org.apache.druid.segment

Class RowBasedColumnSelectorFactory<T>

java.lang.Object

org.apache.druid.segment.RowBasedColumnSelectorFactory<T>

All Implemented Interfaces:

Expr.InputBindingTypes, ColumnInspector, ColumnSelectorFactory

public class RowBasedColumnSelectorFactory<T>
extends Object
implements ColumnSelectorFactory

A ColumnSelectorFactory that is based on an object supplier and a RowAdapter for that type of object.

Method Summary

Modifier and Type	Method and Description
static <RowType> RowBasedColumnSelectorFactory<RowType>	create(RowAdapter<RowType> adapter, Supplier<RowType> supplier, RowSignature signature, boolean throwParseExceptions) Create an instance based on any object, along with a RowAdapter for that object.
ColumnCapabilities	getColumnCapabilities(String columnName) Returns capabilities of a particular column, if known.
ColumnValueSelector<?>	makeColumnValueSelector(String columnName) Returns ColumnValueSelector corresponding to the given column name, or NilColumnValueSelector if the column with such name is absent.
DimensionSelector	makeDimensionSelector(DimensionSpec dimensionSpec)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.segment.ColumnInspector

getType

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingTypes

areNumeric, areNumeric, canVectorize, canVectorize

Method Detail

create

public static <RowType> RowBasedColumnSelectorFactory<RowType> create(RowAdapter<RowType> adapter,
                                                                      Supplier<RowType> supplier,
                                                                      RowSignature signature,
                                                                      boolean throwParseExceptions)

Create an instance based on any object, along with a RowAdapter for that object.

Parameters:

adapter - adapter for these row objects

supplier - supplier of row objects

signature - will be used for reporting available columns and their capabilities. Note that the this factory will still allow creation of selectors on any named field in the rows, even if it doesn't appear in "rowSignature". (It only needs to be accessible via RowAdapter.columnFunction(java.lang.String).) As a result, you can achieve an untyped mode by passing in RowSignature.empty().

throwParseExceptions - whether numeric selectors should throw parse exceptions or use a default/null value when their inputs are not actually numeric

makeDimensionSelector

public DimensionSelector makeDimensionSelector(DimensionSpec dimensionSpec)

Specified by:

makeDimensionSelector in interface ColumnSelectorFactory

makeColumnValueSelector

public ColumnValueSelector<?> makeColumnValueSelector(String columnName)

Description copied from interface: ColumnSelectorFactory

Returns ColumnValueSelector corresponding to the given column name, or NilColumnValueSelector if the column with such name is absent.

Specified by:

makeColumnValueSelector in interface ColumnSelectorFactory

getColumnCapabilities

@Nullable
public ColumnCapabilities getColumnCapabilities(String columnName)

Description copied from interface: ColumnSelectorFactory

Returns capabilities of a particular column, if known. May be null if the column doesn't exist, or if the column does exist but the capabilities are unknown. The latter is possible with dynamically discovered columns.

Specified by:

getColumnCapabilities in interface ColumnInspector

Specified by:

getColumnCapabilities in interface ColumnSelectorFactory

Parameters:

columnName - column name

Returns:

capabilities, or null