org.apache.avro.generic

Class GenericData

java.lang.Object

org.apache.avro.generic.GenericData

Direct Known Subclasses:

ProtobufData, SpecificData, ThriftData

public class GenericData
extends Object

Utilities for generic Java data. See GenericRecordBuilder for a convenient way to build GenericRecord instances.

See Also:

GenericRecordBuilder

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericData.Array<T> Default implementation of an array.
static class	GenericData.EnumSymbol Default implementation of GenericEnumSymbol.
static class	GenericData.Fixed Default implementation of GenericFixed.
static class	GenericData.Record Default implementation of GenericRecord.
static class	GenericData.StringType Used to specify the Java type for a string schema.

Field Summary

Fields

Modifier and Type	Field and Description
static String	STRING_PROP
protected static String	STRING_TYPE_STRING

Constructor Summary

Constructors

Constructor and Description
GenericData() For subclasses.
GenericData(ClassLoader classLoader) For subclasses.

Method Summary

Methods

Modifier and Type	Method and Description
void	addLogicalTypeConversion(Conversion<?> conversion) Registers the given conversion to be used when reading and writing with this data model.
int	compare(Object o1, Object o2, Schema s) Compare objects according to their schema.
protected int	compare(Object o1, Object o2, Schema s, boolean equals) 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, byte[] bytes, Schema schema) Called to create an fixed value.
Object	createFixed(Object old, Schema schema) Called to create an fixed value.
<T> T	deepCopy(Schema schema, T value) Makes a deep copy of a value given its schema.
static GenericData	get() Return the singleton instance.
protected Collection	getArrayAsCollection(Object datum) Called to access an array as a collection.
ClassLoader	getClassLoader() Return the class loader that's used (by subclasses).
<T> Conversion<T>	getConversionByClass(Class<T> datumClass) Returns the first conversion found for the given class.
<T> Conversion<T>	getConversionByClass(Class<T> datumClass, LogicalType logicalType) Returns the conversion for the given class and logical type.
Conversion<Object>	getConversionFor(LogicalType logicalType) Returns the Conversion for the given logical type.
Object	getDefaultValue(Schema.Field field) Gets the default value of the given field, if any.
protected Schema	getEnumSchema(Object enu) Called to obtain the schema of a enum.
Object	getField(Object record, String name, int position) Called by GenericDatumReader.readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.io.ResolvingDecoder) to retrieve a record field value from a reused instance.
protected Object	getField(Object record, String name, int pos, Object state) Version of getField(java.lang.Object, java.lang.String, int) that has state.
protected Schema	getFixedSchema(Object fixed) Called to obtain the schema of a fixed.
protected Schema	getRecordSchema(Object record) Called to obtain the schema of a record.
protected Object	getRecordState(Object record, Schema schema) Produce state for repeated calls to getField(Object,String,int,Object) and setField(Object,String,int,Object,Object) on the same record.
protected String	getSchemaName(Object datum) Return the schema full name for a datum.
int	hashCode(Object o, Schema s) Compute a hash code according to a schema, consistent with compare(Object,Object,Schema).
protected int	hashCodeAdd(int hashCode, Object o, Schema s) Add the hash code for an object into an accumulated hash code.
Schema	induce(Object datum) Create a schema given an example datum.
protected boolean	instanceOf(Schema schema, Object datum) Called by resolveUnion(Schema,Object).
protected boolean	isArray(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isBoolean(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isBytes(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isDouble(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isEnum(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isFixed(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isFloat(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isInteger(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isLong(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isMap(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isRecord(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
protected boolean	isString(Object datum) Called by the default implementation of instanceOf(org.apache.avro.Schema, java.lang.Object).
Object	newRecord(Object old, Schema schema) Called to create new record instances.
int	resolveUnion(Schema union, Object datum) Return the index for a datum within a union.
void	setField(Object record, String name, int position, Object o) Called by GenericDatumReader.readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.io.ResolvingDecoder) to set a record fields value to a record instance.
protected void	setField(Object r, String n, int p, Object o, Object state) Version of setField(java.lang.Object, java.lang.String, int, java.lang.Object) that has state.
static void	setStringType(Schema s, GenericData.StringType stringType) Set the Java type to be used when reading this schema.
String	toString(Object datum) Renders a Java datum as JSON.
protected void	toString(Object datum, StringBuilder buffer, IdentityHashMap<Object,Object> seenObjects) Renders a Java datum as JSON.
boolean	validate(Schema schema, Object datum) Returns true if a Java datum matches a schema.

Methods inherited from class java.lang.Object

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

Field Detail

STRING_PROP

public static final String STRING_PROP

See Also:

Constant Field Values

STRING_TYPE_STRING

protected static final String STRING_TYPE_STRING

See Also:

Constant Field Values

Constructor Detail

GenericData

public GenericData()

For subclasses. Applications normally use get().

GenericData

public GenericData(ClassLoader classLoader)

For subclasses. GenericData does not use a ClassLoader.

Method Detail

setStringType

public static void setStringType(Schema s,
                 GenericData.StringType stringType)

Set the Java type to be used when reading this schema. Meaningful only only string schemas and map schemas (for the keys).

get

public static GenericData get()

Return the singleton instance.

getClassLoader

public ClassLoader getClassLoader()

Return the class loader that's used (by subclasses).

addLogicalTypeConversion

public void addLogicalTypeConversion(Conversion<?> conversion)

Registers the given conversion to be used when reading and writing with this data model.

