AvroCoder (Apache Beam 2.7.0)

java.lang.Object
- org.apache.beam.sdk.coders.Coder<T>
- - org.apache.beam.sdk.coders.CustomCoder<T>
  - - org.apache.beam.sdk.coders.AvroCoder<T>

Type Parameters:

T - the type of elements handled by this coder

All Implemented Interfaces:

java.io.Serializable
```
public class AvroCoder<T>
extends CustomCoder<T>
```
A Coder using Avro binary format.
Each instance of AvroCoder<T> encapsulates an Avro schema for objects of type T.
The Avro schema may be provided explicitly via of(Class, Schema) or omitted via of(Class), in which case it will be inferred using Avro's ReflectData.
For complete details about schema generation and how it can be controlled please see the org.apache.avro.reflect package. Only concrete classes with a no-argument constructor can be mapped to Avro records. All inherited fields that are not static or transient are included. Fields are not permitted to be null unless annotated by Nullable or a Union schema containing "null".
To use, specify the Coder type on a PCollection:
```
 PCollection<MyCustomElement> records =
     input.apply(...)
          .setCoder(AvroCoder.of(MyCustomElement.class);
 
```
or annotate the element class using @DefaultCoder.
```
  @DefaultCoder(AvroCoder.class)
 public class MyCustomElement {
   ...
 }
 
```
The implementation attempts to determine if the Avro encoding of the given type will satisfy the criteria of Coder.verifyDeterministic() by inspecting both the type and the Schema provided or generated by Avro. Only coders that are deterministic can be used in GroupByKey operations.
See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.beam.sdk.coders.Coder
  Coder.Context, Coder.NonDeterministicException

Constructor Summary

Constructors
Modifier Constructor and Description

protected AvroCoder(java.lang.Class<T> type, Schema schema)

Constructors
Modifier	Constructor and Description
`protected`	`AvroCoder(java.lang.Class<T> type, Schema schema)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`T`	`decode(java.io.InputStream inStream)` Decodes a value of type `T` from the given input stream in the given context.
`void`	`encode(T value, java.io.OutputStream outStream)` Encodes the given value of type `T` onto the given output stream.
`boolean`	`equals(java.lang.Object other)`
`static CoderProvider`	`getCoderProvider()` Returns a `CoderProvider` which uses the `AvroCoder` if possible for all types.
`TypeDescriptor<T>`	`getEncodedTypeDescriptor()` Returns the `TypeDescriptor` for the type encoded.
`Schema`	`getSchema()` Returns the schema used by this coder.
`java.lang.Class<T>`	`getType()` Returns the type this coder encodes/decodes.
`int`	`hashCode()`
`static <T> AvroCoder<T>`	`of(java.lang.Class<T> clazz)` Returns an `AvroCoder` instance for the provided element class.
`static <T> AvroCoder<T>`	`of(java.lang.Class<T> type, Schema schema)` Returns an `AvroCoder` instance for the provided element type using the provided Avro schema.
`static AvroCoder<GenericRecord>`	`of(Schema schema)` Returns an `AvroCoder` instance for the Avro schema.
`static <T> AvroCoder<T>`	`of(TypeDescriptor<T> type)` Returns an `AvroCoder` instance for the provided element type.
`void`	`verifyDeterministic()` Throw `Coder.NonDeterministicException` if the coding is not deterministic.

Methods inherited from class org.apache.beam.sdk.coders.CustomCoder
getCoderArguments

Methods inherited from class org.apache.beam.sdk.coders.Coder
consistentWithEquals, decode, encode, getEncodedElementByteSize, isRegisterByteSizeObserverCheap, registerByteSizeObserver, structuralValue, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - AvroCoder
```
protected AvroCoder(java.lang.Class<T> type,
                    Schema schema)
```
- Method Detail
  - of
```
public static <T> AvroCoder<T> of(TypeDescriptor<T> type)
```
    Returns an AvroCoder instance for the provided element type.
    
    Type Parameters:
    
    T - the element type
  - of
```
public static <T> AvroCoder<T> of(java.lang.Class<T> clazz)
```
    Returns an AvroCoder instance for the provided element class.
    
    Type Parameters:
    
    T - the element type
  - of
```
public static AvroCoder<GenericRecord> of(Schema schema)
```
    Returns an AvroCoder instance for the Avro schema. The implicit type is GenericRecord.
  - of
```
public static <T> AvroCoder<T> of(java.lang.Class<T> type,
                                  Schema schema)
```
    Returns an AvroCoder instance for the provided element type using the provided Avro schema.
    If the type argument is GenericRecord, the schema may be arbitrary. Otherwise, the schema must correspond to the type provided.
    
    Type Parameters:
    
    T - the element type
  - getCoderProvider
```
public static CoderProvider getCoderProvider()
```
    Returns a CoderProvider which uses the AvroCoder if possible for all types.
    It is unsafe to register this as a CoderProvider because Avro will reflectively accept dangerous types such as Object.
    This method is invoked reflectively from DefaultCoder.
  - getType
```
public java.lang.Class<T> getType()
```
    Returns the type this coder encodes/decodes.
  - encode
```
public void encode(T value,
                   java.io.OutputStream outStream)
            throws java.io.IOException
```
    Description copied from class: Coder
    
    Encodes the given value of type T onto the given output stream.
    
    Specified by:
    
    encode in class Coder<T>
    
    Throws:
    
    java.io.IOException - if writing to the OutputStream fails for some reason
    
    CoderException - if the value could not be encoded for some reason
  - decode
```
public T decode(java.io.InputStream inStream)
         throws java.io.IOException
```
    Description copied from class: Coder
    
    Decodes a value of type T from the given input stream in the given context. Returns the decoded value.
    
    Specified by:
    
    decode in class Coder<T>
    
    Throws:
    
    java.io.IOException - if reading from the InputStream fails for some reason
    
    CoderException - if the value could not be decoded for some reason
  - verifyDeterministic
```
public void verifyDeterministic()
                         throws Coder.NonDeterministicException
```
    Description copied from class: CustomCoder
    Throw Coder.NonDeterministicException if the coding is not deterministic.
    In order for a Coder to be considered deterministic, the following must be true:
    - two values that compare as equal (via Object.equals() or Comparable.compareTo(), if supported) have the same encoding.
    - the Coder always produces a canonical encoding, which is the same for an instance of an object even if produced on different computers at different times.
    Overrides:
    
    verifyDeterministic in class CustomCoder<T>
    
    Throws:
    
    NonDeterministicException - when the type may not be deterministically encoded using the given Schema, the directBinaryEncoder, and the ReflectDatumWriter or GenericDatumWriter.
    
    Coder.NonDeterministicException - if this coder is not deterministic.
  - getSchema
```
public Schema getSchema()
```
    Returns the schema used by this coder.
  - getEncodedTypeDescriptor
```
public TypeDescriptor<T> getEncodedTypeDescriptor()
```
    Description copied from class: Coder
    
    Returns the TypeDescriptor for the type encoded.
    
    Overrides:
    
    getEncodedTypeDescriptor in class Coder<T>
  - equals
```
public boolean equals(java.lang.Object other)
```
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object

Class AvroCoder<T>

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.beam.sdk.coders.Coder

Constructor Summary

Method Summary

Methods inherited from class org.apache.beam.sdk.coders.CustomCoder

Methods inherited from class org.apache.beam.sdk.coders.Coder

Methods inherited from class java.lang.Object

Constructor Detail

AvroCoder

Method Detail

of

of

of

of

getCoderProvider

getType

encode

decode

verifyDeterministic

getSchema

getEncodedTypeDescriptor

equals

hashCode