CODEWITHSUNDEEP
java
benjamin
benjamin

Reputation: 261

run a method in an element of an Arraylist in java

I want to know if there's a way to run a method of inside an element of an Arraylist but I don't want to do it with get because it actually changes fields of the element

thanks benny.

Upvotes: 4

Views: 1813

Answers (2)

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 299058

Just to make everything even more clear than all the comments did:

public class ReferenceTester {

    public static void main(final String[] args) {
        final String original = "The One and only one";
        final List<String> list = new ArrayList<String>();
        list.add(original);
        final String copy = list.get(0);
        if (original == copy) {
            System.out.println("Whoops, these are actually two references to the same object.");
        } else {
            System.out.println("References to a different objects? A copy?");
        }
    }

}

Run this class and see what it prints.

Upvotes: 2

aioobe
aioobe

Reputation: 421100

You don't want to do it with get as in yourList.get(5).someMethod()?

The get method will not "extract" the element it returns, it will only return a copy of the reference. Getting + removing is the implementaiton of remove.

So, unless you have overridden the get method it will not modify the list.

Update and clarification:

List<String> list = new ArrayList<String>();
list.add(myObject);         // add a reference to myObject in the list
                            // (remember, you can't pass around objects in java)
list.get(0).someMethod();   // get a copy of that reference and call someMethod()

Upvotes: 4

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