se.ansman.kotshi.generators.ObjectAdapterGenerator.kt Maven / Gradle / Ivy

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An annotations processor that generates Moshi adapters from Kotlin data classes

There is a newer version: 3.0.0

package se.ansman.kotshi.generators

import com.squareup.kotlinpoet.FunSpec
import com.squareup.kotlinpoet.KModifier
import com.squareup.kotlinpoet.TypeSpec
import com.squareup.kotlinpoet.jvm.throws
import com.squareup.kotlinpoet.metadata.ImmutableKmClass
import com.squareup.kotlinpoet.metadata.isObject
import com.squareup.kotlinpoet.metadata.specs.ClassInspector
import se.ansman.kotshi.addControlFlow
import se.ansman.kotshi.addElse
import se.ansman.kotshi.addIfElse
import se.ansman.kotshi.nullable
import javax.lang.model.element.TypeElement
import javax.lang.model.util.Elements
import javax.lang.model.util.Types

class ObjectAdapterGenerator(
    classInspector: ClassInspector,
    types: Types,
    elements: Elements,
    element: TypeElement,
    metadata: ImmutableKmClass,
    globalConfig: GlobalConfig
) : AdapterGenerator(classInspector, types, elements, element, metadata, globalConfig) {
    init {
        require(metadata.isObject)
    }

    override fun TypeSpec.Builder.addMethods() {
        this
            .addFunction(FunSpec.builder("toJson")
                .addModifiers(KModifier.OVERRIDE)
                .throws(ioException)
                .addParameter(writerParameter)
                .addParameter(value)
                .addIfElse("%N == null", value) {
                    addStatement("%N.nullValue()", writerParameter)
                }
                .addElse {
                    addStatement("%N.beginObject()", writerParameter)
                    for ((key, value) in getPolymorphicLabels()) {
                        addStatement("%N.name(%S).value(%S)", writerParameter, key, value)
                    }
                    addStatement("%N.endObject()", writerParameter)
                }
                .build())
            .addFunction(FunSpec.builder("fromJson")
                .addModifiers(KModifier.OVERRIDE)
                .throws(ioException)
                .addParameter(readerParameter)
                .returns(typeName.nullable())
                .addControlFlow("return when·(%N.peek())", readerParameter) {
                    addStatement("%T.NULL·-> %N.nextNull()", jsonReaderToken, readerParameter)
                    addControlFlow("%T.BEGIN_OBJECT·->", jsonReaderToken) {
                        addStatement("%N.skipValue()", readerParameter)
                        addStatement("%T", typeName)
                    }
                    addStatement("else·-> throw·%T(%P)", jsonDataException, "Expected BEGIN_OBJECT but was \${${readerParameter.name}.peek()} at path \${${readerParameter.name}.path}")
                }
                .build())
    }
}