Package org.apache.druid.common.config

Class NullHandling

java.lang.Object

org.apache.druid.common.config.NullHandling

public class NullHandling
extends Object

Helper class for NullHandling. This class is used to switch between SQL compatible Null Handling behavior introduced as part of https://github.com/apache/druid/issues/4349 and the old druid behavior where null values are replaced with default values e.g Null Strings are replaced with empty values.

Field Summary

Fields

Modifier and Type	Field	Description
static byte	IS_NOT_NULL_BYTE
static byte	IS_NULL_BYTE
static Double	ZERO_DOUBLE	use these values to ensure that defaultDoubleValue(), defaultFloatValue() , defaultFloatValue() return the same boxed object when returning a constant zero
static Float	ZERO_FLOAT
static Long	ZERO_LONG

Constructor Summary

Constructors

Constructor	Description
NullHandling()

Method Summary

Modifier and Type	Method	Description
static Double	defaultDoubleValue()
static Float	defaultFloatValue()
static Long	defaultLongValue()
static String	defaultStringValue()
static <T> T	defaultValueForClass(Class<T> clazz)	Returns the default value for an object of the provided class.
static Object	defaultValueForType(ValueType type)	Returns the default value for the given ValueType.
static String	emptyToNullIfNeeded(String value)
static boolean	ignoreNullsForStringCardinality()	whether nulls should be counted during String cardinality
static void	initializeForTests()	Many unit tests do not setup modules for this value to be injected, this method provides a manual way to initialize INSTANCE
static void	initializeForTestsWithValues(Boolean useDefForNull, Boolean ignoreNullForString)
static void	initializeForTestsWithValues(Boolean useDefForNull, Boolean useThreeValueLogic, Boolean ignoreNullForString)
static boolean	isNullOrEquivalent(String value)
static boolean	isNullOrEquivalent(ByteBuffer buffer)
static boolean	mustCombineNullAndEmptyInDictionary(Indexed<ByteBuffer> dictionaryUtf8)	Given a UTF-8 dictionary, returns whether the first two entries must be coalesced into a single null entry.
static boolean	mustReplaceFirstValueWithNullInDictionary(Indexed<ByteBuffer> dictionaryUtf8)	Given a UTF-8 dictionary, returns whether the first entry must be replaced with null.
static String	nullToEmptyIfNeeded(String value)
static boolean	replaceWithDefault()	whether nulls should be replaced with default value.
static boolean	sqlCompatible()
static boolean	useThreeValueLogic()

Methods inherited from class java.lang.Object

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

Field Detail

ZERO_DOUBLE

public static final Double ZERO_DOUBLE

use these values to ensure that defaultDoubleValue(), defaultFloatValue() , defaultFloatValue() return the same boxed object when returning a constant zero

ZERO_FLOAT

public static final Float ZERO_FLOAT

ZERO_LONG

public static final Long ZERO_LONG

IS_NULL_BYTE

public static final byte IS_NULL_BYTE

See Also:

Constant Field Values

IS_NOT_NULL_BYTE

public static final byte IS_NOT_NULL_BYTE

See Also:

Constant Field Values

Constructor Detail

NullHandling

public NullHandling()

Method Detail

initializeForTests

public static void initializeForTests()

Many unit tests do not setup modules for this value to be injected, this method provides a manual way to initialize INSTANCE

initializeForTestsWithValues

public static void initializeForTestsWithValues(Boolean useDefForNull,
                                                Boolean ignoreNullForString)

initializeForTestsWithValues

public static void initializeForTestsWithValues(Boolean useDefForNull,
                                                Boolean useThreeValueLogic,
                                                Boolean ignoreNullForString)

replaceWithDefault

public static boolean replaceWithDefault()

whether nulls should be replaced with default value.

ignoreNullsForStringCardinality

public static boolean ignoreNullsForStringCardinality()

whether nulls should be counted during String cardinality

sqlCompatible

public static boolean sqlCompatible()

useThreeValueLogic

public static boolean useThreeValueLogic()

nullToEmptyIfNeeded

@Nullable
public static String nullToEmptyIfNeeded(@Nullable
                                         String value)

emptyToNullIfNeeded

@Nullable
public static String emptyToNullIfNeeded(@Nullable
                                         String value)

defaultStringValue

@Nullable
public static String defaultStringValue()

defaultLongValue

@Nullable
public static Long defaultLongValue()

defaultFloatValue

@Nullable
public static Float defaultFloatValue()

defaultDoubleValue

@Nullable
public static Double defaultDoubleValue()

defaultValueForClass

@Nullable
public static <T> T defaultValueForClass(Class<T> clazz)

Returns the default value for an object of the provided class. Will be null in SQL-compatible null handling mode. May be null or some non-null default value when not in SQL-compatible null handling mode.

defaultValueForType

@Nullable
public static Object defaultValueForType(ValueType type)

Returns the default value for the given ValueType. May be null or non-null based on the current SQL-compatible null handling mode.

isNullOrEquivalent

public static boolean isNullOrEquivalent(@Nullable
                                         String value)

isNullOrEquivalent

public static boolean isNullOrEquivalent(@Nullable
                                         ByteBuffer buffer)

mustCombineNullAndEmptyInDictionary

public static boolean mustCombineNullAndEmptyInDictionary(Indexed<ByteBuffer> dictionaryUtf8)

Given a UTF-8 dictionary, returns whether the first two entries must be coalesced into a single null entry. This happens if we are in default-value mode and the first two entries are null and empty string. This and mustReplaceFirstValueWithNullInDictionary(Indexed) are never both true. Provided to enable compatibility for segments written under sqlCompatible() mode but read under replaceWithDefault() mode.

mustReplaceFirstValueWithNullInDictionary

public static boolean mustReplaceFirstValueWithNullInDictionary(Indexed<ByteBuffer> dictionaryUtf8)

Given a UTF-8 dictionary, returns whether the first entry must be replaced with null. This happens if we are in default-value mode and the first entry is an empty string. (Default-value mode expects it to be null.) This and mustCombineNullAndEmptyInDictionary(Indexed) are never both true. Provided to enable compatibility for segments written under sqlCompatible() mode but read under replaceWithDefault() mode.