Parameters:

conversion - a logical type Conversion.

getConversionByClass

public <T> Conversion<T> getConversionByClass(Class<T> datumClass)

Returns the first conversion found for the given class.

Parameters:

datumClass - a Class

Returns:

the first registered conversion for the class, or null

getConversionByClass

public <T> Conversion<T> getConversionByClass(Class<T> datumClass,
                                     LogicalType logicalType)

Returns the conversion for the given class and logical type.

Parameters:

datumClass - a Class

logicalType - a LogicalType

Returns:

the conversion for the class and logical type, or null

getConversionFor

public Conversion<Object> getConversionFor(LogicalType logicalType)

Returns the Conversion for the given logical type.

Parameters:

logicalType - a logical type

Returns:

the conversion for the logical type, or null

createDatumReader

public DatumReader createDatumReader(Schema schema)

Returns a DatumReader for this kind of data.

createDatumReader

public DatumReader createDatumReader(Schema writer,
                            Schema reader)

Returns a DatumReader for this kind of data.

createDatumWriter

public DatumWriter createDatumWriter(Schema schema)

Returns a DatumWriter for this kind of data.

validate

public boolean validate(Schema schema,
               Object datum)

Returns true if a Java datum matches a schema.

toString

public String toString(Object datum)

Renders a Java datum as JSON.

toString

protected void toString(Object datum,
            StringBuilder buffer,
            IdentityHashMap<Object,Object> seenObjects)

Renders a Java datum as JSON.

induce

public Schema induce(Object datum)

Create a schema given an example datum.

setField

public void setField(Object record,
            String name,
            int position,
            Object o)

Called by GenericDatumReader.readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.io.ResolvingDecoder) to set a record fields value to a record instance. The default implementation is for IndexedRecord.

getField

public Object getField(Object record,
              String name,
              int position)

Called by GenericDatumReader.readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.io.ResolvingDecoder) to retrieve a record field value from a reused instance. The default implementation is for IndexedRecord.

getRecordState

protected Object getRecordState(Object record,
                    Schema schema)

Produce state for repeated calls to getField(Object,String,int,Object) and setField(Object,String,int,Object,Object) on the same record.

setField

protected void setField(Object r,
            String n,
            int p,
            Object o,
            Object state)

Version of setField(java.lang.Object, java.lang.String, int, java.lang.Object) that has state.

getField

protected Object getField(Object record,
              String name,
              int pos,
              Object state)

Version of getField(java.lang.Object, java.lang.String, int) that has state.

resolveUnion

public int resolveUnion(Schema union,
               Object datum)

Return the index for a datum within a union. Implemented with Schema.getIndexNamed(String) and getSchemaName(Object).

getSchemaName

protected String getSchemaName(Object datum)

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

instanceOf

protected boolean instanceOf(Schema schema,
                 Object datum)

Called by resolveUnion(Schema,Object). May be overridden for alternate data representations.

isArray

protected boolean isArray(Object datum)

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

getArrayAsCollection

protected Collection getArrayAsCollection(Object datum)

Called to access an array as a collection.

isRecord

protected boolean isRecord(Object datum)

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

getRecordSchema

protected Schema getRecordSchema(Object record)

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

isEnum

protected boolean isEnum(Object datum)

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

getEnumSchema

protected Schema getEnumSchema(Object enu)

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

isMap

protected boolean isMap(Object datum)

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

isFixed

protected boolean isFixed(Object datum)

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

getFixedSchema

protected Schema getFixedSchema(Object fixed)

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

isString

protected boolean isString(Object datum)

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

isBytes

protected boolean isBytes(Object datum)

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

isInteger

protected boolean isInteger(Object datum)

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

isLong

protected boolean isLong(Object datum)

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

isFloat

protected boolean isFloat(Object datum)

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

isDouble

protected boolean isDouble(Object datum)

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

isBoolean

protected boolean isBoolean(Object datum)

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

hashCode

public int hashCode(Object o,
           Schema s)

Compute a hash code according to a schema, consistent with compare(Object,Object,Schema).

hashCodeAdd

protected int hashCodeAdd(int hashCode,
              Object o,
              Schema s)

Add the hash code for an object into an accumulated hash code.

compare

public int compare(Object o1,
          Object o2,
          Schema s)

Compare objects according to their schema. If equal, return zero. If greater-than, return 1, if less than return -1. Order is consistent with that of BinaryData.compare(byte[], int, byte[], int, Schema).

compare

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

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

getDefaultValue

public Object getDefaultValue(Schema.Field field)

Gets the default value of the given field, if any.

Parameters:

field - the field whose default value should be retrieved.

Returns:

the default value associated with the given field, or null if none is specified in the schema.

deepCopy

public <T> T deepCopy(Schema schema,
             T value)

Makes a deep copy of a value given its schema.

Logical types are converted to raw types, copied, then converted back.

Parameters:

schema - the schema of the value to deep copy.

value - the value to deep copy.

Returns:

a deep copy of the given value.

createFixed

public Object createFixed(Object old,
                 Schema schema)

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

createFixed

public Object createFixed(Object old,
                 byte[] bytes,
                 Schema schema)

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

createEnum

public Object createEnum(String symbol,
                Schema schema)

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

newRecord

public Object newRecord(Object old,
               Schema schema)

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.