org.apache.beam.sdk.coders

Class ByteArrayCoder

java.lang.Object

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

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

org.apache.beam.sdk.coders.AtomicCoder<byte[]>

org.apache.beam.sdk.coders.ByteArrayCoder

All Implemented Interfaces:

java.io.Serializable

public class ByteArrayCoder
extends AtomicCoder<byte[]>

A Coder for byte[].

The encoding format is as follows:

• If in a non-nested context (the byte[] is the only value in the stream), the bytes are read/written directly.
• If in a nested context, the bytes are prefixed with the length of the array, encoded via a VarIntCoder.

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
byte[]	decode(java.io.InputStream inStream) Decodes a value of type T from the given input stream in the given context.
byte[]	decode(java.io.InputStream inStream, Coder.Context context) Decodes a value of type T from the given input stream in the given context.
void	encode(byte[] value, java.io.OutputStream outStream) Encodes the given value of type T onto the given output stream.
void	encode(byte[] value, java.io.OutputStream outStream, Coder.Context context) Encodes the given value of type T onto the given output stream in the given context.
void	encodeAndOwn(byte[] value, java.io.OutputStream outStream, Coder.Context context) Encodes the provided value with the identical encoding to encode(byte[], java.io.OutputStream), but with optimizations that take ownership of the value.
java.util.List<? extends Coder<?>>	getCoderArguments() If this is a Coder for a parameterized type, returns the list of Coders being used for each of the parameters in the same order they appear within the parameterized type's type signature.
protected long	getEncodedElementByteSize(byte[] value) Returns the size in bytes of the encoded value using this coder.
TypeDescriptor<byte[]>	getEncodedTypeDescriptor() Returns the TypeDescriptor for the type encoded.
boolean	isRegisterByteSizeObserverCheap(byte[] value) Returns whether Coder.registerByteSizeObserver(T, org.apache.beam.sdk.util.common.ElementByteSizeObserver) cheap enough to call for every element, that is, if this Coder can calculate the byte size of the element to be coded in roughly constant time (or lazily).
static ByteArrayCoder	of()
java.lang.Object	structuralValue(byte[] value) Returns an object with an Object.equals() method that represents structural equality on the argument.
void	verifyDeterministic() Throw Coder.NonDeterministicException if the coding is not deterministic.

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

equals, getComponents, hashCode

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

consistentWithEquals, toString

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

registerByteSizeObserver, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

of

public static ByteArrayCoder of()

encode

public void encode(byte[] value,
                   java.io.OutputStream outStream)
            throws java.io.IOException,
                   CoderException

Description copied from class: Coder

Encodes the given value of type T onto the given output stream.

Specified by:

encode in class Coder<byte[]>

Throws:

java.io.IOException - if writing to the OutputStream fails for some reason

CoderException - if the value could not be encoded for some reason

encode

public void encode(byte[] value,
                   java.io.OutputStream outStream,
                   Coder.Context context)
            throws java.io.IOException,
                   CoderException

Description copied from class: Coder

Encodes the given value of type T onto the given output stream in the given context.

Overrides:

encode in class Coder<byte[]>

Throws:

java.io.IOException - if writing to the OutputStream fails for some reason

CoderException - if the value could not be encoded for some reason

encodeAndOwn

public void encodeAndOwn(byte[] value,
                         java.io.OutputStream outStream,
                         Coder.Context context)
                  throws java.io.IOException,
                         CoderException

Encodes the provided value with the identical encoding to encode(byte[], java.io.OutputStream), but with optimizations that take ownership of the value.

Once passed to this method, value should never be observed or mutated again.

Throws:

java.io.IOException

CoderException

decode

public byte[] decode(java.io.InputStream inStream)
              throws java.io.IOException,
                     CoderException

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<byte[]>

Throws:

java.io.IOException - if reading from the InputStream fails for some reason

CoderException - if the value could not be decoded for some reason

decode

public byte[] decode(java.io.InputStream inStream,
                     Coder.Context context)
              throws java.io.IOException,
                     CoderException

Description copied from class: Coder

Decodes a value of type T from the given input stream in the given context. Returns the decoded value.

Overrides:

decode in class Coder<byte[]>

Throws:

java.io.IOException - if reading from the InputStream fails for some reason

CoderException - if the value could not be decoded for some reason

getCoderArguments

public java.util.List<? extends Coder<?>> getCoderArguments()

Description copied from class: AtomicCoder

If this is a Coder for a parameterized type, returns the list of Coders being used for each of the parameters in the same order they appear within the parameterized type's type signature. If this cannot be done, or this Coder does not encode/decode a parameterized type, returns the empty list..

Overrides:

getCoderArguments in class AtomicCoder<byte[]>

Returns:

the empty list

verifyDeterministic

public void verifyDeterministic()

Description copied from class: AtomicCoder

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.

.

Unless overridden, does not throw. An AtomicCoder is presumed to be deterministic

Overrides:

verifyDeterministic in class AtomicCoder<byte[]>

structuralValue

public java.lang.Object structuralValue(byte[] value)

Returns an object with an Object.equals() method that represents structural equality on the argument.

For any two values x and y of type T, if their encoded bytes are the same, then it must be the case that structuralValue(x).equals(@code structuralValue(y).

Most notably:

• The structural value for an array coder should perform a structural comparison of the contents of the arrays, rather than the default behavior of comparing according to object identity.
• The structural value for a coder accepting null should be a proper object with an equals() method, even if the input value is null.

See also Coder.consistentWithEquals().

By default, if this coder is Coder.consistentWithEquals(), and the value is not null, returns the provided object. Otherwise, encodes the value into a byte[], and returns an object that performs array equality on the encoded bytes.

Overrides:

structuralValue in class StructuredCoder<byte[]>

Returns:

objects that are equal if the two arrays contain the same bytes.

isRegisterByteSizeObserverCheap

public boolean isRegisterByteSizeObserverCheap(byte[] value)

Returns whether Coder.registerByteSizeObserver(T, org.apache.beam.sdk.util.common.ElementByteSizeObserver) cheap enough to call for every element, that is, if this Coder can calculate the byte size of the element to be coded in roughly constant time (or lazily).

Not intended to be called by user code, but instead by PipelineRunner implementations.

By default, returns false. The default Coder.registerByteSizeObserver(T, org.apache.beam.sdk.util.common.ElementByteSizeObserver) implementation invokes Coder.getEncodedElementByteSize(T) which requires re-encoding an element unless it is overridden. This is considered expensive.

Overrides:

isRegisterByteSizeObserverCheap in class Coder<byte[]>

Returns:

true since getEncodedElementByteSize(byte[]) runs in constant time using the length of the provided array.

getEncodedTypeDescriptor

public TypeDescriptor<byte[]> getEncodedTypeDescriptor()

Description copied from class: Coder

Returns the TypeDescriptor for the type encoded.

Overrides:

getEncodedTypeDescriptor in class StructuredCoder<byte[]>

getEncodedElementByteSize

protected long getEncodedElementByteSize(byte[] value)
                                  throws java.lang.Exception

Description copied from class: Coder

Returns the size in bytes of the encoded value using this coder.

Overrides:

getEncodedElementByteSize in class Coder<byte[]>

Throws:

java.lang.Exception