Casting java.lang.String to a custom class

Matrix's dialogue system to get dialogues is as follows:

Put a dialogue like this: handledDialogues.put("Bob", (Class<Dialogue>) Bob.class.getCanonicalName());

So I said to myself, why not add them all automatically by file location?

I did this:

Code :

---

		for (File file : new File("bin/com/rs/game/player/dialogues/impl").listFiles()) {
				Class<Dialogue> dialogue = (Class<Dialogue>) Class.forName(file.getName().replaceAll(".class", "").getClass().getCanonicalName());
				if (!handledDialogues.containsKey(dialogue)) {
					handledDialogues.put(file.getName().replaceAll(".class", ""), dialogue);
					System.out.println("put " + file.getName());
				}
			}

---

And now the dialogues in the impl folder are not loading and this error is printed:

Code :

---

java.lang.ClassCastException: java.lang.String cannot be cast to com.rs.game.player.dialogues.Dialogue
	at com.rs.game.player.dialogues.DialogueHandler.getDialogue(DialogueHandler.java:208)
	at com.rs.game.player.DialogueManager.startDialogue(DialogueManager.java:20)
	at com.rs.networking.decoders.handlers.NPCHandler$1.run(NPCHandler.java:96)
	at com.rs.game.player.CoordsEvent.processEvent(CoordsEvent.java:46)
	at com.rs.game.player.Player.processEntity(Player.java:543)
	at com.rs.cores.WorldThread.run(WorldThread.java:34)

---

On line:
return classD.newInstance();

Code :

---

	public static final Dialogue getDialogue(Object key) {
		if (key instanceof Dialogue)
			return (Dialogue) key;
		Class<Dialogue> classD = handledDialogues.get(key);
		if (classD == null)
			return null;
		try {
			return classD.newInstance();
		} catch (Throwable e) {
			Logger.handle(e);
		}
		return null;
	}

---

What does the newInstance() method return?

What variable has a String value?

I don't know what variable has a string value.


Outprinting newInstances gives me:

Code :

---

java.lang.ClassCastException: java.lang.String cannot be cast to com.rs.game.player.dialogues.Dialogue

---

O

Quote:

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Originally Posted by Tyluur

I don't know what variable has a string value.

---

The variable you are casting to com.rs.game.player.dialogues.Dialogue

I want that to be fixed and don't know how.

Can you post the code for the newInstance() method to show what it returns?

Or can you post a small complete program that compiles, executes and shows the problem?

I posted what newInstance returns here: http://www.javaprogrammingforums.com...html#post72103

Can you post the code? Your link does not show the code. It points to an error message.

What Norm meant by "show what it returns" is to get the return value from the signature/footprint of the method. Not to see the error message

That's what is outprinted. I returned it by out.println(classD.newInstance());

Can you post the code for the newInstance() method?

Code :

---

    public T newInstance()
        throws InstantiationException, IllegalAccessException
    {
        if (System.getSecurityManager() != null) {
            checkMemberAccess(Member.PUBLIC, ClassLoader.getCallerClassLoader());
        }
        return newInstance0();
    }

---

It's in the JDK packaging.

Can you post a small complete program that compiles, executes and shows the problem?

The culprit line is here. (PS aren't you from rune-server?)

Code java:

---

Class<Dialogue> dialogue = (Class<Dialogue>) Class.forName(file.getName().replaceAll(".class", "").getClass().getCanonicalName());

---

`file.getName().replaceAll(...)` is a String object, so calling `getClass()` returns String.class. `String.class.getCanonicalName()` will then be "java.lang.String.class", which (after removing the .class extension), when passed through Class.forName(), will return String.class once again... heh. Maybe you should write your code a bit cleaner so you notice simple mistakes like this with ease.

EDIT: To clarify, what you probably want is:

Code java:

---

String name = file.getName();
name = name.substring(0, name.length() - 6);
Class<? extends Dialogue> clazz = Class.forName("com.rs.game.player.dialogues.impl." + name).asSubclass(Dialogue.class);
if (!handledDialogues.containsKey(name)) {
  handledDialogues.put(name, clazz);
}

---

Quote:

---

Originally Posted by veeer

The culprit line is here. (PS aren't you from rune-server?)

Code :

---

Class<Dialogue> dialogue = (Class<Dialogue>) Class.forName(file.getName().replaceAll(".class", "").getClass().getCanonicalName());

---

`file.getName().replaceAll(...)` is a String object, so calling `getClass()` returns String.class. `String.class.getCanonicalName()` will then be "java.lang.String.class", which, when passed through Class.forName(), will return String.class once again... heh. Maybe you should write your code a bit cleaner so you notice simple mistakes like this with ease.

EDIT: To clarify, what you probably want is:

Code :

---

String name = file.getName();
name = name.substring(0, name.length() - 6);
Class<? extends Dialogue> clazz = Class.forName("com.rs.game.player.dialogues.impl." + name).asSubclass(Dialogue.class);
if (!handledDialogues.containsKey(name)) {
  handledDialogues.put(name, clazz);
}

---

---

Yeah, I'm from Rune-Server.