Overloading constructors in Java?

Oblivious · Oct 15, 2003, 03:45 PM

I was under the impression that it was possible to overload constructors in Java. Or maybe there is something wrong with my syntax? Can you help me out here guys and gals - whats wrong with this code?

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

Code:

public class Ip_WOccur {
    public char[] ip;
    public int instances;
    /** Creates a new instance of Ip_WOccur */
    public Ip_WOccur( char[] init_ip, int init_instances ){
        instances = init_instances;
        ip = new char[init_ip.length];
        for( int some_var=0 ; some_var<ip.length ; some_var++ ){
            ip[some_var] = init_ip[some_var];
        }
    }
    public Ip_WOccur( char[] init_ip ) {
        this.Ip_WOccur(init_ip, 0);
    }
}

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

Code:

[25:1] cannot resolve symbol
symbol  : method Ip_WOccur (char[],int)
location: class Apache.Apache_Companion.Ip_WOccur
        this.Ip_WOccur(init_ip, 0);
        ^
1 error

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

As you can probably tell, Java is new to me so I would greatly appreciate the efforts of anyone who can share their wisdom with me.

P.S. - I am using Sun Java 1.4.2 VM

baz8080 · Feb 21, 2004, 10:08 PM

this thread is old , and you've probably since fixed it yourself, but dump the 'this.' in front of the 'Ip_WOccur(init_ip, 0);'

'this' is used to reference instance variables. Your instance variables should really also be private, no public.

UberLord · Feb 23, 2004, 12:13 PM

Kinda odd.

this should reference the entire object, including it's private stuff. At least, thats the behaviour under C# and a few other langs - although I really don't know Java

germanjulian · Feb 23, 2004, 12:27 PM

java is very different to C++ and C but has the obvious things which are the same for nearly all programming languages. why are you doing java? cause simply put java is rubbish. avoide like the plague if you can use C or php

UberLord · Feb 23, 2004, 01:49 PM

Quote:

Originally posted by germanjulian
cause simply put java is rubbish

How many languages do you know of that work on PC's, big iron mainframes, pda's and mobile phones?

I only know of one - java. So no, it's not rubbish

baz8080 · Feb 23, 2004, 04:07 PM

I'd be with Uberlord on this one. Java can't be put down as rubbish. It's a 3.5Gl, C is 3, they both have their place. C turns to machinecode, Java to bytecode etc.

The guy is calling a constructor from a constructor, whereas he should have 2 proper constructers. 'this.' is also being used incorrectly here.

It also looks like some of the processing is happening in the first constructor, which is also not advisable. The instance variables are public also, so proper OOP is out the window.

I'm sure he's just learning and has since solved all of this.

Eman Resu · May 31, 2004, 09:48 AM

public Ip_WOccur( char[] init_ip ) {
this(init_ip, 0); <- this is the way it should be done
}

Oct 15, 2003, 03:45 PM	#1
Oblivious DivrerHaeven Seinor Mebmer Join Date: Mar 2003 Location: Baltimore, MD Posts: 236 Rep Power: 0	Overloading constructors in Java? I was under the impression that it was possible to overload constructors in Java. Or maybe there is something wrong with my syntax? Can you help me out here guys and gals - whats wrong with this code? ------------------------------------------------- Code: public class Ip_WOccur { public char[] ip; public int instances; /** Creates a new instance of Ip_WOccur */ public Ip_WOccur( char[] init_ip, int init_instances ){ instances = init_instances; ip = new char[init_ip.length]; for( int some_var=0 ; some_var<ip.length ; some_var++ ){ ip[some_var] = init_ip[some_var]; } } public Ip_WOccur( char[] init_ip ) { this.Ip_WOccur(init_ip, 0); } } ------------------------------------------------------ Code: [25:1] cannot resolve symbol symbol : method Ip_WOccur (char[],int) location: class Apache.Apache_Companion.Ip_WOccur this.Ip_WOccur(init_ip, 0); ^ 1 error ------------------------------------------------------- As you can probably tell, Java is new to me so I would greatly appreciate the efforts of anyone who can share their wisdom with me. P.S. - I am using Sun Java 1.4.2 VM __________________ Pepole olny raed wrods. Btu oyu shuodl sitll check oyur spleling! http://realgar.hopto.org

Feb 23, 2004, 12:13 PM	#3
UberLord A Legend in Underwear Join Date: May 2002 Location: Unknown Posts: 5,255 Rep Power: 0	Kinda odd. this should reference the entire object, including it's private stuff. At least, thats the behaviour under C# and a few other langs - although I really don't know Java __________________ Gentoo Linux - Developer (baselayout) Read my blog "I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours." Stephen Roberts

Feb 23, 2004, 12:27 PM	#4
germanjulian Back in London Join Date: Jul 2003 Location: London Posts: 1,797 Rep Power: 0	java is very different to C++ and C but has the obvious things which are the same for nearly all programming languages. why are you doing java? cause simply put java is rubbish. avoide like the plague if you can use C or php __________________ /\|\ Asus P5W DH Deluxe, Intel C2D E6600, 2GB Corsair XMS2-6400C4 DDR2, E-VGA GeForce 7800 GT, Creative X-Fi Extreme Music, 500GB Seagate 7200.10 SATA, Lian Li PC-V1100 Aluminum Case Black, etc. http://germanjulian.com /\|\

Feb 21, 2004, 10:08 PM	#2
baz8080 DriverHeaven Newbie Join Date: May 2002 Location: Ireland Posts: 16 Rep Power: 0	this thread is old , and you've probably since fixed it yourself, but dump the 'this.' in front of the 'Ip_WOccur(init_ip, 0);' 'this' is used to reference instance variables. Your instance variables should really also be private, no public.

Feb 23, 2004, 04:07 PM	#6
baz8080 DriverHeaven Newbie Join Date: May 2002 Location: Ireland Posts: 16 Rep Power: 0	I'd be with Uberlord on this one. Java can't be put down as rubbish. It's a 3.5Gl, C is 3, they both have their place. C turns to machinecode, Java to bytecode etc. The guy is calling a constructor from a constructor, whereas he should have 2 proper constructers. 'this.' is also being used incorrectly here. It also looks like some of the processing is happening in the first constructor, which is also not advisable. The instance variables are public also, so proper OOP is out the window. I'm sure he's just learning and has since solved all of this.

May 31, 2004, 09:48 AM	#7
Eman Resu Blues man Join Date: Jul 2003 Location: In front of my computer Posts: 35 Rep Power: 0	public Ip_WOccur( char[] init_ip ) { this(init_ip, 0); <- this is the way it should be done }