Package io.bytestreams.codec.core

Class ChoiceCodec<V>

java.lang.Object

io.bytestreams.codec.core.ChoiceCodec<V>

Type Parameters:

V - the base type of the discriminated union

All Implemented Interfaces:

Codec<V>, Inspectable<V>

public class ChoiceCodec<V>
extends Object
implements Codec<V>, Inspectable<V>

A codec for discriminated unions where a class tag determines which codec to use for the value.

The wire format is [tag][value], where the tag selects among registered alternatives. This codec only sees Codec<Class<? extends V>> — callers typically create it by using xmap(Converter) to map a tag codec to class values:

 BiMap<Integer, Class<? extends Shape>> tags = BiMap.of(
     Map.entry(1, Circle.class),
     Map.entry(2, Rectangle.class));

 Codec<Shape> codec = Codecs.<Shape>choice(Codecs.uint8().xmap(tags))
     .on(Circle.class, circleCodec)
     .on(Rectangle.class, rectangleCodec)
     .build();
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ChoiceCodec.Builder<V>	Builder for ChoiceCodec.

Method Summary

Modifier and Type	Method	Description
V	decode(InputStream input)	Decodes a value from the input stream.
EncodeResult	encode(V value, OutputStream output)	Encodes the given value and writes it to the output stream.
Object	inspect(V value)	Returns a structured representation of the given value.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.bytestreams.codec.core.Codec

xmap, xmap

Method Details

encode

public EncodeResult encode(V value,
 OutputStream output)
                    throws IOException

Description copied from interface: Codec

Encodes the given value and writes it to the output stream.

Specified by:

encode in interface Codec<V>

Parameters:

value - the value to encode

output - the output stream to write the encoded bytes to

Returns:

the encode result containing logical count and bytes written

Throws:

IOException - if an I/O error occurs during encoding

decode

public V decode(InputStream input)
         throws IOException

Description copied from interface: Codec

Decodes a value from the input stream.

Specified by:

decode in interface Codec<V>

Parameters:

input - the input stream to read the encoded bytes from

Returns:

the decoded value

Throws:

IOException - if an I/O error occurs during decoding

inspect

public Object inspect(V value)

Description copied from interface: Inspectable

Returns a structured representation of the given value.

Specified by:

inspect in interface Inspectable<V>

Parameters:

value - the decoded value to inspect

Returns:

a structured representation (Map, List, or scalar)