parquet.column

Enum Encoding

java.lang.Object

java.lang.Enum<Encoding>

parquet.column.Encoding

All Implemented Interfaces:

Serializable, Comparable<Encoding>

public enum Encoding
extends Enum<Encoding>

encoding of the data

Author:

Julien Le Dem

Enum Constant Summary

Enum Constants

Enum Constant and Description
BIT_PACKED Deprecated.
GROUP_VAR_INT
PLAIN
PLAIN_DICTIONARY
RLE Actually a combination of bit packing and run length encoding.

Method Summary

Methods

Modifier and Type	Method and Description
ValuesReader	getDictionaryBasedValuesReader(ColumnDescriptor descriptor, ValuesType valuesType, Dictionary dictionary) To read decoded values that require a dictionary
ValuesReader	getValuesReader(ColumnDescriptor descriptor, ValuesType valuesType) To read decoded values that don't require a dictionary
Dictionary	initDictionary(ColumnDescriptor descriptor, DictionaryPage dictionaryPage) initializes a dictionary from a page
boolean	usesDictionary()
static Encoding	valueOf(String name) Returns the enum constant of this type with the specified name.
static Encoding[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

PLAIN

public static final Encoding PLAIN

RLE

public static final Encoding RLE

Actually a combination of bit packing and run length encoding. TODO: Should we rename this to be more clear?

BIT_PACKED

@Deprecated
public static final Encoding BIT_PACKED

Deprecated.

This is no longer used, and has been replaced by RLE which is combination of bit packing and rle

GROUP_VAR_INT

public static final Encoding GROUP_VAR_INT

PLAIN_DICTIONARY

public static final Encoding PLAIN_DICTIONARY

Method Detail

values

public static Encoding[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Encoding c : Encoding.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Encoding valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

usesDictionary

public boolean usesDictionary()

Returns:

whether this encoding requires a dictionary

initDictionary

public Dictionary initDictionary(ColumnDescriptor descriptor,
                        DictionaryPage dictionaryPage)
                          throws IOException

initializes a dictionary from a page

Parameters:

dictionaryPage -

Returns:

the corresponding dictionary

Throws:

IOException

getValuesReader

public ValuesReader getValuesReader(ColumnDescriptor descriptor,
                           ValuesType valuesType)

To read decoded values that don't require a dictionary

Parameters:

descriptor - the column to read

valuesType - the type of values

Returns:

the proper values reader for the given column

getDictionaryBasedValuesReader

public ValuesReader getDictionaryBasedValuesReader(ColumnDescriptor descriptor,
                                          ValuesType valuesType,
                                          Dictionary dictionary)

To read decoded values that require a dictionary

Parameters:

descriptor - the column to read

valuesType - the type of values

dictionary - the dictionary

Returns:

the proper values reader for the given column