org.apache.beam.sdk.schemas

Class SchemaCoder<T>

java.lang.Object

org.apache.beam.sdk.coders.Coder<T>

org.apache.beam.sdk.coders.CustomCoder<T>

org.apache.beam.sdk.schemas.SchemaCoder<T>

All Implemented Interfaces:

java.io.Serializable

@Experimental(value=SCHEMAS)
public class SchemaCoder<T>
extends CustomCoder<T>

SchemaCoder is used as the coder for types that have schemas registered.

See Also:

Serialized Form

Nested Class Summary

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

Coder.Context, Coder.NonDeterministicException

Method Summary

Modifier and Type	Method and Description
boolean	consistentWithEquals() Returns true if this Coder is injective with respect to Object.equals(java.lang.Object).
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.
SerializableFunction<Row,T>	getFromRowFunction() Returns the toRow conversion function.
Schema	getSchema() Returns the schema associated with this type.
SerializableFunction<T,Row>	getToRowFunction() Returns the fromRow conversion function.
static SchemaCoder<Row>	of(Schema schema) Returns a SchemaCoder for Row classes.
static <T> SchemaCoder<T>	of(Schema schema, SerializableFunction<T,Row> toRowFunction, SerializableFunction<Row,T> fromRowFunction) Returns a SchemaCoder for the specified class.
java.lang.String	toString()
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

decode, encode, getEncodedElementByteSize, getEncodedTypeDescriptor, isRegisterByteSizeObserverCheap, registerByteSizeObserver, structuralValue, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

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

Method Detail

of

public static <T> SchemaCoder<T> of(Schema schema,
                                    SerializableFunction<T,Row> toRowFunction,
                                    SerializableFunction<Row,T> fromRowFunction)

Returns a SchemaCoder for the specified class. If no schema is registered for this class, then throws NoSuchSchemaException.

of

public static SchemaCoder<Row> of(Schema schema)

Returns a SchemaCoder for Row classes.

getSchema

public Schema getSchema()

Returns the schema associated with this type.

getFromRowFunction

public SerializableFunction<Row,T> getFromRowFunction()

Returns the toRow conversion function.

getToRowFunction

public SerializableFunction<T,Row> getToRowFunction()

Returns the fromRow conversion function.

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:

Coder.NonDeterministicException - if this coder is not deterministic.

consistentWithEquals

public boolean consistentWithEquals()

Description copied from class: Coder

Returns true if this Coder is injective with respect to Object.equals(java.lang.Object).

Whenever the encoded bytes of two values are equal, then the original values are equal according to Objects.equals(). Note that this is well-defined for null.

This condition is most notably false for arrays. More generally, this condition is false whenever equals() compares object identity, rather than performing a semantic/structural comparison.

By default, returns false.

Overrides:

consistentWithEquals in class Coder<T>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object