I can get/create the directory of the file but have trouble returning the correct data type.
public fighter rndmFighter(int z) throws Exception
{
File here = new File("encounter.java");
String path = here.getAbsolutePath();
path = path.substring(0,path.lastIndexOf("/"));
path +="/Zones/"+z+"/enemy";
File zone = new File(path);
File[] items = zone.listFiles();
int r = (int)(Math.random()*(items.length));
fighter t = items[r].getName();
return t;
}
creates the directory ./Zones/(an integer like 1)/(random).class but I have no idea how to access the information in said directory (past something like a text document)
example of a passed class file
public class imp extends fighter implements monster {
private String name = "";
public imp(int health, int attack, int amr) {
super("imp", health, attack, amr);
randomName();
setGoldVal(4);
setDodge(15);
exp(3);
}
public imp() {
super("imp", (10 + (int) (Math.random() * 10)), 4 + (int) (Math.random() * 2), 0);
randomName();
setGoldVal((int) (Math.random() * 5));
setDodge(10 + (int) (Math.random() * 10));
exp(expVal());
}
public void Name(String n) {
n = name;
}
public void randomName() {
int x = (int) (Math.random() * 5);
switch (x) {
case 1:
name = "Zoryap";
break;
case 2:
name = "Yazkin";
break;
case 3:
name = "Azbis";
break;
case 4:
name = "Quzlop";
break;
case 5:
name = "Ziltik";
break;
default:
name = "Taylor Rogers";
break;
}
}
public int expVal() {
return 1 + (int) (Math.random() * 4);
}
public String toString() {
if (HP() < 0)
return name + ", the deceased imp.";
return name + super.toString();
}
}
The class files must be created in this way and it must return a random file from the directory, this is a class project where other people have to be able to create their own classes and add them to my code, and I don't want people to have to change my source files.
Yes, all of the files that I am trying to access are compiled.
current version of rndmFighter()
public Object rndmFighter(int z)throws Exception
{
File here = new File("encounter.java");
String path = here.getAbsolutePath();
path = path.substring(0,path.lastIndexOf("/"));
path +="/Zones/"+z+"/enemy";
File zone = new File(path);
File[] items = zone.listFiles();
int r = (int)(Math.random()*(items.length));
path+="/"+items[r].getName();
ClassLoader classLoader = ClassLoader.getSystemClassLoader();
Class myClass = classLoader.loadClass(path);
Object t = myClass.newInstance();
return t;
}
the issue with this is that it returns ClassNotFoundException in the runner (same directory as the encounter class)
Exception in thread "main" java.lang.ClassNotFoundException: /home/user/Documents/Text Adventure/Zones/1/enemy/imp.class
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at encounter.rndmFighter(encounter.java:30)
at testGame.main(testGame.java:12)
using the line
fighter e = fighter.class.cast(t.rndmFighter(1));
to access the method.
It is not clear from the question if you expect already compiled .class files or source code (.java files). For the later I suppose you need javax.tools.JavaCompiler
to compile .java files on the fly. To load third party .class files on the fly you need something like:
ClassLoader classLoader = ClassLoader.getSystemClassLoader();
Class myClass = classLoader.loadClass(classNameToBeLoaded);
Object instance = myClass.newInstance();
Aren't you concerned with security issues? For example, what if a third party code contains System.exit() call and you invoke it at some point?
I have resolved my issue using URLClassLoader
public Object rndmFighter(int z)throws Exception
{
File here = new File("encounter.java");
String path = here.getAbsolutePath();
path = path.substring(0,path.lastIndexOf("/"));
path +="/Zones/"+z+"/enemy";
File zone = new File(path);
File[] items = zone.listFiles();
int r = (int)(Math.random()*(items.length));
String s = items[r].getName().substring(0,items[r].getName().indexOf("."));
URL url = zone.toURL();
URL[] urls = new URL[]{url};
ClassLoader cl = new URLClassLoader(urls);
Class myClass = cl.loadClass(s);
Object t = myClass.newInstance();
return t;
}
This system allows me to pull the required .class files and create the necessary constructor. Thanks for the pointers though :D
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