org.apache.derby.iapi.store.raw

Class FetchDescriptor

java.lang.Object

org.apache.derby.iapi.store.raw.FetchDescriptor

public final class FetchDescriptor
extends java.lang.Object

FetchDescriptor is used to package up all the arguments necessary to describe what rows and what row parts should be returned from the store back to language as part of a fetch.

The FetchDescriptor may also contain scratch space used to process the qualifiers passed in the scan. This scratch space will be used to cache information about the qualifiers, valid column list, row size so that calculations need only be done once per scan rather than every iteration.

Constructor Summary

Constructors

Constructor and Description
FetchDescriptor(int input_row_length)
FetchDescriptor(int input_row_length, FormatableBitSet input_validColumns, Qualifier[][] input_qualifier_list)
FetchDescriptor(int input_row_length, int single_valid_column_number)

Method Summary

Modifier and Type	Method and Description
int[]	getMaterializedColumns() Internal to store.
int	getMaxFetchColumnId() Internal to store.
Qualifier[][]	getQualifierList() Return the qualifier array.
FormatableBitSet	getValidColumns() Return the column list bit map.
int[]	getValidColumnsArray()
void	reset() Internal to store.
void	setValidColumns(FormatableBitSet input_validColumns)

Methods inherited from class java.lang.Object

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

Constructor Detail

FetchDescriptor

public FetchDescriptor(int input_row_length)

FetchDescriptor

public FetchDescriptor(int input_row_length,
                       int single_valid_column_number)

FetchDescriptor

public FetchDescriptor(int input_row_length,
                       FormatableBitSet input_validColumns,
                       Qualifier[][] input_qualifier_list)

Method Detail

getValidColumns

public final FormatableBitSet getValidColumns()

Return the column list bit map.

A description of which columns to return from every fetch in the scan. A row array and a valid column bit map work together to describe the row to be returned by the scan - see RowUtil for description of how these two parameters work together to describe a "row".

Returns:

The column list bit map.

getValidColumnsArray

public final int[] getValidColumnsArray()

setValidColumns

public final void setValidColumns(FormatableBitSet input_validColumns)

getQualifierList

public final Qualifier[][] getQualifierList()

Return the qualifier array.

Return the array of qualifiers in this FetchDescriptor. The array of qualifiers which, applied to each key, restricts the rows returned by the scan. Rows for which any one of the qualifiers returns false are not returned by the scan. If null, all rows are returned. Qualifiers can only reference columns which are included in the scanColumnList. The column id that a qualifier returns in the column id the table, not the column id in the partial row being returned.

A null qualifier array means there are no qualifiers.

Returns:

The qualifier array, it may be null.

getMaterializedColumns

public final int[] getMaterializedColumns()

Internal to store.

getMaxFetchColumnId

public final int getMaxFetchColumnId()

Internal to store.

reset

public final void reset()

Internal to store.