Use TypeSafe Config library instead of Java properties files for the config file format. The default formats are compatible so this should not be disruptive.

build.gradle

@@ -108,7 +108,10 @@ dependencies {
     compile "io.dropwizard.metrics:metrics-core:3.1.2"
 
     // JimFS: in memory java.nio filesystem. Used for test and simulation utilities.
-    compile 'com.google.jimfs:jimfs:1.1'
+    compile "com.google.jimfs:jimfs:1.1"
+
+    // TypeSafe Config: for simple and human friendly config files.
+    compile "com.typesafe:config:1.3.0"
 
     // Unit testing helpers.
     testCompile 'junit:junit:4.12'

src/main/kotlin/core/node/NodeConfiguration.kt

@@ -8,37 +8,19 @@
 
 package core.node
 
-import java.util.*
-import kotlin.reflect.declaredMemberProperties
+import com.typesafe.config.Config
+import com.typesafe.config.ConfigFactory
+import kotlin.reflect.KProperty
 
 interface NodeConfiguration {
     val myLegalName: String
     val exportJMXto: String
 }
 
-object DefaultConfiguration : NodeConfiguration {
-    override val myLegalName: String = "Vast Global MegaCorp"
-    override val exportJMXto: String = ""   // can be "http" or empty
+// Allow the use of "String by config" syntax. TODO: Make it more flexible.
+operator fun Config.getValue(receiver: NodeConfigurationFromConfig, metadata: KProperty<*>) = getString(metadata.name)
 
-    fun toProperties(): Properties {
-        val settings = DefaultConfiguration::class.declaredMemberProperties.map { it.name to it.get(this@DefaultConfiguration).toString() }
-        val p = Properties().apply {
-            for (setting in settings) {
-                setProperty(setting.first, setting.second)
-            }
-        }
-        return p
-    }
-}
-
-/**
- * A simple wrapper around a plain old Java .properties file. The keys have the same name as in the source code.
- *
- * TODO: Replace Java properties file with a better config file format (maybe yaml).
- * We want to be able to configure via a GUI too, so an ability to round-trip whitespace, comments etc when machine
- * editing the file is a must-have.
- */
-class NodeConfigurationFromProperties(private val properties: Properties) : NodeConfiguration {
-    override val myLegalName: String get() = properties.getProperty("myLegalName")
-    override val exportJMXto: String get() = properties.getProperty("exportJMXto")
+class NodeConfigurationFromConfig(val config: Config = ConfigFactory.load()) : NodeConfiguration {
+    override val myLegalName: String by config
+    override val exportJMXto: String by config
 }

src/main/kotlin/demos/TraderDemo.kt

@@ -10,16 +10,16 @@ package demos
 
 import co.paralleluniverse.fibers.Suspendable
 import com.google.common.net.HostAndPort
+import com.typesafe.config.ConfigFactory
 import contracts.CommercialPaper
 import core.*
 import core.crypto.SecureHash
 import core.crypto.generateKeyPair
 import core.messaging.LegallyIdentifiableNode
 import core.messaging.SingleMessageRecipient
-import core.node.DefaultConfiguration
 import core.node.Node
 import core.node.NodeConfiguration
-import core.node.NodeConfigurationFromProperties
+import core.node.NodeConfigurationFromConfig
 import core.node.services.ArtemisMessagingService
 import core.node.services.NodeAttachmentService
 import core.node.services.NodeWalletService
@@ -37,7 +37,6 @@ import java.nio.file.Path
 import java.nio.file.Paths
 import java.security.PublicKey
 import java.time.Instant
-import java.util.*
 import kotlin.system.exitProcess
 import kotlin.test.assertEquals
 
@@ -291,11 +290,8 @@ private fun loadConfigFile(configFile: Path): NodeConfiguration {
         askAdminToEditConfig(configFile)
     }
 
-    val config = configFile.toFile().reader().use {
-        NodeConfigurationFromProperties(
-            Properties(DefaultConfiguration.toProperties()).apply { load(it) }
-        )
-    }
+    System.setProperty("config.file", configFile.toAbsolutePath().toString())
+    val config = NodeConfigurationFromConfig(ConfigFactory.load())
 
     // Make sure admin did actually edit at least the legal name.
     if (config.myLegalName == defaultLegalName)

src/main/resources/reference.conf

@@ -0,0 +1,2 @@
+myLegalName = "Vast Global MegaCorp, Ltd"
+exportJMXto = "http"