CODEWITHSUNDEEP
java
Robert Tossly
Robert Tossly

Reputation: 623

Where can I add exception handling in a Java class definition?

So, I had to create two files. One is a class definition. The other one uses the class' methods/fields.

(Artifact.java) Artifact Class definition:

    public class Artifact {

    int artNumber;
    String arcName;
    String artType;
    int artYear;
    double artWeight;

    Artifact(int artNumber, String arcName, String artType, int artYear,double artWeight) {
        this.artNumber = artNumber;
        this.arcName = arcName;
        this.artType = artType;
        this.artYear = artYear;
        this.artWeight = artWeight;
    }

    public void changeArtYear(int x) {
        this.artYear = x;
    }

    public void changeArcName(String x) {
        this.arcName = x;
    }

    public int getArtNumber() {
        return artNumber;
    }

    public String getArcName() {
        return arcName;
    }

    public String getArtType() {
        return artType;
    }

    public int getArtYear() {
        return artYear;
    }

    public double getArtWeight() {
        return artWeight;
    }

    public String toString(){
        return("The artifact #"+artNumber+" was discovered by "+arcName+". The artifact is made of "+artType+" and was discovered in "+artYear+". The artifact weighs "+artWeight+" kilograms.");
    }


}

(ArtifactTester.java) Testing methods:

public class ArtifactTester {

    public static void main(String[] args){

    Artifact test = new Artifact(88888888,"ben","clay",1624,46.4);          

    System.out.println(test.toString()); //toString()
    System.out.println(test.getArtWeight()); //getArtWeight()
    System.out.println(test.getArtYear()); //getArtYear()
    System.out.println(test.getArtType()); //getArtType()   
    System.out.println(test.getArcName()); //getArcName()   
    System.out.println(test.getArtNumber()); //getArtNumber()   
    test.changeArcName("zack");
    test.changeArtYear(1400);
        System.out.println(test.getArcName()); //getArcName()   
        System.out.println(test.getArtYear()); //getArtYear()
}
}

Anyways, my teacher to told me to add exception handling, but I am not sure where I would add exception handling.

Question: Is it possible to use exception handling in this situation?

Upvotes: 0

Views: 79

Answers (2)

Ashwin Gupta
Ashwin Gupta

Reputation: 2197

Well to be blunt. Yes. Of course. You can use exception handling wherever and whenever you please (most of the time). Although, in this specific case I don't really see a good reason for it. But, I'll take your word for the need. Now, as for where to handle exceptions, this is up to you. You can add exception handling in one of two places. You can either add exception handling when you call the methods like this:

try { //try executing a block of code which may throw exception
    test.toString()
}

catch(Exception e) { //use Exception for all types of exceptions, or make it specific 
    //do something here if the exception is thrown
}

or you can excpetion handle in the methods themselves like so:

 public void changeArtYear(int x) {
    try{
        this.artYear = x;
    }

    catch(Exception e){ //catch the exception that could be thrown
         //do something
    }
}

This should do the trick in your case if you want to add exception handling here. However, I would strongly urge you to learn exception handling and the different exceptions in Java, it is one of the most improtant fundamentals to programming in this language.

Also, let me point this out again: In this program, there is really no need to use exception handling except for practice. There is nothing here that would throw an exception for any reason. (Except maybe a NullPointerException if you passed a null parameter through one of your method calls)

Good Reference/Tutorial: http://www.tutorialspoint.com/java/java_exceptions.htm

This site is an excellent java reference point in general, but specifically for your question today, this page shows you how to work with exceptions.

Upvotes: 2

Sweeper
Sweeper

Reputation: 273510

Is it possible to use exception handling in this situation?

I don't think so. You should probably go and ask your teacher.

In your code, Artifact is just a POJO (Plain Old Java Object). It would not throw any exceptions. All you do in the class is getters and setters, right? How can that throw any exceptions?

You can throw exceptions though. In your setters, you can check whether the argument is null before setting it to the fields. For example:

public void changeArcName(String x) {
    if (x == null) throw new ArgumentException ("x is null!");
    this.arcName = x;
}

Alternatively, you can just use brute force and use try...catch. like this:

Artifact test = new Artifact(88888888,"ben","clay",1624,46.4);          

    try {
        System.out.println(test.toString()); //toString()
        System.out.println(test.getArtWeight()); //getArtWeight()
        System.out.println(test.getArtYear()); //getArtYear()
        System.out.println(test.getArtType()); //getArtType()   
        System.out.println(test.getArcName()); //getArcName()   
        System.out.println(test.getArtNumber()); //getArtNumber()   
        test.changeArcName("zack");
        test.changeArtYear(1400);
        System.out.println(test.getArcName()); //getArcName()   
        System.out.println(test.getArtYear()); //getArtYear()
    } catch (Exception ex) {
        ex.printStackTrace ();
    }

Warning: The catch block can never be reached!

I don't know whether the above is what your teacher wants. Just try both methods and hand it in and see what he/she says!

Upvotes: 0

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