PreUpdate not firing when adding to a collection [duplicate]

Answer 1

Here is my implementation for Hibernate provider:

http://pastebin.com/8cPB96bZ

Generally you just mark methods that should be called in the case of a dirty collection with @PreCollectionChange annotation.

Answer 2

@PreUpdate event is triggered just before database UPDATE operation is executed for the entity in question.

If you're not updating direct properties of Employee, there's no UPDATE to execute for its table and thus @PreUpdate listener is never called. You should have better luck using @PrePersist event which is triggered by "flush" rather than "update".

Answer 3

Maybe a this custom workaround works:

Create a subclass of ArrayList which identifies changes through ActionListener pattern

public class Employee {
    ....

    private List<Employee> minions = createChangeNotifierList();

    private List<Employee> createChangeNotifierList() {
        ChangeNotifierList<Employee> l = new ChangeNotifierList<Employee>();
        l.setActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                preUpdate();
            }
        });
        return l;
    }

    public void setMinions(List<Employee> l) {
        if (!(l instanceof ChangeNotifierList)) {
            l = createChangeNotifierList();
            preUpdate();
        }
        this.minions = l;
    }

    public void preUpdate(){ ... }
}


public class ChangeNotifierList<T> extends ArrayList<T> {

    private ActionListener actionListener;

    public ChangeNotifierList() {
    }

    public ChangeNotifierList(List<T> list) {
        super.addAll(list);
    }

    public void setActionListener(ActionListener actionListener) {
        this.actionListener = actionListener;
    }

    public boolean add(T e) {
        boolean b = super.add(e);
        if (b) {
            notifyChange();
        }
        return b;
}

    private void notifyChange() {
        actionListener.actionPerformed(null);
    }

    .....
}