CODEWITHSUNDEEP
javaobjectarraylist
Jiaxuan He
Jiaxuan He

Reputation: 97

How can I permit an ArrayList from removing added objects without overriding or making it immutable

Guys I have created an ArrayList and I don't want to make it immutable. I just seek to find a solution as for how to not allow the ArrayList from removing the objects.

public final class EMailArchive {

    private final String name;
    private final ArrayList <EMail> emailList;
    private final LocalDate date;


    public EMailArchive(String name, ArrayList <EMail> emailList) {
        this.name = name;
        this.emailList = emailList;
        date = LocalDate.now();
    }

    public String getName() {
        return name;
    }

    public LocalDate getDate( ) {
        return date;
    }

    public List <EMail> getEMailList() {
        return emailList;
    }

    public void addEMailToArchive(final EMail mail) {
        emailList.add(mail);
        // the mail added to the list shall not be removed, but how do i do that
    }

}

Upvotes: 1

Views: 158

Answers (2)

Dorian Gray
Dorian Gray

Reputation: 2981

If the solution above with extending ArrayList is not appropriate for whatever reason, you could return a copy within the getter, like this:

public List <EMail> getEMailList() {
    return new ArrayList<>(emailList);
}

Changes to the returned List will not be reflected back to the class member.

Upvotes: 0

vincrichaud
vincrichaud

Reputation: 2208

One way is to implement a subClass of ArrayList that override the remove method

class myArrayLit extends ArrayList {

    public myArrayList() {
        super();
    }

    @Override
    public remove(int index) {}

}

This is a basic example, there are more method to override, to achieve your goal.

Upvotes: 1

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