Package org.apache.druid.segment

Class VirtualColumns

java.lang.Object

org.apache.druid.segment.VirtualColumns

All Implemented Interfaces:

Cacheable

public class VirtualColumns
extends Object
implements Cacheable

Class allowing lookup and usage of virtual columns.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	VirtualColumns.JsonIncludeFilter	JsonInclude filter for getVirtualColumns().

Field Summary

Fields

Modifier and Type	Field	Description
static VirtualColumns	EMPTY

Method Summary

Modifier and Type	Method	Description
boolean	canVectorize(ColumnInspector columnInspector)
static VirtualColumns	create(List<VirtualColumn> virtualColumns)
static VirtualColumns	create(VirtualColumn... virtualColumns)
boolean	equals(Object o)
boolean	exists(String columnName)	Returns true if a virtual column exists with a particular columnName.
byte[]	getCacheKey()	Get a byte array used as a cache key.
ColumnCapabilities	getColumnCapabilities(ColumnInspector inspector, String columnName)
ColumnCapabilities	getColumnCapabilitiesWithFallback(ColumnInspector inspector, String columnName)
List<String>	getColumnNames()
ColumnIndexSupplier	getIndexSupplier(String columnName, ColumnSelector columnSelector)	Get the ColumnIndexSupplier of the specified virtual column, with the assistance of a ColumnSelector to allow reading things from segments.
VirtualColumn	getVirtualColumn(String columnName)
VirtualColumn[]	getVirtualColumns()
int	hashCode()
boolean	isEmpty()
ColumnValueSelector<?>	makeColumnValueSelector(String columnName, ColumnSelectorFactory factory)	Create a column value selector.
ColumnValueSelector<?>	makeColumnValueSelector(String columnName, ColumnSelector columnSelector, ReadableOffset offset)	Try to create an optimized value selector directly from a ColumnSelector.
DimensionSelector	makeDimensionSelector(DimensionSpec dimensionSpec, ColumnSelectorFactory factory)	Create a dimension (string) selector.
DimensionSelector	makeDimensionSelector(DimensionSpec dimensionSpec, ColumnSelector columnSelector, ReadableOffset offset)	Try to create an optimized dimension (string) selector directly from a ColumnSelector.
MultiValueDimensionVectorSelector	makeMultiValueDimensionVectorSelector(DimensionSpec dimensionSpec, ColumnSelector columnSelector, ReadableVectorOffset offset)	Try to create an optimized multi value dimension (string) vector selector, directly from a ColumnSelector.
MultiValueDimensionVectorSelector	makeMultiValueDimensionVectorSelector(DimensionSpec dimensionSpec, VectorColumnSelectorFactory factory)	Create a multi value dimension vector (string) selector.
SingleValueDimensionVectorSelector	makeSingleValueDimensionVectorSelector(DimensionSpec dimensionSpec, ColumnSelector columnSelector, ReadableVectorOffset offset)	Try to create an optimized single value dimension (string) vector selector, directly from a ColumnSelector.
SingleValueDimensionVectorSelector	makeSingleValueDimensionVectorSelector(DimensionSpec dimensionSpec, VectorColumnSelectorFactory factory)	Create a single value dimension vector (string) selector.
VectorObjectSelector	makeVectorObjectSelector(String columnName, ColumnSelector columnSelector, ReadableVectorOffset offset)	Try to create an optimized vector object selector directly from a ColumnSelector.If this method returns null, callers should try to fallback to makeVectorObjectSelector(String, VectorColumnSelectorFactory) instead.
VectorObjectSelector	makeVectorObjectSelector(String columnName, VectorColumnSelectorFactory factory)	Create a column vector object selector.
VectorValueSelector	makeVectorValueSelector(String columnName, ColumnSelector columnSelector, ReadableVectorOffset offset)	Try to create an optimized vector value selector directly from a ColumnSelector.
VectorValueSelector	makeVectorValueSelector(String columnName, VectorColumnSelectorFactory factory)	Create a column vector value selector.
static VirtualColumns	nullToEmpty(VirtualColumns virtualColumns)
static boolean	shouldVectorize(Query<?> query, VirtualColumns virtualColumns, ColumnInspector inspector)
static Pair<String,String>	splitColumnName(String columnName)	Split a dot-style columnName into the "main" columnName and the subColumn name after the dot.
String	toString()
ColumnSelectorFactory	wrap(ColumnSelectorFactory baseFactory)	Creates a VirtualizedColumnSelectorFactory which can create column selectors for virtualColumns in addition to selectors for all physical columns in the underlying factory.
ColumnInspector	wrapInspector(ColumnInspector inspector)	Creates a VirtualizedColumnInspector that provides ColumnCapabilities information for all virtualColumns in addition to the capabilities of all physical columns in the underlying inspector.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY

public static final VirtualColumns EMPTY

Method Detail

splitColumnName

public static Pair<String,String> splitColumnName(String columnName)

Split a dot-style columnName into the "main" columnName and the subColumn name after the dot. Useful for columns that support dot notation.

Parameters:

columnName - columnName like "foo" or "foo.bar"

Returns:

pair of main column name (will not be null) and subColumn name (may be null)

create

public static VirtualColumns create(List<VirtualColumn> virtualColumns)

create

public static VirtualColumns create(VirtualColumn... virtualColumns)

nullToEmpty

public static VirtualColumns nullToEmpty(@Nullable
                                         VirtualColumns virtualColumns)

shouldVectorize

public static boolean shouldVectorize(Query<?> query,
                                      VirtualColumns virtualColumns,
                                      ColumnInspector inspector)

exists

public boolean exists(String columnName)

Returns true if a virtual column exists with a particular columnName.

