org.apache.avro.specific

Class SpecificData

java.lang.Object

org.apache.avro.generic.GenericData

org.apache.avro.specific.SpecificData

Direct Known Subclasses:

ReflectData

public class SpecificData
extends GenericData

Utilities for generated Java classes and interfaces.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	SpecificData.SchemaConstructable Tag interface that indicates that a class has a one-argument constructor that accepts a Schema.

Nested classes/interfaces inherited from class org.apache.avro.generic.GenericData

GenericData.Array<T>, GenericData.EnumSymbol, GenericData.Fixed, GenericData.InstanceSupplier, GenericData.Record, GenericData.StringType

Field Summary

Fields

Modifier and Type	Field and Description
static String	CLASS_PROP
static String	ELEMENT_PROP
static String	KEY_CLASS_PROP
static Set<String>	RESERVED_WORDS List of Java reserved words from https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.9 combined with the boolean and null literals.
protected Set<Class>	stringableClasses Read/write some common builtin classes as strings.

Fields inherited from class org.apache.avro.generic.GenericData

FAST_READER_PROP, STRING_PROP, STRING_TYPE_STRING

Constructor Summary

Constructors

Constructor and Description
SpecificData() For subclasses.
SpecificData(ClassLoader classLoader) Construct with a specific classloader.

Method Summary

Modifier and Type	Method and Description
protected int	compare(Object o1, Object o2, Schema s, boolean eq) Comparison implementation.
DatumReader	createDatumReader(Schema schema) Returns a DatumReader for this kind of data.
DatumReader	createDatumReader(Schema writer, Schema reader) Returns a DatumReader for this kind of data.
DatumWriter	createDatumWriter(Schema schema) Returns a DatumWriter for this kind of data.
Object	createEnum(String symbol, Schema schema) Called to create an enum value.
Object	createFixed(Object old, Schema schema) Called to create an fixed value.
protected Schema	createSchema(Type type, Map<String,Schema> names) Create the schema for a Java type.
static SpecificData	get() Return the singleton instance.
Class	getClass(Schema schema) Return the class that implements a schema, or null if none exists.
static String	getClassName(Schema schema) Returns the Java class name indicated by a schema's name and namespace.
static BinaryDecoder	getDecoder(ObjectInput in) Runtime utility used by generated classes.
static BinaryEncoder	getEncoder(ObjectOutput out) Runtime utility used by generated classes.
protected Schema	getEnumSchema(Object datum) Called to obtain the schema of a enum.
static <T> SpecificData	getForClass(Class<T> c) If the given class is assignable to SpecificRecordBase, this method returns the SpecificData instance from the field MODEL$, in order to get the correct Conversion instances for the class.
static SpecificData	getForSchema(Schema reader) For RECORD type schemas, this method returns the SpecificData instance of the class associated with the schema, in order to get the right conversions for any logical types used.
GenericData.InstanceSupplier	getNewRecordSupplier(Schema schema) create a supplier that allows to get new record instances for a given schema in an optimized way
Protocol	getProtocol(Class iface) Return the protocol for a Java interface.
Schema	getSchema(Type type) Find the schema for a Java type.
protected String	getSchemaName(Object datum) Return the schema full name for a datum.
protected boolean	isEnum(Object datum) Called by the default implementation of GenericData.instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isStringable(Class<?> c) True if a class should be serialized with toString().
protected boolean	isStringType(Class<?> c) True if a class IS a string type
static Object	newInstance(Class c, Schema s) Create an instance of a class.
Object	newRecord(Object old, Schema schema) Called to create new record instances.
void	setCustomCoders(boolean flag) Dynamically set the value of the custom-coder feature flag.
boolean	useCustomCoders() Retrieve the current value of the custom-coders feature flag.

Methods inherited from class org.apache.avro.generic.GenericData

addLogicalTypeConversion, compare, createFixed, deepCopy, getArrayAsCollection, getClassLoader, getConversionByClass, getConversionByClass, getConversionFor, getConversions, getDefaultValue, getFastReaderBuilder, getField, getField, getFixedSchema, getRecordSchema, getRecordState, hashCode, hashCodeAdd, induce, instanceOf, isArray, isBoolean, isBytes, isDouble, isFastReaderEnabled, isFixed, isFloat, isInteger, isLong, isMap, isRecord, isString, newArray, newMap, resolveUnion, setFastReaderEnabled, setField, setField, setStringType, toString, toString, validate

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_PROP

public static final String CLASS_PROP

See Also:

Constant Field Values

KEY_CLASS_PROP

public static final String KEY_CLASS_PROP

See Also:

Constant Field Values

ELEMENT_PROP

public static final String ELEMENT_PROP

See Also:

Constant Field Values

RESERVED_WORDS

public static final Set<String> RESERVED_WORDS

List of Java reserved words from https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.9 combined with the boolean and null literals. combined with the classnames used internally in the generated avro code.

stringableClasses

protected Set<Class> stringableClasses

Read/write some common builtin classes as strings. Representing these as strings isn't always best, as they aren't always ordered ideally, but at least they're stored. Also note that, for compatibility, only classes that wouldn't be otherwise correctly readable or writable should be added here, e.g., those without a no-arg constructor or those whose fields are all transient.

