CursorFactory (druid-processing 32.0.0 API)

All Superinterfaces:

ColumnInspector, Expr.InputBindingInspector

All Known Implementing Classes:

ColumnarFrameCursorFactory, FilteredCursorFactory, HashJoinSegmentCursorFactory, IncrementalIndexCursorFactory, QueryableIndexCursorFactory, RestrictedCursorFactory, RowBasedCursorFactory, RowFrameCursorFactory, UnnestCursorFactory
```
public interface CursorFactory
extends ColumnInspector
```

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`ColumnCapabilities`	`getColumnCapabilities(String column)`	Returns capabilities of a particular column, if known.
`RowSignature`	`getRowSignature()`	Returns the `RowSignature` of the data available from this cursor factory.
`CursorHolder`	`makeCursorHolder(CursorBuildSpec spec)`

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

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingInspector
areNumeric, areNumeric, areSameTypes, areSameTypes, areScalar, areScalar, canVectorize, canVectorize

- Method Detail
  - makeCursorHolder
```
CursorHolder makeCursorHolder(CursorBuildSpec spec)
```
  - getRowSignature
```
RowSignature getRowSignature()
```
    Returns the RowSignature of the data available from this cursor factory. For mutable segments, even though the signature may evolve over time, any particular object returned by this method is an immutable snapshot.
  - getColumnCapabilities
```
@Nullable
ColumnCapabilities getColumnCapabilities(String column)
```
    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. Note that CursorFactory are representations of "real" segments, so they are not aware of any virtual columns that may be involved in a query. In general, query engines should instead use the method ColumnSelectorFactory.getColumnCapabilities(String), which returns capabilities for virtual columns as well.
    
    Specified by:
    
    getColumnCapabilities in interface ColumnInspector
    
    Parameters:
    
    column - column name
    
    Returns:
    
    capabilities, or null