com.metamatrix.query.function.aggregate
Class Count

java.lang.Object
  com.metamatrix.query.function.aggregate.Count

All Implemented Interfaces:

AggregateFunction

public class Count
extends java.lang.Object
implements AggregateFunction

Just a simple COUNT() implementation that counts every non-null row it sees.

Constructor Summary

Count()
Constructor for Count.

Method Summary

void	addInput(java.lang.Object input) Called for the element value in every row of a group.
java.lang.Object	getResult() Called after all values have been processed to get the result.
void	initialize(java.lang.Class dataType, java.lang.Class inputType) Called to initialize the function.
void	reset() Called to reset the state of the function.

Methods inherited from class java.lang.Object

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

Constructor Detail

Count

public Count()

Constructor for Count.

Method Detail

initialize

public void initialize(java.lang.Class dataType,
                       java.lang.Class inputType)

Description copied from interface: AggregateFunction

Called to initialize the function. In the future this may expand with additional information.

Specified by:

initialize in interface AggregateFunction

Parameters:

dataType - Data type of element begin aggregated

See Also:

com.metamatrix.query.function.aggregate.AggregateFunction#initialize(String, Class)

reset

public void reset()

Description copied from interface: AggregateFunction

Called to reset the state of the function.

Specified by:

reset in interface AggregateFunction

addInput

public void addInput(java.lang.Object input)

Description copied from interface: AggregateFunction

Called for the element value in every row of a group.

Specified by:

addInput in interface AggregateFunction

Parameters:

input - Input value, may be null

See Also:

AggregateFunction.addInput(Object)

getResult

public java.lang.Object getResult()

Description copied from interface: AggregateFunction

Called after all values have been processed to get the result.

Specified by:

getResult in interface AggregateFunction

Returns:

Result value

See Also:

AggregateFunction.getResult()