ZstdCoder (Apache Beam 2.57.0)

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

All Implemented Interfaces:

java.io.Serializable
```
public class ZstdCoder<T>
extends Coder<T>
```
Wraps an existing coder with Zstandard compression. It makes sense to use this coder when it's likely that the encoded value is quite large and compressible or when a dictionary is available to improve compression performance.
This coder uses the Zstandard compression library's direct compression methods (from byte[] to byte[]) and thus requires that the inner coder's encoded value must fit in a byte[].

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

All Methods Static Methods Instance Methods Concrete Methods
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 is)` Decodes a value of type `T` from the given input stream in the given context.
`void`	`encode(T value, java.io.OutputStream os)` Encodes the given value of type `T` onto the given output stream.
`boolean`	`equals(java.lang.Object o)`
`java.util.List<? extends Coder<?>>`	`getCoderArguments()` If this is a `Coder` for a parameterized type, returns the list of `Coder`s being used for each of the parameters in the same order they appear within the parameterized type's type signature.
`int`	`hashCode()`
`static <T> ZstdCoder<T>`	`of(Coder<T> innerCoder)` Wraps the given coder into a `ZstdCoder`.
`static <T> ZstdCoder<T>`	`of(Coder<T> innerCoder, byte[] dict)` Wraps the given coder into a `ZstdCoder`.
`static <T> ZstdCoder<T>`	`of(Coder<T> innerCoder, byte[] dict, int level)` Wraps the given coder into a `ZstdCoder`.
`static <T> ZstdCoder<T>`	`of(Coder<T> innerCoder, int level)` Wraps the given coder into a `ZstdCoder`.
`java.lang.Object`	`structuralValue(T value)` Returns an object with an `Object.equals()` method that represents structural equality on the argument.
`java.lang.String`	`toString()`
`void`	`verifyDeterministic()` Throw `Coder.NonDeterministicException` if the coding is not deterministic.

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

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

- Method Detail
  - of
```
public static <T> ZstdCoder<T> of(Coder<T> innerCoder,
                                  byte[] dict,
                                  int level)
```
    Wraps the given coder into a ZstdCoder.
  - of
```
public static <T> ZstdCoder<T> of(Coder<T> innerCoder,
                                  byte[] dict)
```
    Wraps the given coder into a ZstdCoder.
  - of
```
public static <T> ZstdCoder<T> of(Coder<T> innerCoder,
                                  int level)
```
    Wraps the given coder into a ZstdCoder.
  - of
```
public static <T> ZstdCoder<T> of(Coder<T> innerCoder)
```
    Wraps the given coder into a ZstdCoder.
  - encode
```
public void encode(T value,
                   java.io.OutputStream os)
            throws java.io.IOException
```
    Description copied from class: Coder
    
    Encodes the given value of type T onto the given output stream. Multiple elements can be encoded next to each other on the output stream, each coder should encode information to know how many bytes to read when decoding. A common approach is to prefix the encoding with the element's encoded length.
    
    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 is)
         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. Multiple elements can be encoded next to each other on the input stream, each coder should encode information to know how many bytes to read when decoding. A common approach is to prefix the encoding with the element's encoded length.
    
    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
  - getCoderArguments
```
public java.util.List<? extends Coder<?>> getCoderArguments()
```
    Description copied from class: Coder
    
    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.
    
    Specified by:
    
    getCoderArguments in class Coder<T>
  - 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.
    ZstdCoder is deterministic if the inner coder is deterministic.
    Specified by:
    
    verifyDeterministic in class Coder<T>
    
    Throws:
    
    Coder.NonDeterministicException - if this coder is not deterministic.
  - 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.
    ZstdCoder is consistent with equals if the inner coder is consistent with equals.
    
    Overrides:
    
    consistentWithEquals in class Coder<T>
    
    Returns:
    
    The same value as the inner coder.
  - structuralValue
```
public java.lang.Object structuralValue(T 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(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.
    ZstdCoder uses the structural value of the inner coder.
    Overrides:
    
    structuralValue in class Coder<T>
    
    Returns:
    
    The structural value of the inner coder.
  - equals
```
public boolean equals(@Nullable
                      java.lang.Object o)
```
    Overrides:
    
    equals in class java.lang.Object
    
    Returns:
    
    true if the two ZstdCoder instances have the same class, inner coder, dictionary and compression level.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class ZstdCoder<T>

Nested Class Summary

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

Method Summary

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

Methods inherited from class java.lang.Object

Method Detail

of

of

of

of

encode

decode

getCoderArguments

verifyDeterministic

consistentWithEquals

structuralValue

equals

hashCode

toString