generate json converter functions for krotoDC dataclasses (#25)

* generate json converter functions for krotoDC dataclasses

* add `protobuf-java-util` dependency to README

README.md

@@ -19,6 +19,7 @@ In your project's `build.gradle.kts` file, add the following dependencies:
 ```kotlin
 dependencies {
     implementation("com.google.protobuf:protobuf-java:3.25.3")
+    implementation("com.google.protobuf:protobuf-java-util:3.25.3")
     implementation("io.grpc:grpc-stub:1.61.1")
     implementation("io.grpc:grpc-kotlin-stub:1.4.1")
     implementation("io.github.mscheong01:krotoDC-core:1.0.7")

generator/build.gradle.kts

@@ -17,6 +17,7 @@ dependencies {
 //    implementation("io.grpc:grpc-protobuf:${rootProject.ext["grpcJavaVersion"]}")
     // https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java
     implementation("com.google.protobuf:protobuf-java:${rootProject.ext["protobufVersion"]}")
+    implementation("com.google.protobuf:protobuf-java-util:${rootProject.ext["protobufVersion"]}")
 
     implementation(kotlin("reflect"))
     implementation("com.squareup:kotlinpoet:${rootProject.ext["kotlinPoetVersion"]}")

generator/src/main/kotlin/io/github/mscheong01/krotodc/specgenerators/file/ConverterGenerator.kt

@@ -19,8 +19,10 @@ import com.squareup.kotlinpoet.FunSpec
 import io.github.mscheong01.krotodc.import.FunSpecsWithImports
 import io.github.mscheong01.krotodc.import.Import
 import io.github.mscheong01.krotodc.specgenerators.FileSpecGenerator
+import io.github.mscheong01.krotodc.specgenerators.function.FromJsonFunctionGenerator
 import io.github.mscheong01.krotodc.specgenerators.function.MessageToDataClassFunctionGenerator
 import io.github.mscheong01.krotodc.specgenerators.function.MessageToProtoFunctionGenerator
+import io.github.mscheong01.krotodc.specgenerators.function.ToJsonFunctionGenerator
 import io.github.mscheong01.krotodc.util.addAllImports
 import io.github.mscheong01.krotodc.util.isPredefinedType
 import io.github.mscheong01.krotodc.util.krotoDCPackage
@@ -29,6 +31,8 @@ class ConverterGenerator : FileSpecGenerator {
 
     val messageToDataClassGenerator = MessageToDataClassFunctionGenerator()
     val messageToProtoGenerator = MessageToProtoFunctionGenerator()
+    val toJsonFunctionGenerator = ToJsonFunctionGenerator()
+    val fromJsonFunctionGenerator = FromJsonFunctionGenerator()
 
     override fun generate(fileDescriptor: Descriptors.FileDescriptor): List<FileSpec> {
         val fileSpecs = mutableMapOf<String, FileSpec>()
@@ -64,6 +68,15 @@ class ConverterGenerator : FileSpecGenerator {
             funSpecs.addAll(it.funSpecs)
             imports.addAll(it.imports)
         }
+        toJsonFunctionGenerator.generate(messageDescriptor).let {
+            funSpecs.addAll(it.funSpecs)
+            imports.addAll(it.imports)
+        }
+        fromJsonFunctionGenerator.generate(messageDescriptor).let {
+            funSpecs.addAll(it.funSpecs)
+            imports.addAll(it.imports)
+        }
+
         messageDescriptor.nestedTypes.forEach { nestedType ->
             generateConvertersForMessageDescriptor(nestedType).let {
                 funSpecs.addAll(it.funSpecs)

generator/src/main/kotlin/io/github/mscheong01/krotodc/specgenerators/file/DataClassGenerator.kt

@@ -205,6 +205,8 @@ class DataClassGenerator : FileSpecGenerator {
                 .addMember("forProto = %L::class", messageDescriptor.protobufJavaTypeName)
                 .build()
         )
+
+        dataClassBuilder.addType(TypeSpec.companionObjectBuilder().build())
         return TypeSpecsWithImports(
             listOf(dataClassBuilder.build()),
             imports

generator/src/main/kotlin/io/github/mscheong01/krotodc/specgenerators/function/FromJsonFunctionGenerator.kt

@@ -0,0 +1,53 @@
+// Copyright 2024 Minsoo Cheong
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package io.github.mscheong01.krotodc.specgenerators.function
+
+import com.google.protobuf.Descriptors.Descriptor
