@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((author == null) ? 0 : author.hashCode());
		result = prime * result
				+ ((coverUrl == null) ? 0 : coverUrl.hashCode());
		result = prime * result
				+ ((description == null) ? 0 : description.hashCode());
		result = prime * result + ((id == null) ? 0 : id.hashCode());
		result = prime * result + ((isbn == null) ? 0 : isbn.hashCode());
		result = prime * result + ((status == null) ? 0 : status.hashCode());
		result = prime * result + ((title == null) ? 0 : title.hashCode());
		result = prime * result
				+ ((totalPage == null) ? 0 : totalPage.hashCode());
		result = prime * result
				+ ((yearPublished == null) ? 0 : yearPublished.hashCode());
		return result;
	}