com.sksamuel.avro4s.SchemaFor.scala Maven / Gradle / Ivy

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package com.sksamuel.avro4s

import com.sksamuel.avro4s.avroutils.SchemaHelper
import com.sksamuel.avro4s.schemas.{ByteIterableSchemas, CollectionSchemas, EitherSchemas, EnumSchemas, MagnoliaDerivedSchemas, OptionSchemas, PrimitiveSchemas, StringSchemas, TemporalSchemas, TupleSchemas}
import org.apache.avro.util.Utf8
import org.apache.avro.{LogicalType, LogicalTypes, Schema, SchemaBuilder}

import java.nio.ByteBuffer
import java.sql.Timestamp
import java.time.{Instant, LocalDate, LocalDateTime, OffsetDateTime}
import java.util.{Date, UUID}

/**
  * A [[SchemaFor]] generates an Avro Schema for a Scala or Java type.
  *
  * For example, a SchemaFor[String] could return a schema of type Schema.Type.STRING, and
  * a SchemaFor[Int] could return an schema of type Schema.Type.INT
  */
trait SchemaFor[T] {
  self =>

  /**
    * Returns the avro [[Schema]] generated by this typeclass, applying the given [[FieldMapper]]
    * to each field of record types.
    */
  def schema: Schema

  /**
    * Applies a [[FieldMapper]] to this typeclass, so that the returned schema has any
    * fields transformed by the mapper.
    */
  final def withFieldMapper(mapper: FieldMapper): SchemaFor[T] = new SchemaFor[T] {
    lazy val mapped = SchemaHelper.mapNames(self.schema, mapper)
    override def schema = mapped
  }

  /**
    * Changes the type of this SchemaFor to the desired type `U` without any other modifications.
    *
    * @tparam U new type for SchemaFor.
    */
  final def forType[U]: SchemaFor[U] = map[U](identity)

  /**
    * Creates a SchemaFor[U] by applying a function Schema => Schema
    * to the schema generated by this instance.
    */
  final def map[U](fn: Schema => Schema): SchemaFor[U] = {
    return new SchemaFor[U] {
      override def schema = fn(self.schema)
    }
  }
}

object SchemaFor
  extends PrimitiveSchemas
    with BigDecimalSchemas
    with ByteIterableSchemas
    with CollectionSchemas
    with EitherSchemas
    with EnumSchemas
    with OptionSchemas
    with StringSchemas
    with TemporalSchemas
    with TupleSchemas
    with MagnoliaDerivedSchemas {

  /**
    * Returns a [[SchemaFor]] that returns the given schema.
    */
  def apply[T](s: Schema): SchemaFor[T] = new SchemaFor[T] {
    override def schema: Schema = s
  }

  def from[T](f: => Schema): SchemaFor[T] = new SchemaFor[T] {
    override def schema: Schema = f
  }

  def apply[T](using schemaFor: SchemaFor[T]): SchemaFor[T] = schemaFor
}