Package org.apache.beam.sdk.coders

Class DoubleCoder

java.lang.Object

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

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

org.apache.beam.sdk.coders.AtomicCoder<java.lang.Double>

org.apache.beam.sdk.coders.DoubleCoder

All Implemented Interfaces:

java.io.Serializable

public class DoubleCoder
extends AtomicCoder<java.lang.Double>

A DoubleCoder encodes Double values in 8 bytes using Java serialization.

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	Description
boolean	consistentWithEquals()	Returns true if this Coder is injective with respect to Object.equals(java.lang.Object).
java.lang.Double	decode(java.io.InputStream inStream)	Decodes a value of type T from the given input stream in the given context.
void	encode(java.lang.Double value, java.io.OutputStream outStream)	Encodes the given value of type T onto the given output stream.
protected long	getEncodedElementByteSize(java.lang.Double value)	Returns the size in bytes of the encoded value using this coder.
TypeDescriptor<java.lang.Double>	getEncodedTypeDescriptor()	Returns the TypeDescriptor for the type encoded.
boolean	isRegisterByteSizeObserverCheap(java.lang.Double 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 DoubleCoder	of()
void	verifyDeterministic()	Throw Coder.NonDeterministicException if the coding is not deterministic.

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

equals, getCoderArguments, getComponents, hashCode

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

toString

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

decode, encode, registerByteSizeObserver, structuralValue, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

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

Method Detail

of

public static DoubleCoder of()

encode

public void encode(java.lang.Double 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<java.lang.Double>

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 java.lang.Double 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<java.lang.Double>

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

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<java.lang.Double>

Throws:

Coder.NonDeterministicException - always. Floating-point operations are not guaranteed to be deterministic, even if the storage format might be, so floating point representations are not recommended for use in operations that require deterministic inputs.

consistentWithEquals

public boolean consistentWithEquals()

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<java.lang.Double>

Returns:

true. This coder is injective.

isRegisterByteSizeObserverCheap

public boolean isRegisterByteSizeObserverCheap(java.lang.Double 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<java.lang.Double>

Returns:

true. getEncodedElementByteSize(java.lang.Double) returns a constant.

getEncodedTypeDescriptor

public TypeDescriptor<java.lang.Double> getEncodedTypeDescriptor()

Description copied from class: Coder

Returns the TypeDescriptor for the type encoded.

Overrides:

getEncodedTypeDescriptor in class Coder<java.lang.Double>

getEncodedElementByteSize

protected long getEncodedElementByteSize(java.lang.Double value)
                                  throws java.lang.Exception

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

Overrides:

getEncodedElementByteSize in class Coder<java.lang.Double>

Returns:

8, the byte size of a Double encoded using Java serialization.

Throws:

java.lang.Exception