Constructor Detail

SpecificData

public SpecificData()

For subclasses. Applications normally use get().

SpecificData

public SpecificData(ClassLoader classLoader)

Construct with a specific classloader.

Method Detail

createDatumReader

public DatumReader createDatumReader(Schema schema)

Description copied from class: GenericData

Returns a DatumReader for this kind of data.

Overrides:

createDatumReader in class GenericData

createDatumReader

public DatumReader createDatumReader(Schema writer,
                                     Schema reader)

Description copied from class: GenericData

Returns a DatumReader for this kind of data.

Overrides:

createDatumReader in class GenericData

createDatumWriter

public DatumWriter createDatumWriter(Schema schema)

Description copied from class: GenericData

Returns a DatumWriter for this kind of data.

Overrides:

createDatumWriter in class GenericData

get

public static SpecificData get()

Return the singleton instance.

getForSchema

public static SpecificData getForSchema(Schema reader)

For RECORD type schemas, this method returns the SpecificData instance of the class associated with the schema, in order to get the right conversions for any logical types used.

Parameters:

reader - the reader schema

Returns:

the SpecificData associated with the schema's class, or the default instance.

getForClass

public static <T> SpecificData getForClass(Class<T> c)

If the given class is assignable to SpecificRecordBase, this method returns the SpecificData instance from the field MODEL$, in order to get the correct Conversion instances for the class. Falls back to the default instance get() for other classes or if the field is not found.

Type Parameters:

T - .

Parameters:

c - A class

Returns:

The SpecificData from the SpecificRecordBase instance, or the default SpecificData instance.

useCustomCoders

public boolean useCustomCoders()

Retrieve the current value of the custom-coders feature flag. Defaults to true, but this default can be overriden using the system property org.apache.avro.specific.use_custom_coders, and can be set dynamically by useCustomCoders(). See for more about this feature flag.

setCustomCoders

public void setCustomCoders(boolean flag)

Dynamically set the value of the custom-coder feature flag. See useCustomCoders().

isEnum

protected boolean isEnum(Object datum)

Description copied from class: GenericData

Called by the default implementation of GenericData.instanceOf(org.apache.avro.Schema, java.lang.Object).

Overrides:

isEnum in class GenericData

createEnum

public Object createEnum(String symbol,
                         Schema schema)

Description copied from class: GenericData

Called to create an enum value. May be overridden for alternate enum representations. By default, returns a GenericEnumSymbol.

Overrides:

createEnum in class GenericData

getEnumSchema

protected Schema getEnumSchema(Object datum)

Description copied from class: GenericData

Called to obtain the schema of a enum. By default calls {GenericContainer#getSchema(). May be overridden for alternate enum representations.

Overrides:

getEnumSchema in class GenericData

getClass

public Class getClass(Schema schema)

Return the class that implements a schema, or null if none exists.

getClassName

public static String getClassName(Schema schema)

Returns the Java class name indicated by a schema's name and namespace.

getSchema

public Schema getSchema(Type type)

Find the schema for a Java type.

createSchema

protected Schema createSchema(Type type,
                              Map<String,Schema> names)

Create the schema for a Java type.

getSchemaName

protected String getSchemaName(Object datum)

Description copied from class: GenericData

Return the schema full name for a datum. Called by GenericData.resolveUnion(Schema,Object).

Overrides:

getSchemaName in class GenericData

isStringable

protected boolean isStringable(Class<?> c)

True if a class should be serialized with toString().

isStringType

protected boolean isStringType(Class<?> c)

True if a class IS a string type

getProtocol

public Protocol getProtocol(Class iface)

Return the protocol for a Java interface.

compare

protected int compare(Object o1,
                      Object o2,
                      Schema s,
                      boolean eq)

Description copied from class: GenericData

Comparison implementation. When equals is true, only checks for equality, not for order.

Overrides:

compare in class GenericData

newInstance

public static Object newInstance(Class c,
                                 Schema s)

Create an instance of a class. If the class implements SpecificData.SchemaConstructable, call a constructor with a Schema parameter, otherwise use a no-arg constructor.

createFixed

public Object createFixed(Object old,
                          Schema schema)

Description copied from class: GenericData

Called to create an fixed value. May be overridden for alternate fixed representations. By default, returns GenericFixed.

Overrides:

createFixed in class GenericData

newRecord

public Object newRecord(Object old,
                        Schema schema)

Description copied from class: GenericData

Called to create new record instances. Subclasses may override to use a different record implementation. The returned instance must conform to the schema provided. If the old object contains fields not present in the schema, they should either be removed from the old object, or it should create a new instance that conforms to the schema. By default, this returns a GenericData.Record.

Overrides:

newRecord in class GenericData

getNewRecordSupplier

public GenericData.InstanceSupplier getNewRecordSupplier(Schema schema)

Description copied from class: GenericData

create a supplier that allows to get new record instances for a given schema in an optimized way

Overrides:

getNewRecordSupplier in class GenericData

getDecoder

public static BinaryDecoder getDecoder(ObjectInput in)

Runtime utility used by generated classes.

getEncoder

public static BinaryEncoder getEncoder(ObjectOutput out)

Runtime utility used by generated classes.