org.apache.derby.impl.sql.execute
Class GenericAggregator

java.lang.Object
  org.apache.derby.impl.sql.execute.GenericAggregator

 class GenericAggregator
extends java.lang.Object

Adaptor that sits between execution layer and aggregates.

Field Summary

private AggregatorInfo	aggInfo
(package private) int	aggregatorColumnId
private ExecAggregator	cachedAggregator
private ClassFactory	cf
private int	inputColumnId
private int	resultColumnId

Constructor Summary

GenericAggregator(AggregatorInfo aggInfo, ClassFactory cf)
Constructor:

Method Summary

(package private) void	accumulate(DataValueDescriptor inputColumn, DataValueDescriptor aggregatorColumn) Accumulate the aggregate results.
(package private) void	accumulate(ExecRow inputRow, ExecRow accumulateRow) Accumulate the aggregate results.
(package private) void	accumulate(java.lang.Object[] inputRow, java.lang.Object[] accumulateRow) Accumulate the aggregate results.
(package private) boolean	finish(ExecRow row) Get the results of the aggregation and put it in the result column.
(package private) AggregatorInfo	getAggregatorInfo()
(package private) ExecAggregator	getAggregatorInstance() Get a new instance of the aggregator and initialize it.
(package private) int	getColumnId() Return the column id that is being aggregated
(package private) DataValueDescriptor	getInputColumnValue(ExecRow row)
(package private) void	initialize(ExecRow row) Initialize the aggregator
(package private) void	merge(ExecRow inputRow, ExecRow mergeRow) Merge the aggregate results.
(package private) void	merge(java.lang.Object[] inputRow, java.lang.Object[] mergeRow) Merge the aggregate results.
(package private) void	merge(Storable aggregatorColumnIn, Storable aggregatorColumnOut) Merge two partial aggregations.

Methods inherited from class java.lang.Object

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

Field Detail

aggInfo

private final AggregatorInfo aggInfo

aggregatorColumnId

int aggregatorColumnId

inputColumnId

private int inputColumnId

resultColumnId

private int resultColumnId

cf

private final ClassFactory cf

cachedAggregator

private ExecAggregator cachedAggregator

Constructor Detail

GenericAggregator

GenericAggregator(AggregatorInfo aggInfo,
                  ClassFactory cf)

Constructor:

Parameters:

aggInfo - information about the user aggregate

cf - the class factory.

Method Detail

initialize

void initialize(ExecRow row)
          throws StandardException

Initialize the aggregator

Parameters:

row - the row with the aggregator to be initialized

Throws:

StandardException - on error

accumulate

void accumulate(ExecRow inputRow,
                ExecRow accumulateRow)
          throws StandardException

Accumulate the aggregate results. This is the guts of the aggregation. We will call the user aggregate on itself to do the aggregation.

Parameters:

inputRow - the row with the input colum

accumulateRow - the row with the aggregator

Throws:

StandardException - on error

accumulate

void accumulate(java.lang.Object[] inputRow,
                java.lang.Object[] accumulateRow)
          throws StandardException

Accumulate the aggregate results. This is the guts of the aggregation. We will call the user aggregate on itself to do the aggregation.

Parameters:

inputRow - the row with the input colum

accumulateRow - the row with the aggregator

Throws:

StandardException - on error

accumulate

void accumulate(DataValueDescriptor inputColumn,
                DataValueDescriptor aggregatorColumn)
          throws StandardException

Accumulate the aggregate results. This is the guts of the aggregation. We will call the user aggregate on itself to do the aggregation.

Parameters:

inputColumn -

aggregatorColumn -

Throws:

StandardException - on error

merge

void merge(ExecRow inputRow,
           ExecRow mergeRow)
     throws StandardException

Merge the aggregate results. This is the guts of the aggregation. We will call the user aggregate on itself to do the aggregation.

Parameters:

inputRow - the row with the input colum

mergeRow - the row with the aggregator

Throws:

StandardException - on error

merge

void merge(java.lang.Object[] inputRow,
           java.lang.Object[] mergeRow)
     throws StandardException

Merge the aggregate results. This is the guts of the aggregation. We will call the user aggregate on itself to do the aggregation.

Parameters:

inputRow - the row with the input colum

mergeRow - the row with the aggregator

Throws:

StandardException - on error

finish

boolean finish(ExecRow row)
         throws StandardException

Get the results of the aggregation and put it in the result column.

Parameters:

row - the row with the result and the aggregator

Throws:

StandardException - on error

getAggregatorInstance

ExecAggregator getAggregatorInstance()
                               throws StandardException

Get a new instance of the aggregator and initialize it.

Returns:

an exec aggregator

Throws:

StandardException - on error

getColumnId

int getColumnId()

Return the column id that is being aggregated

getInputColumnValue

DataValueDescriptor getInputColumnValue(ExecRow row)
                                  throws StandardException

Throws:

StandardException

merge

void merge(Storable aggregatorColumnIn,
           Storable aggregatorColumnOut)
     throws StandardException

Merge two partial aggregations. This is how the sorter merges partial aggregates.

Throws:

StandardException - on error

getAggregatorInfo

AggregatorInfo getAggregatorInfo()