Type Parameters:

S -

All Superinterfaces:

Serializable
```
public interface RowScanMapper<S>
extends Serializable
```
A row mapper which is able to update a state as it reads rows. Only use this if RowMapper cannot be used.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`S`	`combine(S left, S right)`	Combines two states produced by rows.
`static <S> RowScanMapper<S>`	`conditionalMapper(RowFilter filter, RowScanMapper<S> rowScanMapper, RowMapper negativeMapper)`	Restricts a `RowScanMapper` to only aggregate its state on filtered rows, and only apply the map function to those filtered rows.
`S`	`feed(long rowId, Row row)`	Produces the state associated with a given row.
`Row`	`map(S state, long rowId, Row row)`	Given the accumulated state of all the previous rows (the list of states produced by feed and merged using combine), transform the current row to a new one.
`default boolean`	`preservesRecordStructure()`	Whether this mapper is guaranteed to preserve record structure after application.
`S`	`unit()`	The initial state of the mapper.

- Method Detail
  - feed
```
S feed(long rowId,
       Row row)
```
    Produces the state associated with a given row.
    
    Parameters:
    
    rowId - the index of the row
    
    row - the row to map to the corresponding state
  - combine
```
S combine(S left,
          S right)
```
    Combines two states produced by rows. This needs to be associative and unital (for the unit provided below).
  - unit
```
S unit()
```
    The initial state of the mapper.
  - map
```
Row map(S state,
        long rowId,
        Row row)
```
    Given the accumulated state of all the previous rows (the list of states produced by feed and merged using combine), transform the current row to a new one.
  - preservesRecordStructure
```
default boolean preservesRecordStructure()
```
    Whether this mapper is guaranteed to preserve record structure after application.
  - conditionalMapper
```
static <S> RowScanMapper<S> conditionalMapper(RowFilter filter,
                                              RowScanMapper<S> rowScanMapper,
                                              RowMapper negativeMapper)
```
    Restricts a RowScanMapper to only aggregate its state on filtered rows, and only apply the map function to those filtered rows. A stateless mapper is applied to the other rows.
    
    Type Parameters:
    
    S - the internal state of the mapper
    
    Parameters:
    
    filter - the row filter used to determine which mapper to apply to a given row
    
    rowScanMapper - the mapper for rows selected by the filter
    
    negativeMapper - the mapper for rows not selected by the filter

Interface RowScanMapper<S>

Method Summary

Method Detail

feed

combine

unit

map

preservesRecordStructure

conditionalMapper