Parameters:

columnName - the column name

Returns:

true or false

getVirtualColumn

@Nullable
public VirtualColumn getVirtualColumn(String columnName)

getIndexSupplier

@Nullable
public ColumnIndexSupplier getIndexSupplier(String columnName,
                                            ColumnSelector columnSelector)

Get the ColumnIndexSupplier of the specified virtual column, with the assistance of a ColumnSelector to allow reading things from segments. If the column does not have indexes this method may return null, or may also return a non-null supplier whose methods may return null values - having a supplier is no guarantee that the column has indexes.

makeDimensionSelector

public DimensionSelector makeDimensionSelector(DimensionSpec dimensionSpec,
                                               ColumnSelectorFactory factory)

Create a dimension (string) selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeDimensionSelector

@Nullable
public DimensionSelector makeDimensionSelector(DimensionSpec dimensionSpec,
                                               ColumnSelector columnSelector,
                                               ReadableOffset offset)

Try to create an optimized dimension (string) selector directly from a ColumnSelector. If this method returns null, callers should try to fallback to makeDimensionSelector(DimensionSpec, ColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeColumnValueSelector

public ColumnValueSelector<?> makeColumnValueSelector(String columnName,
                                                      ColumnSelectorFactory factory)

Create a column value selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeColumnValueSelector

@Nullable
public ColumnValueSelector<?> makeColumnValueSelector(String columnName,
                                                      ColumnSelector columnSelector,
                                                      ReadableOffset offset)

Try to create an optimized value selector directly from a ColumnSelector. If this method returns null, callers should try to fallback to makeColumnValueSelector(String, ColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

canVectorize

public boolean canVectorize(ColumnInspector columnInspector)

makeSingleValueDimensionVectorSelector

public SingleValueDimensionVectorSelector makeSingleValueDimensionVectorSelector(DimensionSpec dimensionSpec,
                                                                                 VectorColumnSelectorFactory factory)

Create a single value dimension vector (string) selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeSingleValueDimensionVectorSelector

@Nullable
public SingleValueDimensionVectorSelector makeSingleValueDimensionVectorSelector(DimensionSpec dimensionSpec,
                                                                                 ColumnSelector columnSelector,
                                                                                 ReadableVectorOffset offset)

Try to create an optimized single value dimension (string) vector selector, directly from a ColumnSelector. If this method returns null, callers should try to fallback to makeSingleValueDimensionVectorSelector(DimensionSpec, VectorColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeMultiValueDimensionVectorSelector

public MultiValueDimensionVectorSelector makeMultiValueDimensionVectorSelector(DimensionSpec dimensionSpec,
                                                                               VectorColumnSelectorFactory factory)

Create a multi value dimension vector (string) selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeMultiValueDimensionVectorSelector

@Nullable
public MultiValueDimensionVectorSelector makeMultiValueDimensionVectorSelector(DimensionSpec dimensionSpec,
                                                                               ColumnSelector columnSelector,
                                                                               ReadableVectorOffset offset)

Try to create an optimized multi value dimension (string) vector selector, directly from a ColumnSelector. If this method returns null, callers should try to fallback to makeMultiValueDimensionVectorSelector(DimensionSpec, VectorColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeVectorValueSelector

public VectorValueSelector makeVectorValueSelector(String columnName,
                                                   VectorColumnSelectorFactory factory)

Create a column vector value selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeVectorValueSelector

@Nullable
public VectorValueSelector makeVectorValueSelector(String columnName,
                                                   ColumnSelector columnSelector,
                                                   ReadableVectorOffset offset)

Try to create an optimized vector value selector directly from a ColumnSelector. If this method returns null, callers should try to fallback to makeVectorValueSelector(String, VectorColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeVectorObjectSelector

public VectorObjectSelector makeVectorObjectSelector(String columnName,
                                                     VectorColumnSelectorFactory factory)

Create a column vector object selector.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

makeVectorObjectSelector

@Nullable
public VectorObjectSelector makeVectorObjectSelector(String columnName,
                                                     ColumnSelector columnSelector,
                                                     ReadableVectorOffset offset)

Try to create an optimized vector object selector directly from a ColumnSelector.If this method returns null, callers should try to fallback to makeVectorObjectSelector(String, VectorColumnSelectorFactory) instead.

Throws:

IllegalArgumentException - if the virtual column does not exist (see exists(String)

getColumnCapabilities

@Nullable
public ColumnCapabilities getColumnCapabilities(ColumnInspector inspector,
                                                String columnName)

getColumnCapabilitiesWithFallback

@Nullable
public ColumnCapabilities getColumnCapabilitiesWithFallback(ColumnInspector inspector,
                                                            String columnName)

getVirtualColumns

public VirtualColumn[] getVirtualColumns()

wrap

public ColumnSelectorFactory wrap(ColumnSelectorFactory baseFactory)

Creates a VirtualizedColumnSelectorFactory which can create column selectors for virtualColumns in addition to selectors for all physical columns in the underlying factory.

wrapInspector

public ColumnInspector wrapInspector(ColumnInspector inspector)

Creates a VirtualizedColumnInspector that provides ColumnCapabilities information for all virtualColumns in addition to the capabilities of all physical columns in the underlying inspector.

getCacheKey

public byte[] getCacheKey()

Description copied from interface: Cacheable

Get a byte array used as a cache key.

Specified by:

getCacheKey in interface Cacheable

Returns:

a cache key

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

isEmpty

public boolean isEmpty()

getColumnNames

public List<String> getColumnNames()