+import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.FunSpec
+import com.squareup.kotlinpoet.ParameterSpec
+import io.github.mscheong01.krotodc.import.FunSpecsWithImports
+import io.github.mscheong01.krotodc.import.Import
+import io.github.mscheong01.krotodc.specgenerators.FunSpecGenerator
+import io.github.mscheong01.krotodc.util.krotoDCTypeName
+import io.github.mscheong01.krotodc.util.protobufJavaTypeName
+
+class FromJsonFunctionGenerator : FunSpecGenerator<Descriptor> {
+    override fun generate(descriptor: Descriptor): FunSpecsWithImports {
+        val imports = mutableSetOf<Import>()
+        val generatedType = descriptor.krotoDCTypeName
+        val generatedTypeCompanion = ClassName(
+            generatedType.packageName,
+            *generatedType.simpleNames.toTypedArray(),
+            "Companion"
+        )
+        val protoType = descriptor.protobufJavaTypeName
+        val functionBuilder = FunSpec.builder("fromJson")
+            .addParameter(
+                ParameterSpec.builder(
+                    "json",
+                    String::class
+                ).build()
+            )
+            .receiver(generatedTypeCompanion)
+            .returns(generatedType)
+        functionBuilder.addCode("return %L.newBuilder().apply { JsonFormat.parser().ignoringUnknownFields().merge(json, this@apply) }.build().toDataClass();\n", protoType)
+
+        imports.add(Import("com.google.protobuf.util", listOf("JsonFormat")))
+        return FunSpecsWithImports(
+            listOf(functionBuilder.build()),
+            imports
+        )
+    }
+}

generator/src/main/kotlin/io/github/mscheong01/krotodc/specgenerators/function/ToJsonFunctionGenerator.kt

@@ -0,0 +1,37 @@
+// Copyright 2024 Minsoo Cheong
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package io.github.mscheong01.krotodc.specgenerators.function
+
+import com.google.protobuf.Descriptors.Descriptor
+import com.squareup.kotlinpoet.FunSpec
+import io.github.mscheong01.krotodc.import.FunSpecsWithImports
+import io.github.mscheong01.krotodc.import.Import
+import io.github.mscheong01.krotodc.specgenerators.FunSpecGenerator
+import io.github.mscheong01.krotodc.util.krotoDCTypeName
+
+class ToJsonFunctionGenerator : FunSpecGenerator<Descriptor> {
+    override fun generate(descriptor: Descriptor): FunSpecsWithImports {
+        val imports = mutableSetOf<Import>()
+        val generatedType = descriptor.krotoDCTypeName
+        val functionBuilder = FunSpec.builder("toJson")
+            .receiver(generatedType)
+            .returns(String::class)
+        functionBuilder.addCode("return JsonFormat.printer().print([email protected]())")
+        imports.add(Import("com.google.protobuf.util", listOf("JsonFormat")))
+        return FunSpecsWithImports(
+            listOf(functionBuilder.build()),
+            imports
+        )
+    }
+}

generator/src/test/kotlin/io/github/mscheong01/krotodc/JsonConverterTest.kt

@@ -0,0 +1,39 @@
+// Copyright 2024 Minsoo Cheong
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package io.github.mscheong01.krotodc
+
+import io.github.mscheong01.test.Person
+import io.github.mscheong01.test.krotodc.person.fromJson
+import io.github.mscheong01.test.krotodc.person.toDataClass
+import io.github.mscheong01.test.krotodc.person.toJson
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+
+class JsonConverterTest {
+
+    @Test
+    fun `test simple message`() {
+        val proto = Person.newBuilder()
+            .setName("John")
+            .setAge(30)
+            .build()
+        val dataClass = proto.toDataClass()
+        val json = dataClass.toJson()
+        Assertions.assertThat(json).isEqualTo(
+            "{\n  \"name\": \"John\",\n  \"age\": 30\n}"
+        )
+        val deserializedDataClass = io.github.mscheong01.test.krotodc.Person.fromJson(json)
+        Assertions.assertThat(dataClass).isEqualTo(deserializedDataClass)
+    }
+}