# Reordering instances

It's sometimes useful to allow the user to rearrange instances right from the Entity List. Let's say we want to let the user choose some pages order:

# Generator Command

php artisan sharp:make:reorder-handler <class_name> [--model=<model_name>]

# Write the class

First, we need to write a class for the reordering itself, which must implement Code16\Sharp\EntityList\Commands\ReorderHandler, and therefore the reorder(array $ids) function.

Here's an example with Eloquent and a numerical order column:

class PageReorderHandler implements ReorderHandler
    function reorder(array $ids)
        Page::whereIn("id", $ids)
            ->each(function(Page $page) use ($ids) {
                $page->order = array_search($page->id, $ids) + 1;

# Configure reorder for the front-end

Then, in the SharpEntityList class, we have to configure our reorder handler:

function buildListConfig()
    $this->configureReorderable(new PageReorderHandler());

And that's it! The list now presents a "Reorder" button, and your code will be called when needed.

# Handle exceptions

If you need to abort the process, for any reason, you can raise a Code16\Sharp\Exceptions\SharpException\SharpApplicativeException in the reorder(array $ids) function.