Java, jump back in code possible?

[DreX]

Is there a way I can jump back in code in Java.
Example:
   The programm senses an error, it calls a method. The method preforms a "hard reset (a part of programm that puts back everything they way it was-for the question it isn't important what this does) and then starts the main method from start again (without finishing the main method).

I can't (don't know how) to use break/return because they only exit the inner loop...and I already have an inner loop (the loop that checks for errors..)...so return/break would only escape the error checking loop and would not return me to the start.

[HTH]

Ironically, and IIRC btw, you can use a break. Java doesnt let young programmers use Goto becase gotos are evil and bad programming, but if you need to break out of a larger loop based on something inside of a smaller loop... you can do this:

Code: [Select]

outer:
for (int i = 0; i < I_MAX; i++) {
for (int j = 0; i < J_MAX; j++){
// bla bla bla error checking or something
break outer; //Will break out of the loop designated by outer.
}
}
Now i'm not a java coder at all; hate the fucking stuff. But if i was a java coder and you wanted exactly what you said in your post I'd say use something like this;

Code: [Select]

Boolean isGood = true;
outer:
for (int i = 0; i < I_MAX; i++) {
for (int j = 0; i < J_MAX; j++){
// bla bla bla error checking or something
isGood = false;
break outer; //Will break out of the loop designated by outer.
}
}
if (isGood) {
doSomething();
} else {
doSomethingElse();
}

BUt like I said Im no Java coder and Im sure someone else will chime in

[Deque]

The problem you describe is best handled with exceptions.
Example:

Code: (Java) [Select]

public static void main(String... args) {
    //you told me, you want to jump back here, so we place a check if the call was successfull
    boolean success = false;
    while(!success) {
       try {
           //you call your method, if an exception occurs, you will jump to catch
           doSomething();
           // if no exception occured, this will be executed
           success = true;
       } catch (IllegalStateException e) {
           // you may decide to print the message here
           System.err.println(e.getMessage());
       }
   }
}

public static void doSomething() throws IllegalStateException {
     //you call your method, but you don't care about handling the exceptional case here
    int i = problematicMethod() + 1;
    // is only executed, if no exception occurs
    System.out.println(i);
}

private static int problematicMethod() throws IllegalStateException {
    //something goes wrong
    if(somethingIsWrong()) {
        //the rest of the code in this method will not be executed
        throw new IllegalStateException("error message");
    }
    int i = 1;
    return i;
}

While that might seem more complicated than jumping (which is only partly possible in Java), it is actually less error prone with large projects. You have a declaration for the exceptional exit. Every caller will know that an exception might happen and can decide to handle it now or throw it further.

----------------------------------------------

Ironically, and IIRC btw, you can use a break. Java doesnt let young programmers use Goto becase gotos are evil and bad programming,

Java does not let old fags do that either. 

[proxx]

I love GOTO and global variables!
Who the fuck needs returns anyway.

[Deque]

I love GOTO and global variables!
Who the fuck needs returns anyway.

From now on I only want to see assembly code from you and nothing else.

[HTH]

The problem you describe is best handled with exceptions.
Example:

Code: (Java) [Select]

public static void main(String... args) {
    //you told me, you want to jump back here, so we place a check if the call was successfull
    boolean success = false;
    while(!success) {
       try {
           //you call your method, if an exception occurs, you will jump to catch
           doSomething();
           // if no exception occured, this will be executed
           success = true;
       } catch (IllegalStateException e) {
           // you may decide to print the message here
           System.err.println(e.getMessage());
       }
   }
}

public static void doSomething() throws IllegalStateException {
     //you call your method, but you don't care about handling the exceptional case here
    int i = problematicMethod() + 1;
    // is only executed, if no exception occurs
    System.out.println(i);
}

private static int problematicMethod() throws IllegalStateException {
    //something goes wrong
    if(somethingIsWrong()) {
        //the rest of the code in this method will not be executed
        throw new IllegalStateException("error message");
    }
    int i = 1;
    return i;
}

While that might seem more complicated than jumping (which is only partly possible in Java), it is actually less error prone with large projects. You have a declaration for the exceptional exit. Every caller will know that an exception might happen and can decide to handle it now or throw it further.

----------------------------------------------

Java does not let old fags do that either. 

I knew someone would chime in with the technically correct answer I didn't know (or at least remember) exactly how to deal with exceptions in java. And I meant it more of "They didnt implement it so young programmers who dont know any better couldnt release code filled with GOTOs... because fuck GOTOs. And Global Variables. (Proxx)"

[proxx]

I knew someone would chime in with the technically correct answer I didn't know (or at least remember) exactly how to deal with exceptions in java. And I meant it more of "They didnt implement it so young programmers who dont know any better couldnt release code filled with GOTOs... because fuck GOTOs. And Global Variables. (Proxx)"

Sarcasm.

[HTH]

Acknowledgement of Sarcasm

[DreX]

thank you all, I managed it (some combination of while and exceptions...)

[kenjoe41]

I love GOTO and global variables!
Who the fuck needs returns anyway.

Fkcu ball, come to C++ and sure as hell you will be wiping your nose with a door mat if you try GOTO stuff in a sensible project. I wonder if mozilla cleaned up its code cos it had alot of those.

[proxx]

Fkcu ball, come to C++ and sure as hell you will be wiping your nose with a door mat if you try GOTO stuff in a sensible project. I wonder if mozilla cleaned up its code cos it had alot of those.

You got the part where I was joking too?

[kenjoe41]

Yup, but rolling with the breeze. When did EZ become so stall.

[Architect]

Yup, but rolling with the breeze. When did EZ become so stall.

The real hackers are here still, just fapping to more useful things.