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I'm required to build a program in Java, while I have no idea about it.

I have an integer value stored in an object variable.. And I want to assign the value to another integer variable. but I can't find a way to convert an object to integer...

may you please help with this .. thanks in advance ..

Here is my Code :

public class Bank extends unicastRemoteObject implements BankInterface  
{  

String[] columnNames = {"Account","Balance"};  
Object[][] data = {{"a",10,},{"b",20}};  

public Bank() throws RemoteException { //constructor  
}  

public int getRowCount() { // number of accounts  
  return data.length;  
}  

public Object getValueAt(int row, int col) { // returns the value of the cell   
    return data[row][col];  
}  


public void deposit(int account, int amount) throws RemoteException {     
       // work Description:   
       // find the tuple by searching about the account number  
       // add the amount to balance..  
       // conversions are needed     

     Object accnum;   // to store the account number in. *string*
     Object balancevalue; // to store the balance in. *integer*  
     for ( int i=0 ; i<=getRowCount() ; i++)
             balancevalue = getValueAt(i,2)); // assign the current balance value.. 
             accnum = getValueAt(i,1); // assign the account number..
             int a = 0; // we will assign the integer type of accnum to a.
             int b = 0; // we will assign the integer type of balancevalue to b.
             if( a == account ) { // we find the account number.  
                 b= b + amount ;  // add the amount to the balance.
                 // we need to change the integer "b" into Object to store it in Data[i][2]. 
} 
}
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4
  • This code can impossibly make sense without being changed. The line String a = 0; is incompatible with if( a == account ) since account is declared as int account. Either the method signature must be changed, or the declared type of the variable a must be changed, or the condition for the if statement must be changed to include conversions. Judging by the comments, I feel like the author of the assignment did not intend any of these things to be changed. I would say the person who wrote the assignment was being pretty sloppy, and didn't check his product for correctness. Commented Nov 29, 2011 at 14:44
  • My mistake, Sorry.. I've changed it at the last moment without noticing comparison statement ,because i haven't even checked it syntactically or semantically. About the author, in fact he gave the code without Deposit function. Thanks for alerting. it got corrected. Commented Nov 29, 2011 at 16:11
  • Then don't mind my previous post. I thought that was written by the one who made the assignment, and if there was a mistake in the assignment which was handed to students, that'd be pretty bad. But when you made it yourself it's kind of a good thing. Playing around and seeing what happens when you change thing is good for the learning process. Commented Nov 29, 2011 at 18:39
  • One tip (I am assuming that the instance variables of the class were defined by the author of the assignment): Take note of the data type of the account identifier. Assume that I want to deposit 10 dollars to bank account "b". Will I be able to do that when the deposit(...) method takes two ints as input? Maybe the deposit method should take something else than two ints as input... Commented Nov 29, 2011 at 22:05

5 Answers 5

Reset to default
2

int to Object

int b = 10;
Object o = new Integer(b);

You can wrap your int into an Integer, which is a subclass of Object.

Object to int

Object o = new Integer(10);
int b = (Integer) o;

You can retrieve the value by casting o back to Integer. The JVM will then convert implicitely the Integer back to int.

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Comments

2

Having something like Object[][] data is very bad design. Instead, you should have a class Account with fields accountNumber and balance with the approriate types. Then you have a List<Account>, everything is clean and typesafe, and the getValueAt() method becomes unneccessary.

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4 Comments

You're right, I would love using a class with attributes and derive object from it.. which is ,also, more familiar to me.. but i have this given code and i have no right to modify ,, just complete it. Thanks ..
I think it is too early to start discussing topics like design practices. If you are in the early stages of an "Introduction to programming" course, and you've only covered the topics primitive types, Strings and arrays, you have to start with simplified problems to understand the basics. Obviously, this is an assignment for an "Introduction to programming" course.
No Alderath.. In fact i am advanced in programming with C++. but in Java yes im completely new. Why I have this confusion about Object type, That's because there's no such built-in type in c++.
No Alderath.. In fact i am advanced in programming with C++. but in Java yes im completely new. @ Alderath Also, no this is not an assignment. you can regard it because it sounds so but in fact this is part of a bigger project for network security. and I am obligated to choose Java ,even though i don't know it, because it supports mobile applications and dealing GSM network and such things. Thanks for your help, it's appreciated
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Your data array already stores Object types - account number as String, balance as Integer (an Object wrapper for the primitive int). In your deposit method, you need to parse the account number String to an int value and get the primitive int value of the balance from the Integer.

Here is an example of how to make the conversions in the code you have shown.

 for ( int i=0 ; i<=getRowCount() ; i++)
         Integer balancevalue = (Integer)getValueAt(i,2));
         String accnum = (String)getValueAt(i,1);

         int a = Integer.parseInt(accnum); // parse String to int
         int b = balancevalue.intValue();  // get primitive value of Integer wrapper

         if( a == account ) { // we find the account number.  
             b= b + amount ;  // add the amount to the balance.

             // create new Integer (is an Object)
             Integer newBalance = new Integer(b);

             // store in the data array
             data[row,2] = newBalance;

For the final step - conversion from int to Integer to store in the data array - you could rely on autoboxing instead of explicitly creating the Integer wrapper. So the last two lines of code could be replaced with this:

             // store in the data array
             data[row,2] = b;
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1 Comment

very clear and complete answer.. it's very appreciated. Well, I wrote: data[i][2] = new Integer(b); instead of last two lines. Thanks a lot for your answer.
0

You can use the Integer object which is a wrapper for an int primitive type.

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Comments

0

Just do

Data[i][2] = b;

Auto boxing should work.

If you are using older version of java you can do

Data[i][2] = Integer.valueOf(b);
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1 Comment

This won't help you get the account number (String) as an int.

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