org.apache.drill.exec.physical.impl.scan.convert

Class StandardConversions

java.lang.Object

org.apache.drill.exec.physical.impl.scan.convert.StandardConversions

public class StandardConversions
extends Object

Factory for standard conversions as outlined in the package header. Use the builder to add schema-wide properties from a provided schema, from context-specific properties or both.

The class provides two kinds of information:

• A description of the conversion: whether the conversion is supported, whether it is lossy, and the class that can do the conversion.
• As a concrete conversion factory which provides the conversion class if needed, the original column writer if no conversion is needed, or null if the conversion is not supported.

This class is not suitable if a reader requires a source-specific column converter or conversion rules. In that case, create a source-specific conversion factory.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StandardConversions.Builder
static class	StandardConversions.ConversionDefn Definition of a conversion including conversion type and the standard conversion class (if available.)
static class	StandardConversions.ConversionType Indicates the type of conversion needed.

Field Summary

Fields

Modifier and Type	Field and Description
static StandardConversions.ConversionDefn	EXPLICIT
static StandardConversions.ConversionDefn	IMPLICIT
static StandardConversions.ConversionDefn	IMPLICIT_UNSAFE

Method Summary

Modifier and Type	Method and Description
StandardConversions.ConversionDefn	analyze(ColumnMetadata inputSchema, ColumnMetadata outputSchema) Create converters for standard cases.
StandardConversions.ConversionDefn	analyze(TypeProtos.MinorType inputType, ColumnMetadata outputSchema)
static StandardConversions.Builder	builder()
ValueWriter	converterFor(ScalarWriter scalarWriter, ColumnMetadata inputSchema)
ValueWriter	converterFor(ScalarWriter scalarWriter, TypeProtos.MinorType inputType)
ValueWriter	converterFor(ScalarWriter scalarWriter, TypeProtos.MinorType inputType, Map<String,String> columnProps) Create a direct column converter, if necessary, for the given input type and optional properties.
Class<? extends DirectConverter>	convertFromVarchar(ColumnMetadata outputDefn)
DirectConverter	newInstance(Class<? extends DirectConverter> conversionClass, ScalarWriter baseWriter)
DirectConverter	newInstance(Class<? extends DirectConverter> conversionClass, ScalarWriter baseWriter, Map<String,String> properties)

Methods inherited from class java.lang.Object

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

Field Detail

IMPLICIT

public static final StandardConversions.ConversionDefn IMPLICIT

IMPLICIT_UNSAFE

public static final StandardConversions.ConversionDefn IMPLICIT_UNSAFE

EXPLICIT

public static final StandardConversions.ConversionDefn EXPLICIT

Method Detail

builder

public static StandardConversions.Builder builder()

newInstance

public DirectConverter newInstance(Class<? extends DirectConverter> conversionClass,
                                   ScalarWriter baseWriter,
                                   Map<String,String> properties)

newInstance

public DirectConverter newInstance(Class<? extends DirectConverter> conversionClass,
                                   ScalarWriter baseWriter)

analyze

public StandardConversions.ConversionDefn analyze(ColumnMetadata inputSchema,
                                                  ColumnMetadata outputSchema)

Create converters for standard cases.

Does not support any of the "legacy" decimal types.

Parameters:

inputSchema - the column schema for the input column which the client code (e.g. reader) wants to produce

outputSchema - the column schema for the output vector to be produced by this operator

Returns:

a description of the conversion needed (if any), along with the standard conversion class, if available

analyze

public StandardConversions.ConversionDefn analyze(TypeProtos.MinorType inputType,
                                                  ColumnMetadata outputSchema)

convertFromVarchar

public Class<? extends DirectConverter> convertFromVarchar(ColumnMetadata outputDefn)

converterFor

public ValueWriter converterFor(ScalarWriter scalarWriter,
                                TypeProtos.MinorType inputType,
                                Map<String,String> columnProps)

Create a direct column converter, if necessary, for the given input type and optional properties. The properties provide formats and other type conversion hints needed for some conversions.

Parameters:

scalarWriter - the output column writer

inputType - the type of the input data

columnProps - optional properties for some string-based conversions

Returns:

a column converter, if needed and available, the input writer if no conversion is needed, or null if there is no conversion available

converterFor

public ValueWriter converterFor(ScalarWriter scalarWriter,
                                TypeProtos.MinorType inputType)

converterFor

public ValueWriter converterFor(ScalarWriter scalarWriter,
                                ColumnMetadata inputSchema)