, itemsFinished, itemsStarted, reportDone, reportFinished, reportStarted

Methods inherited from class org.pentaho.reporting.engine.classic.core.function.AbstractExpression

getDataRow, getDependencyLevel, getName, getReportConfiguration, getResourceBundleFactory, getRuntime, isActive, isDeepTraversing, isPreserve, setActive, setDependencyLevel, setName, setPreserve, setRuntime

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.pentaho.reporting.engine.classic.core.function.Expression

getDataRow, getDependencyLevel, getName, getReportConfiguration, getResourceBundleFactory, getRuntime, isActive, isDeepTraversing, isPreserve, setDependencyLevel, setName, setRuntime

Methods inherited from interface org.pentaho.reporting.engine.classic.core.event.ReportListener

groupFinished, itemsFinished, itemsStarted, reportDone, reportFinished, reportStarted

Constructor Detail

CountDistinctFunction

public CountDistinctFunction()

DefaultConstructor.

Method Detail

isIgnoreNullValues

public boolean isIgnoreNullValues()

setIgnoreNullValues

public void setIgnoreNullValues(boolean ignoreNullValues)

getGroup

public String getGroup()

Returns the group name.

Specified by:

getGroup in interface AggregationFunction

Returns:

The group name.

setGroup

public void setGroup(String name)

Sets the group name.

If a group is defined, the running total is reset to zero at the start of every instance of this group.

Specified by:

setGroup in interface AggregationFunction

Parameters:

name - the group name (null permitted).

getField

public String getField()

Returns the field used by the function. The field name corresponds to a column name in the report's data-row.

Specified by:

getField in interface FieldAggregationFunction

Returns:

The field name.

setField

public void setField(String field)

Sets the field name for the function. The field name corresponds to a column name in the report's data-row.

Specified by:

setField in interface FieldAggregationFunction

Parameters:

field - the field name.

reportInitialized

public void reportInitialized(ReportEvent event)

Receives notification that report generation initializes the current run.

The event carries a ReportState.Started state. Use this to initialize the report.

Specified by:

reportInitialized in interface ReportListener

Overrides:

reportInitialized in class AbstractFunction

Parameters:

event - The event.

groupStarted

public void groupStarted(ReportEvent event)

Receives notification that a group has started.

Specified by:

groupStarted in interface ReportListener

Overrides:

groupStarted in class AbstractFunction

Parameters:

event - the event.

itemsAdvanced

public void itemsAdvanced(ReportEvent event)

Receives notification that a row of data is being processed.

Specified by:

itemsAdvanced in interface ReportListener

Overrides:

itemsAdvanced in class AbstractFunction

Parameters:

event - the event.

getValue

public Object getValue()

Return the number of distint values for the given column.

Specified by:

getValue in interface Expression

Returns:

the value of the function.

summaryRowSelection

public void summaryRowSelection(ReportEvent event)

Description copied from class: AbstractFunction

A crosstab specific event notifying crosstab-aware functions to select the result for the summary row cell that will be printed next.

Specified by:

summaryRowSelection in interface ReportListener

Overrides:

summaryRowSelection in class AbstractFunction

Parameters:

event - The report event.

getInstance

public Expression getInstance()

Return a completly separated copy of this function. The copy does no longer share any changeable objects with the original function.

Specified by:

getInstance in interface Expression

Overrides:

getInstance in class AbstractExpression

Returns:

a copy of this function.

clone

public Object clone()
             throws CloneNotSupportedException

Clones the expression. The expression should be reinitialized after the cloning.

Expressions maintain no state, cloning is done at the beginning of the report processing to disconnect the expression from any other object space.

Specified by:

clone in interface Expression

Overrides:

clone in class AbstractExpression

Returns:

a clone of this expression.

Throws:

CloneNotSupportedException - this should never happen.

getCrosstabFilterGroup

public String getCrosstabFilterGroup()

Specified by:

getCrosstabFilterGroup in interface AggregationFunction

setCrosstabFilterGroup

public void setCrosstabFilterGroup(String crosstabFilterGroup)

Specified by:

setCrosstabFilterGroup in interface AggregationFunction