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    <h3>Editing: BelongsToRelationship.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

namespace Illuminate\Database\Eloquent\Factories;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\MorphTo;

class BelongsToRelationship
{
    /**
     * The related factory instance.
     *
     * @var \Illuminate\Database\Eloquent\Factories\Factory|\Illuminate\Database\Eloquent\Model
     */
    protected $factory;

    /**
     * The relationship name.
     *
     * @var string
     */
    protected $relationship;

    /**
     * The cached, resolved parent instance ID.
     *
     * @var mixed
     */
    protected $resolved;

    /**
     * Create a new &quot;belongs to&quot; relationship definition.
     *
     * @param  \Illuminate\Database\Eloquent\Factories\Factory|\Illuminate\Database\Eloquent\Model  $factory
     * @param  string  $relationship
     * @return void
     */
    public function __construct($factory, $relationship)
    {
        $this-&gt;factory = $factory;
        $this-&gt;relationship = $relationship;
    }

    /**
     * Get the parent model attributes and resolvers for the given child model.
     *
     * @param  \Illuminate\Database\Eloquent\Model  $model
     * @return array
     */
    public function attributesFor(Model $model)
    {
        $relationship = $model-&gt;{$this-&gt;relationship}();

        return $relationship instanceof MorphTo ? [
            $relationship-&gt;getMorphType() =&gt; $this-&gt;factory instanceof Factory ? $this-&gt;factory-&gt;newModel()-&gt;getMorphClass() : $this-&gt;factory-&gt;getMorphClass(),
            $relationship-&gt;getForeignKeyName() =&gt; $this-&gt;resolver($relationship-&gt;getOwnerKeyName()),
        ] : [
            $relationship-&gt;getForeignKeyName() =&gt; $this-&gt;resolver($relationship-&gt;getOwnerKeyName()),
        ];
    }

    /**
     * Get the deferred resolver for this relationship's parent ID.
     *
     * @param  string|null  $key
     * @return \Closure
     */
    protected function resolver($key)
    {
        return function () use ($key) {
            if (! $this-&gt;resolved) {
                $instance = $this-&gt;factory instanceof Factory ? $this-&gt;factory-&gt;create() : $this-&gt;factory;

                return $this-&gt;resolved = $key ? $instance-&gt;{$key} : $instance-&gt;getKey();
            }

            return $this-&gt;resolved;
        };
    }
}
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