@Override
    public int hashCode() {
        int hash = 5;

        hash = 97 * hash + ( ( this.id != null )
                ? this.id.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.title != null )
                ? this.title.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.price != null )
                ? this.price.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.description != null )
                ? this.description.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.isbn != null )
                ? this.isbn.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.nbOfPages != null )
                ? this.nbOfPages.hashCode()
                : 0 );
        hash = 97 * hash + ( ( this.illustrations != null )
                ? this.illustrations.hashCode()
                : 0 );

        return hash;
    }