how to check if an object already exists

[oll3i]

nazwa is a string and yes i used equals(nazwa.eq uals(k.nazwa)) in the equals method

[oll3i]

but now what to do with the buttons problem

[JosAH]

but now what to do with the buttons problem

I don't know; for starters: are both ActionListeners registered with those Buttons
using the same List? Add a lot of System.out.prin tln(...) debug statements and
see what happens.

kind regards,

Jos

ps. does your equals() and hashCode() methods work correctly now?

[oll3i]

thank u a lot lot lot yes they do :)

[oll3i]

i did use lots of System.out.prin t() but the prob is that what's created by one button is not seen by the other button code and where to look 4 solution of that?

[JosAH]

i did use lots of System.out.prin t() but the prob is that what's created by one button is not seen by the other button code and where to look 4 solution of that?

Are both ActionListeners using the same List in which you added your Klient
objects? Print out both lists everytime you access them and see what's in
them. (they both should be two references to one List).

kind regards,

Jos

ps. a List can print itself quite nicely because it overrides the toString() method.

[oll3i]

i walked through the list and i know that the client is in that list but when i do
int index = klienci.indexOf (klient); it returns false

[JosAH]

i walked through the list and i know that the client is in that list but when i do
int index = klienci.indexOf (klient); it returns false

Can't be, the indexOf() method returns an int; -1 possibly if no object was found.
I think you have to recheck your equals() method and your hashCode() method.
Print out what your equals() method has to say about every comparison.

kind regards,

Jos

[oll3i]

that was with contains sorry so it returns -1

but
Klient k1 = new Klient("Jan",20 0);
Klient k2 = new Klient ("Jan",200);

System.out.prin t(k1.equals(k2) );


returns true


int index = klienci.indexOf (klient);

if(index != -1) {
klient = klienci.get(ind ex);
}
else {
// 'klient' is not in the list 'klienci'
}

[JosAH]

that was with contains sorry so it returns -1

but
Klient k1 = new Klient("Jan",20 0);
Klient k2 = new Klient ("Jan",200);

System.out.prin t(k1.equals(k2) );


returns true


int index = klienci.indexOf (klient);

if(index != -1) {
klient = klienci.get(ind ex);
}
else {
// 'klient' is not in the list 'klienci'
}

You did do a 'klienci.add(k1 )' or 'klienci.add(k2 )' did you? If so, can you show
your equals method just to be sure? Add a System.out.prin tln() to your equals()
method to see if it is called by your List.

kind regards,

Jos

[oll3i]

public boolean equals(Object o) {
if (!(o instanceof Klient)) return false;
Klient k = (Klient) o;
return nazwa.equals(k. nazwa) && pieniadze == k.pieniadze;
}

i will show u how it is with the buttons

m_add_client.addActionListener( new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                    	
try{
                    		
 //Klient k = new Klient((String)m_name.getText(),Double.valueOf(m_money.getText().trim()).doubleValue()); 


klienci.add(new Klient((String)m_name.getText(),Double.valueOf(m_money.getText().trim()).doubleValue()));               		
                    	
}catch(NumberFormatException exception){
System.err.println("Nie podana suma pieniedzy");
}  
catch(NullPointerException exception){
System.err.println("?");
}
}
});

then the other button

 m_add.addActionListener( new ActionListener() {
                    public void actionPerformed(ActionEvent e) {
                    	
                    	try{
                    	Cennik c= Cennik.getInstance();
                    	Klient klient = new Klient((String)m_name.getText(),Double.valueOf(m_money.getText().trim()).doubleValue()); 
                    	
                    	
                    
                    	


                    
//if(k.equals(klient)) {klient=k;}  // k is not seen here but that wd solve my problem  i wd only compare the two client objects 

//but i have to find a client in a list 
                       int index = klienci.indexOf(klient);        

                    	if(index != -1) {
                    	  klient = klienci.get(index);
                    	  
                    	} 
                    	else {
                    	  // 'klient' is not in the list 'klienci'
                    	}

                      and the rest of the code

[oll3i]

BTW Happy Easter

[JosAH]

BTW Happy Easter

Happy Easter to you too and to everybody else reading this.

About your equals() method: it seems ok (as well as the rest of your code)
except for one thing: you're comparing two double values; two double values
are almost never equal to each other. Can you add some System.out.prin tln()
methods in your equals() method showing exactly *what* is compared to *what*.
Also print out what the equals() method wants to return. To be sure remove those
doubles from your hashCode() method, i.e. return the hashCode() if those Strings
only.

I think you're almost there. ;-)

kind regards,

Jos

[oll3i]

but first i have the equals method but where in the code is place for that method if i already have a list and i can get the object with klient = klienci.get(ind ex);

also two doubles that may be the reason why int index = klienci.indexOf (klient); returns -1

[JosAH]

but first i have the equals method but where in the code is place for that method if i already have a list and i can get the object with klient = klienci.get(ind ex);

also two doubles that may be the reason why int index = klienci.indexOf (klient); returns -1

Good morning; you could (and should) put these System.out.prin tln() statements
in your own equals() method, i.e. print the values of the two objects to be
compared as well as the boolean that is to be returned to the caller. The List
is the caller of course and you can't change anything in the List code itself.

kind regards,

Jos