org.apache.beam.sdk.coders

Class StringUtf8Coder

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.String>

org.apache.beam.sdk.coders.StringUtf8Coder

All Implemented Interfaces:

java.io.Serializable

public class StringUtf8Coder
extends AtomicCoder<java.lang.String>

A Coder that encodes Strings in UTF-8 encoding. If in a nested context, prefixes the string with an integer length field, 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
boolean	consistentWithEquals() Returns true if this Coder is injective with respect to Object.equals(java.lang.Object).
java.lang.String	decode(java.io.InputStream inStream) Decodes a value of type T from the given input stream in the given context.
java.lang.String	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(java.lang.String value, java.io.OutputStream outStream) Encodes the given value of type T onto the given output stream.
void	encode(java.lang.String value, java.io.OutputStream outStream, Coder.Context context) Encodes the given value of type T onto the given output stream in the given context.
long	getEncodedElementByteSize(java.lang.String value) Returns the size in bytes of the encoded value using this coder.
TypeDescriptor<java.lang.String>	getEncodedTypeDescriptor() Returns the TypeDescriptor for the type encoded.
static StringUtf8Coder	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

isRegisterByteSizeObserverCheap, registerByteSizeObserver, structuralValue, verifyDeterministic, verifyDeterministic

Methods inherited from class java.lang.Object

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

Method Detail

of

public static StringUtf8Coder of()

encode

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

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(java.lang.String value,
                   java.io.OutputStream outStream,
                   Coder.Context context)
            throws java.io.IOException

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<java.lang.String>

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.String 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<java.lang.String>

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 java.lang.String decode(java.io.InputStream inStream,
                               Coder.Context context)
                        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.

Overrides:

decode in class Coder<java.lang.String>

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()

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<java.lang.String>

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.String>

Returns:

true. This coder is injective.

getEncodedTypeDescriptor

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

Description copied from class: Coder

Returns the TypeDescriptor for the type encoded.

Overrides:

getEncodedTypeDescriptor in class Coder<java.lang.String>

getEncodedElementByteSize

public long getEncodedElementByteSize(java.lang.String value)
                               throws java.lang.Exception

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

Overrides:

getEncodedElementByteSize in class Coder<java.lang.String>

Returns:

the byte size of the UTF-8 encoding of the a string or, in a nested context, the byte size of the encoding plus the encoded length prefix.

Throws:

java.lang.Exception