Create json parsing using moshi

Author: wenli-cai

gradle/libs.versions.toml

@@ -4,6 +4,7 @@ agpVersion = "8.8.0"
 
 compileSdk = "34"
 minSdk = "24"
+moshiKotlinVersion = "1.15.2"
 targetSdk = "33"
 
 jdk-target = "1.8"
@@ -231,6 +232,7 @@ mockito-kotlin = { module = "org.mockito.kotlin:mockito-kotlin", version.ref = "
 
 mockk = { module = "io.mockk:mockk", version.ref = "mockk" }
 
+moshi-kotlin = { module = "com.squareup.moshi:moshi-kotlin", version.ref = "moshiKotlinVersion" }
 reactivestreams = "org.reactivestreams:reactive-streams:1.0.4"
 
 robolectric = { module = "org.robolectric:robolectric", version.ref = "robolectric" }

workflow-trace-viewer/build.gradle.kts

@@ -23,6 +23,7 @@ kotlin {
         implementation(compose.desktop.currentOs)
         implementation(libs.kotlinx.coroutines.swing)
         implementation(compose.materialIconsExtended)
+        implementation(libs.moshi.kotlin)
       }
     }
   }

workflow-trace-viewer/src/jvmMain/kotlin/com/squareup/workflow1/traceviewer/App.kt

@@ -5,5 +5,12 @@ import androidx.compose.runtime.Composable
 
 @Composable
 fun App() {
-  Text("Hello world!")
+  val jsonString = object {}.javaClass.getResource("/workflow-simple.json")?.readText()
+  val root = jsonString?.let { FetchRoot(it) }
+  println(root)
+  if (root != null) {
+    DrawWorkflowTree(root)
+  } else {
+    Text("Empty data or failed to parse data") // TODO: proper handling of error
+  }
 }

workflow-trace-viewer/src/jvmMain/kotlin/com/squareup/workflow1/traceviewer/WorkflowJsonParser.kt

@@ -0,0 +1,27 @@
+package com.squareup.workflow1.traceviewer
+
+import com.squareup.moshi.JsonDataException
+import com.squareup.moshi.Moshi
+import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import java.io.IOException
+
+/**
+ * Parses a JSON string into [WorkflowNode] with Moshi adapters
+ * All the caught exceptions should be handled by the caller, and appropriate UI feedback should be provided to user
+ *
+ */
+public fun FetchRoot(json: String): WorkflowNode? {
+  return try{
+    val moshi = Moshi.Builder()
+      .add(KotlinJsonAdapterFactory())
+      .build()
+    val workflowAdapter = moshi.adapter(WorkflowNode::class.java)
+    val root = workflowAdapter.fromJson(json)
+    root
+  } catch (e: JsonDataException) {
+    throw JsonDataException("Failed to parse JSON: ${e.message}", e)
+  } catch (e: IOException){
+    throw IOException("Malformed JSON: ${e.message}", e)
+  }
+}
+