README.md

Baleen Poet

Baleen Poet is an extension of the awesome KotlinPoet library that supports writing Kotlin files. This library takes a BaleenType as input and then writes it to the file. This is especially useful for Baleen generators where an external format like Json schema or Avro schemas can be imported to create a Baleen schema.

Installation

Gradle

implementation("com.shoprunner:baleen-poet:$baleen_version")

Examples

Simple Baleen Types write to a file with no package.

import com.shoprunner.baleen.poet.toFileSpec
import com.shoprunner.baleen.types.BooleanType

val booleanTest = BooleanType()

booleanTest.toFileSpec().writeTo(File("src/"))

Creates src/boolean.kt

import com.shoprunner.baleen.BaleenType
import com.shoprunner.baleen.types.BooleanType

val boolean: BaleenType = BooleanType()

Setting the name and package can customize where the file gets written

import com.shoprunner.baleen.poet.toFileSpec
import com.shoprunner.baleen.types.BooleanType

val booleanTest = BooleanType()

booleanTest.toFileSpec("com.shoprunner.baleen.test", "MyBooleanType").writeTo(File("src/"))

Creates src/com/shoprunner/baleen/test/MyBooleanType.kt

package com.shoprunner.baleen.test

import com.shoprunner.baleen.BaleenType
import com.shoprunner.baleen.types.BooleanType

val MyBooleanType: BaleenType = BooleanType()

A DataDescription can be written to the file based off the Description name and namespace (if present).

import com.shoprunner.baleen.describeAs
import com.shoprunner.baleen.poet.toFileSpec
import com.shoprunner.baleen.types.AllowsNull
import com.shoprunner.baleen.types.IntType
import com.shoprunner.baleen.types.StringType

val type = "Dog".describeAs("com.shoprunner.baleen.test") {
    "name".type(StringType())
    "numLegs".type(AllowsNull(IntType()))
}

type.toFileSpec().writeTo(File("src/"))

Creates src/com/shoprunner/baleen/test/Dog.kt

package com.shoprunner.baleen.poet.test

import com.shoprunner.baleen.Baleen.describe
import com.shoprunner.baleen.DataDescription
import com.shoprunner.baleen.types.AllowsNull
import com.shoprunner.baleen.types.IntType
import com.shoprunner.baleen.types.StringType

val Dog: DataDescription = describe("Dog", "com.shoprunner.baleen.poet.test", "") {
      it.attr(
        name = "name",
        type = StringType(min = 0, max = Int.MAX_VALUE)
      )
      it.attr(
        name = "numLegs",
        type = AllowsNull(IntType(min = Int.MIN_VALUE, max = Int.MAX_VALUE))
      )

    }

Nested Baleen descriptions are written to separate source files. Use generateAllFileSpecs to generate files for all nested descriptions.

import com.shoprunner.baleen.describeAs
import com.shoprunner.baleen.poet.generateAllFileSpecs
import com.shoprunner.baleen.types.AllowsNull
import com.shoprunner.baleen.types.IntType
import com.shoprunner.baleen.types.StringType

val dog = "Dog".describeAs(nameSpace = "com.shoprunner.dog") {
    "name".type(StringType())
    "numLegs".type(AllowsNull(IntType()))
}

val pack = "Pack".describeAs(nameSpace = "com.shoprunner.pack") {
    "dogs".type(OccurrencesType(dog))
}

pack.generateAllFileSpecs().forEach { it.writeTo(File("src/")) }

Generates 2 source files

src/com/shoprunner/dog/Dog.kt

package com.shoprunner.dog

import com.shoprunner.baleen.Baleen.describe
import com.shoprunner.baleen.DataDescription
import com.shoprunner.baleen.types.AllowsNull
import com.shoprunner.baleen.types.IntType
import com.shoprunner.baleen.types.StringType

val Dog: DataDescription = describe("NestedDog", "com.shoprunner.dog", "") {
      it.attr(
        name = "name",
        type = StringType(min = 0, max = Int.MAX_VALUE)
      )
      it.attr(
        name = "numLegs",
        type = AllowsNull(IntType(min = Int.MIN_VALUE, max = Int.MAX_VALUE))
      )

    }

src/com/shoprunner/pack/Pack.kt

package com.shoprunner.pack

import com.shoprunner.baleen.Baleen.describe
import com.shoprunner.baleen.DataDescription
import com.shoprunner.baleen.types.OccurrencesType
import com.shoprunner.dog.Dog

val Pack: DataDescription = describe("Pack", "com.shoprunner.pack", "") {
      it.attr(
        name = "dogs",
        type = OccurrencesType(Dog)
      )

    }

Types can be overridden using a TypeMapper function. It takes the CodeBlock.Builder and BaleenType and allows for customized code for BaleenTypes that need to be overriden or do not have mapping in the default type mapper.

typealias TypeMapper = (CodeBlock.Builder, BaleenType) -> CodeBlock.Builder

fun customOverride(builder: CodeBlock.Builder, baleenType: BaleenType): CodeBlock.Builder =
    when {
        baleenType is StringType -> builder.add("%T()", IntType::class)
        baleenType is DataDescription && baleenType.name == "Dog" -> builder.add("%T()", StringType::class) 
        else -> defaultTypeMapper(builder, baleenType, ::customOverride) // Recursive call here
    }

val spec = type.toFileSpec(typeMapper = ::customOverride)
spec.writeTo(File("src/"))