Package org.apache.druid.segment

Class RestrictedCursorFactory

java.lang.Object

org.apache.druid.segment.RestrictedCursorFactory

All Implemented Interfaces:

Expr.InputBindingInspector, ColumnInspector, CursorFactory

public class RestrictedCursorFactory
extends Object
implements CursorFactory

A factory class for creating Cursor instances with strict adherence to Policy restrictions. Created by RestrictedSegment.asCursorFactory(), and applies policies transparently.

The CursorFactory simplifies the process of initializing and retrieving Cursor objects while ensuring that any cursor created complies with the Policy restrictions.

Policy enforcement in makeCursorHolder(org.apache.druid.segment.CursorBuildSpec):

• Row-level restrictions are enforced by adding filters to CursorBuildSpec, which is then passed to delegate for execution. This ensures that only relevant data are accessible by the client.

Constructor Summary

Constructors

Constructor	Description
RestrictedCursorFactory(CursorFactory delegate, Policy policy)

Method Summary

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 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.InputBindingInspector

areNumeric, areNumeric, areSameTypes, areSameTypes, areScalar, areScalar, canVectorize, canVectorize

Constructor Detail

RestrictedCursorFactory

public RestrictedCursorFactory(CursorFactory delegate,
                               Policy policy)

Method Detail

makeCursorHolder

public CursorHolder makeCursorHolder(CursorBuildSpec spec)

Specified by:

makeCursorHolder in interface CursorFactory

getRowSignature

public RowSignature getRowSignature()

Description copied from interface: CursorFactory

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.

Specified by:

getRowSignature in interface CursorFactory

getColumnCapabilities

@Nullable
public ColumnCapabilities getColumnCapabilities(String column)

Description copied from interface: CursorFactory

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

Specified by:

getColumnCapabilities in interface CursorFactory

Parameters:

column - column name

Returns:

capabilities, or null