Refactor commands.

src/main/kotlin/com/beust/kobalt/internal/remote/GetDependenciesCommand.kt

@@ -55,21 +55,18 @@ class GetDependenciesCommand @Inject constructor(val executors: KobaltExecutors,
             projects.add(ProjectData(project.name!!, allDependencies))
         }
         log(1, "Returning BuildScriptInfo")
-        val result = Gson().toJson(GetDependenciesData(projects).toData())
+        val result = toCommandDataJson(Gson().toJson(GetDependenciesData(projects)))
         log(2, "  $result")
         return result
     }
-}
+
+    /////
+    // The JSON payloads that this command uses
+    //
 
     class DependencyData(val id: String, val scope: String, val path: String)
 
     class ProjectData( val name: String, val dependencies: List<DependencyData>)
 
-class GetDependenciesData(val projects: List<ProjectData>) {
-    fun toData() : CommandData {
-        val data = Gson().toJson(this)
-        return CommandData("getDependencies", data)
+    class GetDependenciesData(val projects: List<ProjectData>)
 }
-}
-
-

src/main/kotlin/com/beust/kobalt/internal/remote/KobaltClient.kt

@@ -47,7 +47,7 @@ public class KobaltClient @Inject constructor() : Runnable {
                         done = true
                     } else {
                         val data = jo.get("data").asString
-                        val dd = Gson().fromJson(data, GetDependenciesData::class.java)
+                        val dd = Gson().fromJson(data, GetDependenciesCommand.GetDependenciesData::class.java)
                         println("Read GetDependencyData, project count: ${dd.projects.size()}")
                         line = ins.readLine()
                     }
@@ -59,8 +59,4 @@ public class KobaltClient @Inject constructor() : Runnable {
             }
         }
     }
-
-    fun sendInfo(info: BuildFileCompiler.BuildScriptInfo) {
-        outgoing!!.println("Sending info with project count: " + info.projects.size())
-    }
 }

src/main/kotlin/com/beust/kobalt/internal/remote/KobaltServer.kt

@@ -3,6 +3,7 @@ package com.beust.kobalt.internal.remote
 import com.beust.kobalt.Args
 import com.beust.kobalt.api.Kobalt
 import com.beust.kobalt.misc.log
+import com.google.gson.Gson
 import com.google.gson.JsonObject
 import com.google.gson.JsonParser
 import com.google.inject.Inject
@@ -13,15 +14,43 @@ import java.io.PrintWriter
 import java.net.ServerSocket
 import java.net.SocketException
 
-interface ICommandSender {
-    fun sendData(content: String)
-}
-
+/**
+ * All commands implement this interface.
+ */
 interface ICommand {
+    /**
+     * The name of this command.
+     */
     val name: String
+
+    /**
+     * Run this command based on the information received from the server. When done, use
+     * the sender object to send back a response.
+     */
     fun run(sender: ICommandSender, received: JsonObject)
+
+    fun toCommandDataJson(data: String) = Gson().toJson(CommandData(name, data))
 }
 
+/**
+ * Passed to a command in its `run` method so it can send information back to the caller.
+ * @param The string content that will be sent in the "data" field.
+ */
+interface ICommandSender {
+    fun sendData(data: String)
+}
+
+/**
+ * The JSON payload that commands exchange follow the following pattern:
+ * {
+ *   name: "nameOfTheCommand"
+ *   data: a JSON string containing the payload itself
+ * }
+ * This allows commands to be tested for their name first, after which each command can
+ * decode its own specific payload by parsing the JSON in the "data" field and mapping
+ * it into a Kotlin *Data class. The downside of this approach is a double parsing,
+ * but since the data part is parsed as a string first, this is probably not a huge deal.
+ */
 class CommandData(val commandName: String, val data: String)
 
 @Singleton

src/main/kotlin/com/beust/kobalt/internal/remote/PingCommand.kt

@@ -1,5 +1,7 @@
 package com.beust.kobalt.internal.remote
 
+import com.beust.kobalt.misc.log
+import com.google.gson.Gson
 import com.google.gson.JsonObject
 
 /**
@@ -12,7 +14,14 @@ import com.google.gson.JsonObject
  */
 class PingCommand() : ICommand {
     override val name = "ping"
-    override fun run(sender: ICommandSender, received: JsonObject) =
-            sender.sendData("{ \"response\" : \"${received.toString()}\"" + " }")
+
+    override fun run(sender: ICommandSender, received: JsonObject) {
+        val commandData = toCommandDataJson(Gson().toJson(PingData(received.toString())))
+        val result = Gson().toJson(commandData)
+        log(1, "ping returning: $result")
+        sender.sendData(result)
+    }
+
+    class PingData(val received: String)
 }