Question

I am looping through a set of beans and doing a check for something and adding to a list. I only want to add one occurrence of a particular item

List<PartsBean> beans = hotPartsDAO.getDeletedList(user);
List<FinalItemBean> finalItemList = new ArrayList<FinalItemBean>();
for (PartsBean bean : beans)
{
    if (!bean.getFinalItem().isActive())
    {
        finalItemList.add(bean.getFinalItem());
    }
}

In the list I get for example

"test"
"test"
"test"
"hello"

I just want 1 “test”

If I were to use a set then how would I modify this so that I can add the components of that set to this below:

This here is how its currently being passed over List<FinalItemBean> list

protected final void buildFinalItemFilterList( Action action, PartsDAO dao, List<FinalItemBean> list )

    throws SQLException
{
    List<FinalItemBean> finalItems = dao.getAllFinalItems( false );
    FinalItemBean finalItem;

    for (FinalItemBean e: list )
    {
         finalItem = dao.getFinalItemById(e.getId());
         finalItems.add(finalItem);
    }

    Collections.sort( finalItems );
    action.setRequestAttribute("finalItems", finalItems );
}

Answer 1

The interface list has a Method called contains, which return a true if that ‘occurrence’ is on the list and a false if is not in the list.
Like:

if(!myList.contains(person)) myList.add(person);

Pretty easy. You could also use a Set instead, but, I think lists are more flexible than sets, or that’s what some developers believe.