org.apache.drill.exec.vector.accessor.reader

Class AbstractTupleReader

java.lang.Object

org.apache.drill.exec.vector.accessor.reader.AbstractTupleReader

All Implemented Interfaces:

ColumnReader, ReaderEvents, TupleReader

Direct Known Subclasses:

DictEntryReader, MapReader, RowSetReaderImpl

public abstract class AbstractTupleReader
extends Object
implements TupleReader, ReaderEvents

Reader for a tuple (a row or a map.) Provides access to each column using either a name or a numeric index.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractTupleReader.TupleObjectReader

Field Summary

Fields

Modifier and Type	Field and Description
protected NullStateReader	nullStateReader
protected AbstractObjectReader[]	readers

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractTupleReader(AbstractObjectReader[] readers)

Method Summary

Modifier and Type	Method and Description
ArrayReader	array(int colIndex)
ArrayReader	array(String colName)
void	bindBuffer()
void	bindIndex(ColumnReaderIndex index)
void	bindNullState(NullStateReader nullStateReader)
ObjectReader	column(int colIndex) Return a column reader by column index as reported by the associated metadata.
ObjectReader	column(String colName) Return a column reader by name.
int	columnCount()
DictReader	dict(int colIndex)
DictReader	dict(String colName)
String	getAsString() Return the entire object as a string.
Object	getObject() Return the value of the underlying data as a Java object.
boolean	isNull() Determine if this value is null.
NullStateReader	nullStateReader()
void	reposition()
ScalarReader	scalar(int colIndex)
ScalarReader	scalar(String colName)
TupleReader	tuple(int colIndex)
TupleReader	tuple(String colName)
ObjectType	type() The type of this reader.
ObjectType	type(int colIndex)
ObjectType	type(String colName)
VariantReader	variant(int colIndex)
VariantReader	variant(String colName)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.vector.accessor.TupleReader

tupleSchema

Methods inherited from interface org.apache.drill.exec.vector.accessor.ColumnReader

schema

Field Detail

readers

protected final AbstractObjectReader[] readers

nullStateReader

protected NullStateReader nullStateReader

Constructor Detail

AbstractTupleReader

protected AbstractTupleReader(AbstractObjectReader[] readers)

Method Detail

type

public ObjectType type()

Description copied from interface: ColumnReader

The type of this reader.

Specified by:

type in interface ColumnReader

Returns:

type of reader

bindIndex

public void bindIndex(ColumnReaderIndex index)

Specified by:

bindIndex in interface ReaderEvents

bindNullState

public void bindNullState(NullStateReader nullStateReader)

Specified by:

bindNullState in interface ReaderEvents

bindBuffer

public void bindBuffer()

Specified by:

bindBuffer in interface ReaderEvents

nullStateReader

public NullStateReader nullStateReader()

Specified by:

nullStateReader in interface ReaderEvents

isNull

public boolean isNull()

Description copied from interface: ColumnReader

Determine if this value is null.

• Nullable scalar: determine if the value is null.
• Non-nullable scalar: always returns false.
• Arrays: always returns false
• Lists: determine if the list for the current row is null. In a list, an array entry can be null, empty, or can contain items. In repeated types, the array itself is never null. If the array is null, then it implicitly has no entries.
• Map or Repeated Map: Always returns false.
• Map inside a union, or in a list that contains a union, the tuple itself can be null.
• Union: Determine if the current value is null. Null values have no type and no associated reader.

Specified by:

isNull in interface ColumnReader

Returns:

true if this value is null; false otherwise

columnCount

public int columnCount()

Specified by:

columnCount in interface TupleReader

column

public ObjectReader column(int colIndex)

Description copied from interface: TupleReader

Return a column reader by column index as reported by the associated metadata.

Specified by:

column in interface TupleReader

Parameters:

colIndex - column index

Returns:

reader for the column

column

public ObjectReader column(String colName)

Description copied from interface: TupleReader

Return a column reader by name.

Specified by:

column in interface TupleReader

Parameters:

colName - column name

Returns:

reader for the column, or null if no such column exists

type

public ObjectType type(int colIndex)

Specified by:

type in interface TupleReader

type

public ObjectType type(String colName)

Specified by:

type in interface TupleReader

scalar

public ScalarReader scalar(int colIndex)

Specified by:

scalar in interface TupleReader

scalar

public ScalarReader scalar(String colName)

Specified by:

scalar in interface TupleReader

tuple

public TupleReader tuple(int colIndex)

Specified by:

tuple in interface TupleReader

tuple

public TupleReader tuple(String colName)

Specified by:

tuple in interface TupleReader

array

public ArrayReader array(int colIndex)

Specified by:

array in interface TupleReader

array

public ArrayReader array(String colName)

Specified by:

array in interface TupleReader

variant

public VariantReader variant(int colIndex)

Specified by:

variant in interface TupleReader

variant

public VariantReader variant(String colName)

Specified by:

variant in interface TupleReader

dict

public DictReader dict(int colIndex)

Specified by:

dict in interface TupleReader

dict

public DictReader dict(String colName)

Specified by:

dict in interface TupleReader

reposition

public void reposition()

Specified by:

reposition in interface ReaderEvents

getObject

public Object getObject()

Description copied from interface: ColumnReader

Return the value of the underlying data as a Java object. Primarily for testing

• Array: Return the entire array as an List of objects. Note, even if the array is scalar, the elements are still returned as a list.

Specified by:

getObject in interface ColumnReader

Returns:

the value as a Java object

getAsString

public String getAsString()

Description copied from interface: ColumnReader

Return the entire object as a string. Primarily for debugging.

Specified by:

getAsString in interface ColumnReader

Returns:

string representation of the object