Package org.apache.druid.segment

Class ColumnProcessors

java.lang.Object

org.apache.druid.segment.ColumnProcessors

public class ColumnProcessors
extends Object

Creates "column processors", which are objects that wrap a single input column and provide some functionality on top of it.

See Also:

• which this may eventually replace

Field Summary

Fields

Modifier and Type	Field	Description
static final ColumnCapabilities	NIL_COLUMN_CAPABILITIES	Capabilites that are used when we return a nil selector for a nonexistent column.

Constructor Summary

Constructors

Constructor	Description
ColumnProcessors()

Method Summary

Modifier and Type	Method	Description
static <T> T	makeProcessor(String column, ColumnProcessorFactory<T> processorFactory, ColumnSelectorFactory selectorFactory)	Make a processor for a particular named column.
static <T> T	makeProcessor(Expr expr, ColumnType exprTypeHint, ColumnProcessorFactory<T> processorFactory, ColumnSelectorFactory selectorFactory)	Make a processor for a particular expression.
static <T> T	makeProcessor(DimensionSpec dimensionSpec, ColumnProcessorFactory<T> processorFactory, ColumnSelectorFactory selectorFactory)	Make a processor for a particular DimensionSpec.
static <T> T	makeVectorProcessor(String column, VectorColumnProcessorFactory<T> processorFactory, VectorColumnSelectorFactory selectorFactory)	Make a processor for a particular named column.
static <T> T	makeVectorProcessor(DimensionSpec dimensionSpec, VectorColumnProcessorFactory<T> processorFactory, VectorColumnSelectorFactory selectorFactory)	Make a processor for a particular DimensionSpec.
static boolean	useDictionaryEncodedSelector(ColumnCapabilities capabilities)	Checks the ColumnCapabilities to see if the column has a dictionary available (ColumnCapabilities.isDictionaryEncoded() is true), and there is a unique mapping of dictionary id to value (ColumnCapabilities.areDictionaryValuesUnique() is true).

Methods inherited from class java.lang.Object

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

Field Details

NIL_COLUMN_CAPABILITIES

public static final ColumnCapabilities NIL_COLUMN_CAPABILITIES

Capabilites that are used when we return a nil selector for a nonexistent column.

Constructor Details

ColumnProcessors

public ColumnProcessors()

Method Details

makeProcessor

public static <T> T makeProcessor(String column,
 ColumnProcessorFactory<T> processorFactory,
 ColumnSelectorFactory selectorFactory)

Make a processor for a particular named column.

Type Parameters:

T - processor type

Parameters:

column - the column

processorFactory - the processor factory

selectorFactory - the column selector factory

makeProcessor

public static <T> T makeProcessor(DimensionSpec dimensionSpec,
 ColumnProcessorFactory<T> processorFactory,
 ColumnSelectorFactory selectorFactory)

Make a processor for a particular DimensionSpec.

Type Parameters:

T - processor type

Parameters:

dimensionSpec - the dimension spec

processorFactory - the processor factory

selectorFactory - the column selector factory

makeProcessor

public static <T> T makeProcessor(Expr expr,
 ColumnType exprTypeHint,
 ColumnProcessorFactory<T> processorFactory,
 ColumnSelectorFactory selectorFactory)

Make a processor for a particular expression. If the expression is a simple identifier, this behaves identically to makeProcessor(String, ColumnProcessorFactory, ColumnSelectorFactory) and accesses the column directly. Otherwise, it uses an expression selector of type exprTypeHint.

Type Parameters:

T - processor type

Parameters:

expr - the parsed expression

exprTypeHint - expression selector type to use for exprs that are not simple identifiers

processorFactory - the processor factory

selectorFactory - the column selector factory

makeVectorProcessor

public static <T> T makeVectorProcessor(String column,
 VectorColumnProcessorFactory<T> processorFactory,
 VectorColumnSelectorFactory selectorFactory)

Make a processor for a particular named column.

Type Parameters:

T - processor type

Parameters:

column - the column

processorFactory - the processor factory

selectorFactory - the column selector factory

makeVectorProcessor

public static <T> T makeVectorProcessor(DimensionSpec dimensionSpec,
 VectorColumnProcessorFactory<T> processorFactory,
 VectorColumnSelectorFactory selectorFactory)

Make a processor for a particular DimensionSpec.

Type Parameters:

T - processor type

Parameters:

dimensionSpec - the dimension spec

processorFactory - the processor factory

selectorFactory - the column selector factory

useDictionaryEncodedSelector

public static boolean useDictionaryEncodedSelector(ColumnCapabilities capabilities)

Checks the ColumnCapabilities to see if the column has a dictionary available (ColumnCapabilities.isDictionaryEncoded() is true), and there is a unique mapping of dictionary id to value (ColumnCapabilities.areDictionaryValuesUnique() is true).