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Thread: How to use final operator.

  1. #1
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    Question How to use final operator.

    I had thought final in Java was like const in C++ sorta, or that was what I had wondered upon learning about const in C++.

    I had heard that you might not want a value to be changed and so passed a final object as a parameter and I tested it by changing the value and it let me.

    What's more, I tried making the whole method final and then calling it and using the returned (anonymous) object to call a set method and it let me do it.

    I thought "final" meant it can't be changed.

     
    /**
     * Write a description of class Example here.
     * 
     * @author (your name) 
     * @version (a version number or a date)
     */
    public class Example
    {
        // instance variables - replace the example below with your own
        private int x;
        private String words;
     
        /**
         * Constructor for objects of class Example
         */
        public Example(int x, String words)
        {
            setX(x);
            setWords(words);
        }
     
        public Example()
        {
     
        }
     
     
        public int getX()
        {
     
            return x;
        }
     
        public void setX(int x)
        {
            this.x = x;
        }
     
        public void setWords(String words)
        {
        this.words = words;
    }
     
     
    public String getWords()
    {
    return words;
    }
     
    // sets the values of this new Example object to the values of the parameter
    public final Example copy(  final Example ex)
    {
    Example ex2 = new Example(ex.getX(), ex.getWords());
    ex.setX(3);
    return (ex2);
    }
     
    public static void main(String[] args)
    {
    Example ex = new Example(5,"bob");
    Example ex2 = new Example(4, "mike");
    ex = ex.copy(ex2);
    ex.copy(ex2).setX(3);
    System.out.println(ex.getX());
    }
     
    }

    I had been trying to get it to see if there was a way in a clone method you could make it so the object you're cloning CAN'T be changed (by mistake) in the method.
    Last edited by javapenguin; September 9th, 2011 at 06:01 PM.


  2. #2
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    Default Re: How to use final operator.

    Final is a keyword (not an 'operator'), which means different things in different contexts. Suggested reading:
    final (Java) - Wikipedia, the free encyclopedia
    Do you have a specific question associated with this post?

  3. The Following User Says Thank You to copeg For This Useful Post:

    javapenguin (September 9th, 2011)

  4. #3
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    Default Re: How to use final operator.

    Żou answered my questions with that link.

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