public abstract class AbstractListItemChangeDetector<T> {

    /**
     * Detects changes between two lists of items.
     *
     * @param newItems new items.
     * @param oldItems old items.
     * @return a list of found changes.
     * @throws IllegalArgumentException if any of the provided lists is null.
     */
    public List<ListItemChange> detectChanges(final List<T> newItems, final List<T> oldItems) {
        if (oldItems == null || newItems == null) {
            throw new IllegalArgumentException();
        }

        final var changes = new ArrayList<ListItemChange>();

        final var newCopy = new ArrayList<>(newItems);
        final var oldCopy = new ArrayList<>(oldItems);

        // removes
        changes.addAll(buildRemoves(newCopy, oldCopy));

        // inserts
        changes.addAll(buildInserts(newCopy, oldCopy));

        // moves
        changes.addAll(buildMoves(newCopy, oldCopy));

        // changed items
        changes.addAll(buildChanges(newCopy, oldCopy));

        return changes;
    }

    /**
     * Determines whether the content of an item has changed.
     *
     * @param newItem new item.
     * @param oldItem old item.
     * @return true if the content of the item has changed, false otherwise.
     */
    protected abstract boolean hasContentChanged(final T newItem, final T oldItem);

    /**
     * Determines whether an item is not contained in a list.
     *
     * @param items list of items.
     * @param item item to be checked.
     * @return true if the item is not contained in the list, false otherwise.
     */
    protected abstract boolean notContains(final List<T> items, final T item);

    /**
     * Determines the index of an item in a list.
     *
     * @param items list of items.
     * @param item item to be checked.
     * @return index of the item in the list, or -1 if the item is not contained in the list.
     */
    protected abstract int indexOf(final List<T> items, final T item);

    /**
     * Finds removed items and build a list of detected remove changes.
     *
     * @param newItemsCopy new items copy.
     * @param oldItemsCopy old items copy.
     * @return a list of detected remove changes.
     */
    private List<RemovedListItemChange<T>> buildRemoves(final List<T> newItemsCopy, final List<T> oldItemsCopy) {
        final var removes = new ArrayList<RemovedListItemChange<T>>();

        for (var i = 0; i < oldItemsCopy.size(); i++) {
            final var oldItem = oldItemsCopy.get(i);
            if (notContains(newItemsCopy, oldItem)) {

public ListItemChangeDetector(final ItemComparator<T> itemComparator,
                                  final ItemContentComparator<T> itemContentComparator) {

        if (itemComparator == null || itemContentComparator == null) {
            throw new IllegalArgumentException();
        }

        this.itemComparator = itemComparator;
        this.itemContentComparator = itemContentComparator;
    }

    /**
     * Determines whether the content of an item has changed.
     *
     * @param newItem new item.
     * @param oldItem old item.
     * @return true if the content of the item has changed, false otherwise.
     */
    @Override
    protected boolean hasContentChanged(final T newItem, final T oldItem) {
        return !itemContentComparator.equalContent(newItem, oldItem);
    }

    /**
     * Determines whether an item is not contained in a list.
     *
     * @param items list of items.
     * @param item item to be checked.
     * @return true if the item is not contained in the list, false otherwise.
     */
    @Override
    protected boolean notContains(final List<T> items, final T item) {
        return items.stream().noneMatch(newItem -> itemComparator.equals(newItem, item));
    }

    /**
     * Determines the index of an item in a list.
     *
     * @param items list of items.
     * @param item item to be checked.
     * @return index of the item in the list, or -1 if the item is not contained in the list.
     */
    @Override
    protected int indexOf(final List<T> items, final T item) {
        return IntStream.range(0, items.size()).filter(index -> {
            final var otherItem = items.get(index);
            return itemComparator.equals(item, otherItem);
        }).findFirst().orElse(-1);
    }
}

}
        }

        return moves;
    }

    /**
     * Finds changed items and build a list of detected update changes.
     *
     * @param newItemsCopy new items copy.
     * @param oldItemsCopy old items copy.
     * @return a list of detected update changes.
     */
    private List<UpdatedListItemChange<T>> buildChanges(final List<T> newItemsCopy, final List<T> oldItemsCopy) {
        final var changes = new ArrayList<UpdatedListItemChange<T>>();

        var pos = 0;
        for (final var newItem : newItemsCopy) {
            final var oldPos = indexOf(oldItemsCopy, newItem);
            if (oldPos >= 0) {
                final var oldItem = oldItemsCopy.get(oldPos);

                // compare both items
                if (hasContentChanged(newItem, oldItem)) {
                    // item has changed
                    changes.add(new UpdatedListItemChange<>(oldItem, newItem, pos));
                }
            }
            pos++;
        }

        return changes;
    }
}