package org.dao.impl;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;

import org.dao.DaoException;
import org.dao.ProductDao;
import org.pojo.Product;
import org.utils.DBUtil;

/**
 * 产品Dao实现
 */
public class ProductDaoImpl implements ProductDao {
	/**
	 * 获取所有产品
	 */
	@Override
	public List<Product> getProducts() throws DaoException {
		ResultSet rs = null;
		try {
			List<Product> products = new LinkedList<Product>();
			rs = DBUtil.getResultSet("SELECT id, name, price, count FROM product");
			while(rs.next()) {
				products.add(Product.fromResultSet(rs));
			}
			return products;
		} catch (Exception e) {
			return null;
		} finally {
			DBUtil.clearResultSet(rs);
			DBUtil.closeConnection();
		}
	}

	/**
	 * 保存产品
	 * @param p 产品对象
	 * @return true 保存成功  false 保存失败
	 */
	@Override
	public boolean save(Product p) throws DaoException {
		PreparedStatement st = null;
		try {
			st = DBUtil.getPrepareStatement(
					"INSERT INTO product("
					+ "id, "
					+ "name, "
					+ "price, "
					+ "count) " 
					+ "VALUES("
					+ "null, "
					+ "?, "
					+ "?, "
					+ "?)");
			st.setString(1, p.getName());
			st.setFloat(2, p.getPrice());
			st.setInt(3, p.getCount());
			st.executeUpdate();
			return true;
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			DBUtil.clearPreparedStatement(st);
			DBUtil.closeConnection();
		}
		return false;
	}

	/**
	 * 更新产品
	 * @param p 产品对象
	 * @return true 更新成功 false 更新失败
	 */
	@Override
	public boolean update(Product p) throws DaoException {
		PreparedStatement st = null;
		try {
			st = DBUtil.getPrepareStatement(
					"UPDATE product SET "
					+ "name = ?, "
					+ "price = ?, "
					+ "count = ? " 
					+ "WHERE id = ? ");
			st.setString(1, p.getName());
			st.setFloat(2, p.getPrice());
			st.setInt(3, p.getCount());
			st.setInt(4, p.getId());
			st.executeUpdate();
			return true;
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			DBUtil.clearPreparedStatement(st);
			DBUtil.closeConnection();
		}
		return false;
	}

	/**
	 * 删除产品
	 * @param id 产品编号
	 * @return true 删除成功 false 删除失败
	 */
	@Override
	public boolean delete(int id) throws DaoException {
		PreparedStatement st = null;
		try {
			st = DBUtil.getPrepareStatement("DELETE FROM product WHERE id = ?");
			st.setInt(1, id);
			st.executeUpdate();
			return true;
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			DBUtil.clearPreparedStatement(st);
			DBUtil.closeConnection();
		}
		return false;
	}

	/**
	 * 获取产品对象
	 * @param id 产品编号
	 */
	@Override
	public Product getProdcutById(int id) throws DaoException {
		Product product = null;
		PreparedStatement st = null;
		ResultSet rs = null;
		try {
			st = DBUtil.getPrepareStatement(
					"SELECT id, name, price, count FROM product WHERE id = ?");
			st.setInt(1, id);
			rs = st.executeQuery();
			if(rs.next()){
				product = Product.fromResultSet(rs);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			DBUtil.clearPreparedStatement(st);
			DBUtil.clearResultSet(rs);
			DBUtil.closeConnection();
		}
		return product;
	}

}