From 3b06ec5e08ab183d251245b3156a46332ccfd0a4 Mon Sep 17 00:00:00 2001
From: Pieter van Ginkel <pvginkel@gmail.com>
Date: Sun, 7 Sep 2014 09:12:58 +0200
Subject: [PATCH] Fixed class loader of the script engine.

The script engine didn't have the plugin class loader. Instead, it had the thread context class loader. The problem with this is that this prevents scripts from instantiating classes from other plugins to e.g. implement undo when WorldEdit is available. The thread context class loader is now set to the plugin class loader while instantiating the script engine which solves this issue.
---
 .../scriptcraft/ScriptCraftPlugin.java        | 26 ++++++++++++-------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/main/java/net/walterhiggins/scriptcraft/ScriptCraftPlugin.java b/src/main/java/net/walterhiggins/scriptcraft/ScriptCraftPlugin.java
index 7a0681c..e000849 100644
--- a/src/main/java/net/walterhiggins/scriptcraft/ScriptCraftPlugin.java
+++ b/src/main/java/net/walterhiggins/scriptcraft/ScriptCraftPlugin.java
@@ -1,13 +1,16 @@
 package net.walterhiggins.scriptcraft;
 
-import java.io.InputStreamReader;
-import javax.script.*;
-import java.util.List;
-import java.util.ArrayList;
-
-import org.bukkit.plugin.java.JavaPlugin;
-import org.bukkit.command.*;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
 import org.bukkit.event.Listener;
+import org.bukkit.plugin.java.JavaPlugin;
+
+import javax.script.Invocable;
+import javax.script.ScriptEngine;
+import javax.script.ScriptEngineManager;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
 
 public class ScriptCraftPlugin extends JavaPlugin implements Listener
 {
@@ -19,12 +22,15 @@ public class ScriptCraftPlugin extends JavaPlugin implements Listener
     @Override
         public void onEnable()
     {
+        Thread currentThread = Thread.currentThread();
+        ClassLoader previousClassLoader = currentThread.getContextClassLoader();
+        currentThread.setContextClassLoader(getClassLoader());
         try{
             ScriptEngineManager factory = new ScriptEngineManager();
             this.engine = factory.getEngineByName("JavaScript");
 	    if (this.engine == null){
 		this.getLogger().severe(NO_JAVASCRIPT_MESSAGE);
-	    } else { 
+	    } else {
 		Invocable inv = (Invocable)this.engine;
 		this.engine.eval(new InputStreamReader(this.getResource("boot.js")));
 		inv.invokeFunction("__scboot", this, engine);
@@ -32,6 +38,8 @@ public class ScriptCraftPlugin extends JavaPlugin implements Listener
         }catch(Exception e){
             e.printStackTrace();
             this.getLogger().severe(e.getMessage());
+        }finally{
+            currentThread.setContextClassLoader(previousClassLoader);
         }
     }
     public List<String> onTabComplete(CommandSender sender, Command cmd,
@@ -62,7 +70,7 @@ public class ScriptCraftPlugin extends JavaPlugin implements Listener
 	    this.getLogger().severe(NO_JAVASCRIPT_MESSAGE);
 	    return false;
 	}
-        try { 
+        try {
             jsResult = ((Invocable)this.engine).invokeFunction("__onCommand", sender, cmd, label, args);
         }catch (Exception se){
             this.getLogger().severe(se.toString());