EvilZone
Programming and Scripting => Java => Topic started by: DreX on October 16, 2014, 09:49:58 PM
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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.
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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:
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;
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
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The problem you describe is best handled with exceptions.
Example:
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.
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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. :P
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I love GOTO and global variables!
Who the fuck needs returns anyway.
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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.
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The problem you describe is best handled with exceptions.
Example:
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.
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Java does not let old fags do that either. :P
I knew someone would chime in with the technically correct answer :D 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)"
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I knew someone would chime in with the technically correct answer :D 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.
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Acknowledgement of Sarcasm
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thank you all, I managed it (some combination of while and exceptions...)
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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.
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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?
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Yup, but rolling with the breeze. When did EZ become so stall.
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Yup, but rolling with the breeze. When did EZ become so stall.
The real hackers are here still, just fapping to more useful things.