org.axiondb.functions
Class CountFunction

java.lang.Object
  org.axiondb.BaseSelectable
      org.axiondb.functions.BaseFunction
          org.axiondb.functions.BaseAggregateFunction
              org.axiondb.functions.CountFunction

All Implemented Interfaces:

java.io.Serializable, Function, FunctionFactory, AggregateFunction, ConcreteFunction, Selectable

public class CountFunction
extends BaseAggregateFunction
implements AggregateFunction, FunctionFactory

COUNT: an aggregate function returning the number of rows.

Version:

$Revision: 1.9 $ $Date: 2005/04/24 21:33:11 $

See Also:

Serialized Form

Field Summary

Fields inherited from class org.axiondb.BaseSelectable

_hash

Constructor Summary

CountFunction()

Method Summary

java.lang.Object	evaluate(RowDecoratorIterator rows)
DataType	getDataType()
ConcreteFunction	makeNewInstance()

Methods inherited from class org.axiondb.functions.BaseAggregateFunction

acceptable, evaluate, isDistinct, isValid, setDistinct, setDistinct

Methods inherited from class org.axiondb.functions.BaseFunction

addArgument, getArgument, getArgumentCount, setArgument, setVariableContext, toString

Methods inherited from class org.axiondb.BaseSelectable

getAlias, getLabel, getName, setAlias, setName

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.axiondb.functions.ConcreteFunction

isValid

Methods inherited from interface org.axiondb.Function

addArgument, getAlias, getArgument, getArgumentCount, getName, setAlias, setArgument

Methods inherited from interface org.axiondb.Selectable

evaluate, getLabel, setVariableContext

Constructor Detail

CountFunction

public CountFunction()

Method Detail

makeNewInstance

public ConcreteFunction makeNewInstance()

Specified by:

makeNewInstance in interface FunctionFactory

getDataType

public DataType getDataType()

Specified by:

getDataType in interface Selectable

Specified by:

getDataType in class BaseFunction

evaluate

public java.lang.Object evaluate(RowDecoratorIterator rows)
                          throws AxionException

Specified by:

evaluate in interface AggregateFunction

Throws:

AxionException