WurmServerModLauncher

Wurm Unlimited Mod Launcher

ModLauncher for WurmUnlimited + a few simple mods

• Mod to remove priest restrictions
• Mod to avoid crop growing to weeds

How to write a simple Mod

• A descriptor modname.properties must exist in folder mods

• The descriptor must contain a line "classname=ClassName" which points to main class of the mod

• The descriptor must contain a line "classpath=libfile.jar" which points to the required libraries in mods/modname (comma separated)

    classname=org.gotti.wurmunlimited.mods.cropmod.CropMod
    classpath=cropmod.jar
    disableWeeds=true
  

• The filesystem should look like this

    mods
    ->	cropmod.properties
    ->	cropmod
    	->	cropmod.jar
  

• Mods must implement org.gotti.wurmunlimited.modloader.interfaces.WurmMod

• If configuration options from the descriptor are supported then Configurable must be implemented too

    public class CropMod implements WurmMod, Configurable {
    	private boolean disableWeeds = true;
    	private Logger logger = Logger.getLogger(this.getClass().getName());
  
    	//
    	// The method configure is called when the mod is being loaded
    	//
    	@Override
    	public void configure(Properties properties) {
    
    		disableWeeds = Boolean.valueOf(properties.getProperty("disableWeeds", Boolean.toString(disableWeeds)));
    		logger.log(Level.INFO, "disableWeeds: " + disableWeeds);
    
    		//
    		// We initialize a method hook that gets called right before CropTilePoller.checkForFarmGrowth is called
    		//
    		if (disableWeeds) {
    			try {
    
    				//
    				// To make sure we hook the correct method the list of method parameter types is compiled
    				//
    				CtClass[] paramTypes = {
    						CtPrimitiveType.intType,
    						CtPrimitiveType.intType,
    						CtPrimitiveType.intType,
    						CtPrimitiveType.byteType,
    						CtPrimitiveType.byteType,
    						HookManager.getInstance().getClassPool().get("com.wurmonline.mesh.MeshIO"),
    						CtPrimitiveType.booleanType
    				};
    				
    				//
    				// next we register the hook for 
    				// com.wurmonline.server.zones.CropTilePoller.checkForFarmGrowth(int, int, int, byte, byte, MeshIO, boolean) 
    				//
    				HookManager.getInstance().registerHook("com.wurmonline.server.zones.CropTilePoller", "checkForFarmGrowth", Descriptor.ofMethod(CtPrimitiveType.voidType, paramTypes), new InvocationHandler() {
    	
    					//
    					// The actual hook is an InvocationHandler. It's invoke method is called instead of the hooked method.
    					// The object, method and arguments are passed as parameters to invoke()
    					//
    					@Override
    					public Object invoke(Object object, Method method, Object[] args) throws Throwable {
    						//
    						// When the hook is called we can do stuff depending on the input parameters
    						// Here we check if the tileAge is 6 (the second ripe stage)
    						//
    						byte aData = ((Number)args[4]).byteValue();
    						final int tileState = aData >> 4;
    						int tileAge = tileState & 0x7;
    						if (tileAge == 6) {
    							// tileAge is 6. Advancing it further would create weeds. 
    							// Therefor we just exit here. 
    							// return null is required if the hooked method has a void return type 
    							return null;
    						}
    	
    						//
    						// tileAge is not 6. We just continue by calling the hooked method
    						//
    						return method.invoke(object, args);
    					}
    				});
    			} catch (NotFoundException e) {
    				throw new HookException(e);
    			}
    		}
    	}
    }