package com.how2java.tmall.pojo;

import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@Entity
@Table(name = "category")
@JsonIgnoreProperties({ "handler","hibernateLazyInitializer" })

public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    int id;

    String name;

    @Transient
    List<Product> products;
    @Transient
    List<List<Product>> productsByRow;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public List<Product> getProducts() {
        return products;
    }
    public void setProducts(List<Product> products) {
        this.products = products;
    }
    public List<List<Product>> getProductsByRow() {
        return productsByRow;
    }
    public void setProductsByRow(List<List<Product>> productsByRow) {
        this.productsByRow = productsByRow;
    }
    @Override
    public String toString() {
        return "Category [id=" + id + ", name=" + name + "]";
    }
}

package com.how2java.tmall.service;

import java.util.List;

import com.how2java.tmall.pojo.Product;
import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import com.how2java.tmall.dao.CategoryDAO;
import com.how2java.tmall.pojo.Category;

@Service
public class CategoryService {
	@Autowired CategoryDAO categoryDAO;

	public Page4Navigator<Category> list(int start, int size, int navigatePages) {
		Sort sort = new Sort(Sort.Direction.DESC, "id");
		Pageable pageable = new PageRequest(start, size,sort);
		Page pageFromJPA =categoryDAO.findAll(pageable);

		return new Page4Navigator<>(pageFromJPA,navigatePages);
	}
	public List<Category> list() {
    	Sort sort = new Sort(Sort.Direction.DESC, "id");
		return categoryDAO.findAll(sort);
	}

	public void add(Category bean) {
		categoryDAO.save(bean);
	}

	public void delete(int id) {
		categoryDAO.delete(id);
	}

	public Category get(int id) {
		Category c= categoryDAO.findOne(id);
		return c;
	}
	public void update(Category bean) {
		categoryDAO.save(bean);
	}

	public void removeCategoryFromProduct(List<Category> cs) {
		for (Category category : cs) {
			removeCategoryFromProduct(category);
		}
	}

	public void removeCategoryFromProduct(Category category) {
		List<Product> products =category.getProducts();
		if(null!=products) {
			for (Product product : products) {
				product.setCategory(null);
			}
		}

		List<List<Product>> productsByRow =category.getProductsByRow();
		if(null!=productsByRow) {
			for (List<Product> ps : productsByRow) {
				for (Product p: ps) {
					p.setCategory(null);
				}
			}
		}
	}
}

package com.how2java.tmall.dao;

import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.pojo.Product;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;

import java.util.List;

public interface ProductDAO extends JpaRepository<Product,Integer>{
	Page<Product> findByCategory(Category category, Pageable pageable);
	List<Product> findByCategoryOrderById(Category category);
}

package com.how2java.tmall.service;

import com.how2java.tmall.dao.ProductDAO;
import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.pojo.Product;
import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ProductService  {
	
	@Autowired ProductDAO productDAO;
	@Autowired CategoryService categoryService;
	@Autowired ProductImageService productImageService;

	public void add(Product bean) {
		productDAO.save(bean);
	}

	public void delete(int id) {
		productDAO.delete(id);
	}

	public Product get(int id) {
		return productDAO.findOne(id);
	}

	public void update(Product bean) {
		productDAO.save(bean);
	}

	public Page4Navigator<Product> list(int cid, int start, int size,int navigatePages) {
    	Category category = categoryService.get(cid);
    	Sort sort = new Sort(Sort.Direction.DESC, "id");
    	Pageable pageable = new PageRequest(start, size, sort);    	
    	Page<Product> pageFromJPA =productDAO.findByCategory(category,pageable);
    	return new Page4Navigator<>(pageFromJPA,navigatePages);
	}

	public void fill(List<Category> categorys) {
		for (Category category : categorys) {
			fill(category);
		}
	}
	public void fill(Category category) {
		List<Product> products = listByCategory(category);
		productImageService.setFirstProdutImages(products);
		category.setProducts(products);
	}

	public void fillByRow(List<Category> categorys) {
		int productNumberEachRow = 8;
		for (Category category : categorys) {
			List<Product> products =  category.getProducts();
			List<List<Product>> productsByRow =  new ArrayList<>();
			for (int i = 0; i < products.size(); i+=productNumberEachRow) {
				int size = i+productNumberEachRow;
				size= size>products.size()?products.size():size;
				List<Product> productsOfEachRow =products.subList(i, size);
				productsByRow.add(productsOfEachRow);
			}
			category.setProductsByRow(productsByRow);
		}
	}

	public List<Product> listByCategory(Category category){
		return productDAO.findByCategoryOrderById(category);
	}
	
}

package com.how2java.tmall.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class ForePageController {
	@GetMapping(value="/")
	public String index(){
		return "redirect:home";
	} 
	@GetMapping(value="/home")
    public String home(){
        return "fore/home";
    }
}

package com.how2java.tmall.web;

import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.service.CategoryService;
import com.how2java.tmall.service.ProductService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class ForeRESTController {
    @Autowired
    CategoryService categoryService;
    @Autowired
    ProductService productService;

    @GetMapping("/forehome")
    public Object home() {
        List<Category> cs= categoryService.list();
        productService.fill(cs);
        productService.fillByRow(cs);
        categoryService.removeCategoryFromProduct(cs);
        return cs;
    }    

}