AbstractSelect.select(null) causes NPE in HashMap

[Jonatan Kronqvist]

As a convenience for developers I suggest allowing use of AbstractSelect.select(null);. This allows developers using the toolkit to skip manually converting all null itemIDs into Select.getNullSelectionItemId().

The current implementation is as follows:

public void select(Object itemId) {
	if (!isSelected(itemId) && items.containsId(itemId)) {
		if (isMultiSelect()) {
			final Set s = new HashSet((Set) getValue());
			s.add(itemId);
			setValue(s);
		} else if (itemId.equals(getNullSelectionItemId())) {
			setValue(null);
		} else {
			setValue(itemId);
		}
	}
}

My proposed fix:

public void select(Object itemId) {
	if (itemId == null)
		itemId = getNullSelectionItemId();
		
	if (!isSelected(itemId) && items.containsId(itemId)) {
		if (isMultiSelect()) {
			final Set s = new HashSet((Set) getValue());
			s.add(itemId);
			setValue(s);
		} else if (itemId.equals(getNullSelectionItemId())) {
			setValue(null);
		} else {
			setValue(itemId);
		}
	}
}

The fix is quite simple and should help developers avoid the trap of trying to select null and getting unexpected behavior.

[Artur Signell]

Fixed NPE and added possibility to use select(null) when there is a NullSelectionItem? [5249]