[Resource] ReflectionExecutor - Finally readable reflection!

What can ReflectionExecutor do?

The reflection way of sending a packet:

Code:java

Object handle = p.getClass().getMethod("getHandle").invoke(p);
 
Object connection = handle.getClass().getField("playerConnection").get(handle);
connection.getClass().getMethod("sendPacket", Object.class).invoke(connection, packet);

The ReflectionExecutor way of sending a packet:

Code:java

ReflectionExecutor.execute("getHandle().playerConnection.sendPacket({1})", p, packet);

The reflection way of creating a Packet20NamedEntitySpawn:

Code:java

String NMS_PATH = "net.minecraft.server." + (Bukkit.getServer() != null ? Bukkit.getServer().getClass().getPackage().getName().replace(".", ",").split(",")[3] : "UNKNOWN");
Class<?> packetClass = Class.forName(NMS_PATH+".Packet20NamedEntitySpawn");
Constructor<?> constr = packetClass.getConstructor(Class.forName(NMS_PATH+".EntityHuman"));
Object packet = constr.newInstance(p.getClass().getMethod("getHandle").invoke(p));

The ReflectionExecutor way of creating a Packet20NamedEntitySpawn:

Code:java

ReflectionObject packet = ReflectionObject.fromNMS("Packet20NamedEntitySpawn", ReflectionExecutor.execute("getHandle()", p));

What is ReflectionExecutor?
ReflectionExecutor is an utility class written by me. It aims to simplify the difficult process of bypassing the limits of referencing NMS. ReflectionExecutor exists of two parts:

• The Executor part
• The Object part

Using the executor
Using the executor is not that hard really. It only contains one method. Execute.

Code:

ReflectionExecutor.execute(command, toCallOn, args);

Command => The command to call. getHandle() for example
toCallOn => The object the provided command needs to be called on. the player for example
args => The arguments. These can be referenced with {Argument Number} in your code. The first argument can be referenced by {1}.
For example:

Code:java

String str = "Demo";
System.out.println(ReflectionExecutor.execute("charAt({1})", str, 1); //Prints e

Using the object
ReflectionExecutor also contains a subclass called ReflectionObject. This is used for modifying objects. Here is how you make one:

Code:

new ReflectionObject(object);

object => the object the ReflectionObject wraps around.

Code:

ReflectionObject.fromNMS(nmsClass, arguments);

This method tries to create a new instance of nmsClass with the specified arguments. If it succeeds, it will return the created object wrapped in a ReflectionObject.
nmsClass => The NMS class. Can be a member of net.minecraft.server.VERSION. (For example, Packet20NamedEntitySpawn), or a normal java class (For example, java.lang.String)
For all the methods, see the documentation!
Downloads
Find the download here
Documentation here

Placeholder for future stuff

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

molenzwiebel This looks really nice. I will probably not use it in the future because I just finished my own reflection framework :/ (which contains more features then yourse, anyways this is a neat tool )

 

Neat, I might be looking into using this in the future.

 

molenzwiebel Does this still work?

 

Yep.

 

molenzwiebel Very nice library. I'm having some issues though, especially with calling a third class to execute a function on an object with a second object, case in point:

Code:java

System.out.println(ReflectionExecutor.NMS_PATH + "NMS PATH"); //just a check
 
            ReflectionObject es = ReflectionObject.fromNMS("EntityWitherSkull", ReflectionExecutor.execute("getHandle()", loc.getWorld()));
            ReflectionObject.fromNMS("Entity", ReflectionExecutor.execute("setLocation()", es,loc.getX(), loc.getY() + 1 + 55, loc.getZ(), 0, 0)); //this line. I need to use the Entity class to call setLocation() on my EntityWitherSkull object
            ReflectionExecutor.execute("addEntity()",ReflectionExecutor.execute("getHandle()", loc.getWorld()), es);
            ReflectionObject  hs = ReflectionObject.fromNMS("EntityHorse", ReflectionExecutor.execute("getHandle()", loc.getWorld()));
            ReflectionExecutor.execute("setLocation()",hs, loc.getX(), loc.getY() + 55, loc.getZ(), 0, 0);
            ReflectionExecutor.execute("setAge()", hs, -1700000);
            ReflectionExecutor.execute("setCustomName()", hs, text);
            ReflectionExecutor.execute("setCustomNameVisible()", hs, true);
            ReflectionExecutor.execute("getHandle().playerConnection.sendPacket({1})", p, hs);
 
            ReflectionObject ae = ReflectionObject.fromNMS("PacketPlayOutAttachEntity", 0, hs, es);
            ReflectionExecutor.execute("getHandle().playerConnection.sendPacket({1})", p, ae);
 
            int ides = (int) ReflectionExecutor.execute("getID()",es);
                    int idhs = (int) ReflectionExecutor.execute("getID()",hs);
  return Arrays.asList(ides, idhs );

I believe some of the rest of my code may not work, and if you could spot check that, that would be awesome.
Thanks!

 

reflection may be hard to read only for users who decided "iam very smart and will outsmart bukkit team version barrier".

version barrier placed for a reason, you shoud not try to overcome it, especially in public closed source plugins.

 

I guess the only thing is that some people want their plugin to support more than one version. If they made the plugin automatically break on a new version that they haven't updated it for then I suppose I'd be fine with that, but otherwise the plugin is eventually going to break something.

 

Reason for version barrier "to prevent random destructive issues".

Just imagine situation - you are using NMS World class and some methods like "a" or "b" - in new version method signature left intact, but method completely different.

now it may remove world or regenerate chunks or wipe all animals in world - people who use your plugin, will be happy about "i dont need to update it" very limited amount of time.

after some time i decided to abandon any attempts to overcome version barrier - each version you must double check your NMS code and force users to update.

it will be good move to place some useless import into main class just to force users to update with new major bukkit version.

 

Exactly. It can be useful to make your plugin work with older versions, but you should include something to break it with newer versions until you can verify that it doesn't do anything horrible.

 

If something can be used wrong, it will be used wrong.

Some features must be hard to use or undocumented to prevent random "noobs" from using it.

 

RawCode Although it could be used wrongly around big updates in code (ie 1.6-1.7, 1.7-1.8), the developer could easily use reflection to handle 1.7_R1, R2, R3, which all appear to be non-version specific, but have different names due to Bukkit's nomenclature. Even Bukkit dev only has support for 1.7.2 R1-3 for developers to post their plugins, and most users don't even know how to find out what R version they have, and still think there is no support for, say, 1.7.5 or 9. Using reflection, developers have the option to put out one version of code, which works with every renamed version and revision. When something breaks on a large version update, just change a few things in your code and you're back in business.

 

Read my post, at least single time please, i explained why version barrier exists. ccrama

 

If the last statement was true, then everyone in the world would be standing around, wondering how to use this new fangled thing named "fire".

 

as you may know, currently every state enforce and punish "parents" who let children to start fire.

many objects have notes "keep away from children"