com.metamatrix.query.function.aggregate
Class Avg

java.lang.Object
  com.metamatrix.query.function.aggregate.Sum
      com.metamatrix.query.function.aggregate.Avg

All Implemented Interfaces:

AggregateFunction

public class Avg
extends Sum

Accumulates (per tuple) and calculates the average of the values of a column. The type of the result varies depending on the type of the input AggregateSymbol - the type will not be an integral type but will always be some kind of decimal type.

Field Summary

Fields inherited from class com.metamatrix.query.function.aggregate.Sum

accumulatorType, BIG_DECIMAL, BIG_INTEGER, DOUBLE, LONG

Constructor Summary

Avg()
Constructor for Avg.

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) Called to initialize the function.
void	reset() Called to reset the state of the function.

Methods inherited from class com.metamatrix.query.function.aggregate.Sum

getAccumulatorType

Methods inherited from class java.lang.Object

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

Constructor Detail

Avg

public Avg()

Constructor for Avg.

Method Detail

initialize

public void initialize(java.lang.Class dataType)

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

Overrides:

initialize in class Sum

Parameters:

dataType - Data type of element begin aggregated

See Also:

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

reset

public void reset()

Description copied from interface: AggregateFunction

Called to reset the state of the function.

Specified by:

reset in interface AggregateFunction

Overrides:

reset in class Sum

addInput

public void addInput(java.lang.Object input)
              throws FunctionExecutionException,
                     ExpressionEvaluationException,
                     MetaMatrixComponentException

Description copied from interface: AggregateFunction

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

Specified by:

addInput in interface AggregateFunction

Overrides:

addInput in class Sum

Parameters:

input - Input value, may be null

Throws:

FunctionExecutionException

ExpressionEvaluationException

MetaMatrixComponentException

See Also:

AggregateFunction.addInput(Object)

getResult

public java.lang.Object getResult()
                           throws FunctionExecutionException,
                                  ExpressionEvaluationException,
                                  MetaMatrixComponentException

Description copied from interface: AggregateFunction

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

Specified by:

getResult in interface AggregateFunction

Overrides:

getResult in class Sum

Returns:

Result value

Throws:

FunctionExecutionException

ExpressionEvaluationException

MetaMatrixComponentException

See Also:

AggregateFunction.getResult()