spi.registry.KotlinCodeGenerationServiceLoader.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of kotlin-code-generation Show documentation

Wrapping core components for kotlin code generation with kotlin-poet.

There is a newer version: 0.1.0

Show newest version

package io.toolisticon.kotlin.generation.spi.registry

import com.squareup.kotlinpoet.ExperimentalKotlinPoetApi
import io.toolisticon.kotlin.generation.KotlinCodeGeneration
import io.toolisticon.kotlin.generation.spi.KotlinCodeGenerationSpi
import io.toolisticon.kotlin.generation.spi.KotlinCodeGenerationSpiRegistry
import io.toolisticon.kotlin.generation.spi.UnboundKotlinCodeGenerationProcessor
import io.toolisticon.kotlin.generation.spi.UnboundKotlinCodeGenerationStrategy
import io.toolisticon.kotlin.generation.spi.processor.KotlinCodeGenerationProcessorList
import io.toolisticon.kotlin.generation.spi.strategy.KotlinCodeGenerationStrategyList
import java.util.ServiceLoader
import kotlin.reflect.KClass
import kotlin.reflect.full.isSubclassOf

/**
 * Provides [KotlinCodeGenerationSpiRegistry] using [ServiceLoader].
 *
 * To avoid too many ´META-INF/services` declarations, all [KotlinCodeGenerationSpi] instances are declared in
 * one single resource. The loading mechanism automatically sorts them into strategies and processors.
 */
@ExperimentalKotlinPoetApi
class KotlinCodeGenerationServiceLoader(
  val contextTypeUpperBound: KClass<*> = Any::class,
  val classLoader: ClassLoader = KotlinCodeGeneration.spi.defaultClassLoader(),
  val exclusions: Set = emptySet()
) : () -> KotlinCodeGenerationSpiRegistry {

  override fun invoke(): KotlinCodeGenerationSpiRegistry {
    val serviceInstances: List> = ServiceLoader.load(KotlinCodeGenerationSpi::class.java, classLoader).toList()
      .filterNot { exclusions.contains(it::class.java.name) }
    check(serviceInstances.isNotEmpty()) { "No serviceInstances found, configure `${KotlinCodeGenerationSpi.metaInfServices}`, and/or check your exclusions filter." }

    val withIllegalContextType = serviceInstances.filterNot { it.contextType.isSubclassOf(contextTypeUpperBound) }

    require(withIllegalContextType.isEmpty()) {
      "All declarations of type `${KotlinCodeGenerationSpi.metaInfServices}` " +
        "must be a subclass of contextType=$contextTypeUpperBound, but " +
        "found ${withIllegalContextType.joinToString(", ")}."
    }

    return KotlinCodeGenerationServiceRepository(
      contextTypeUpperBound = contextTypeUpperBound,
      strategies = KotlinCodeGenerationStrategyList(serviceInstances.filterIsInstance()),
      processors = KotlinCodeGenerationProcessorList(serviceInstances.filterIsInstance())
    )
  }
}