DragDrop Custom

@Named
@ViewScoped
public class ColumnManagerView implements Serializable {

    private static final List<String> VALID_COLUMN_KEYS = Arrays.asList("id", "code", "name", "description",
            "price", "category", "quantity");

    private List<ColumnModel> columns = new ArrayList<>();

    private List<Product> products;

    private TreeNode<Product> availableColumns;

    @Inject
    private ProductService service;

    @PostConstruct
    public void init() {
        products = service.getProducts(9);
        createAvailableColumns();
        createDynamicColumns();
    }

    private void createAvailableColumns() {
        availableColumns = new DefaultTreeNode("Root", null);
        TreeNode root = new DefaultTreeNode("Columns", availableColumns);
        root.setExpanded(true);
        TreeNode id = new DefaultTreeNode("column", new ColumnModel("Id", "id"), root);
        TreeNode code = new DefaultTreeNode("column", new ColumnModel("Code", "code"), root);
        TreeNode name = new DefaultTreeNode("column", new ColumnModel("Name", "name"), root);
        TreeNode description = new DefaultTreeNode("column", new ColumnModel("Description", "description"), root);
        TreeNode price = new DefaultTreeNode("column", new ColumnModel("Price", "price"), root);
        TreeNode category = new DefaultTreeNode("column", new ColumnModel("Category", "category"), root);
        TreeNode quantity = new DefaultTreeNode("column", new ColumnModel("Quantity", "quantity"), root);
    }

    public void createDynamicColumns() {
        String[] columnKeys = new String[]{"code", "name", "quantity"};
        columns.clear();

        for (String columnKey : columnKeys) {
            String key = columnKey.trim();

            if (VALID_COLUMN_KEYS.contains(key)) {
                columns.add(new ColumnModel(columnKey.toUpperCase(), columnKey));
            }
        }
    }

    public void treeToTable() {
        Map<String, String> params = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap();
        String property = params.get("property");
        String droppedColumnId = params.get("droppedColumnId");
        String dropPos = params.get("dropPos");

        String[] droppedColumnTokens = droppedColumnId.split(":");
        int draggedColumnIndex = Integer.parseInt(droppedColumnTokens[droppedColumnTokens.length - 1]);
        int dropColumnIndex = draggedColumnIndex + Integer.parseInt(dropPos);

        //add to columns
        this.columns.add(dropColumnIndex, new ColumnModel(property.toUpperCase(), property));

        //remove from nodes
        TreeNode<?> root = availableColumns.getChildren().get(0);
        for (TreeNode node : root.getChildren()) {
            ColumnModel model = (ColumnModel) node.getData();
            if (model.getProperty().equals(property)) {
                root.getChildren().remove(node);
                break;
            }
        }
    }

    public void tableToTree() {
        Map<String, String> params = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap();
        int colIndex = Integer.parseInt(params.get("colIndex"));

        //remove from table
        ColumnModel model = this.columns.remove(colIndex);

        //add to nodes
        TreeNode property = new DefaultTreeNode("column", model, availableColumns.getChildren().get(0));
    }

    public List<Product> getProducts() {
        return products;
    }

    public List<ColumnModel> getColumns() {
        return columns;
    }

    public TreeNode getAvailableColumns() {
        return availableColumns;
    }

    public void setService(ProductService service) {
        this.service = service;
    }

    public static class ColumnModel implements Serializable {

        private String header;
        private String property;

        public ColumnModel(String header, String property) {
            this.header = header;
            this.property = property;
        }

        public String getHeader() {
            return header;
        }

        public String getProperty() {
            return property;
        }
    }
}

@Named
@ApplicationScoped
public class ProductService {

    private List<Product> products;

    @PostConstruct
    public void init() {
        products = new ArrayList<>();
        products.add(new Product(1000, "f230fh0g3", "Bamboo Watch", "Product Description", "bamboo-watch.jpg", 65,
                "Accessories", 24, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1001, "nvklal433", "Black Watch", "Product Description", "black-watch.jpg", 72,
                "Accessories", 61, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1002, "zz21cz3c1", "Blue Band", "Product Description", "blue-band.jpg", 79,
                "Fitness", 2, InventoryStatus.LOWSTOCK, 3));
        products.add(new Product(1003, "244wgerg2", "Blue T-Shirt", "Product Description", "blue-t-shirt.jpg", 29,
                "Clothing", 25, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1004, "h456wer53", "Bracelet", "Product Description", "bracelet.jpg", 15,
                "Accessories", 73, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1005, "av2231fwg", "Brown Purse", "Product Description", "brown-purse.jpg", 120,
                "Accessories", 0, InventoryStatus.OUTOFSTOCK, 4));
        products.add(new Product(1006, "bib36pfvm", "Chakra Bracelet", "Product Description", "chakra-bracelet.jpg", 32,
                "Accessories", 5, InventoryStatus.LOWSTOCK, 3));
        products.add(new Product(1007, "mbvjkgip5", "Galaxy Earrings", "Product Description", "galaxy-earrings.jpg", 34,
                "Accessories", 23, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1008, "vbb124btr", "Game Controller", "Product Description", "game-controller.jpg", 99,
                "Electronics", 2, InventoryStatus.LOWSTOCK, 4));
        products.add(new Product(1009, "cm230f032", "Gaming Set", "Product Description", "gaming-set.jpg", 299,
                "Electronics", 63, InventoryStatus.INSTOCK, 3));
        products.add(new Product(1010, "plb34234v", "Gold Phone Case", "Product Description", "gold-phone-case.jpg", 24,
                "Accessories", 0, InventoryStatus.OUTOFSTOCK, 4));
        products.add(new Product(1011, "4920nnc2d", "Green Earbuds", "Product Description", "green-earbuds.jpg", 89,
                "Electronics", 23, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1012, "250vm23cc", "Green T-Shirt", "Product Description", "green-t-shirt.jpg", 49,
                "Clothing", 74, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1013, "fldsmn31b", "Grey T-Shirt", "Product Description", "grey-t-shirt.jpg", 48,
                "Clothing", 0, InventoryStatus.OUTOFSTOCK, 3));
        products.add(new Product(1014, "waas1x2as", "Headphones", "Product Description", "headphones.jpg", 175,
                "Electronics", 8, InventoryStatus.LOWSTOCK, 5));
        products.add(new Product(1015, "vb34btbg5", "Light Green T-Shirt", "Product Description", "light-green-t-shirt.jpg", 49,
                "Clothing", 34, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1016, "k8l6j58jl", "Lime Band", "Product Description", "lime-band.jpg", 79,
                "Fitness", 12, InventoryStatus.INSTOCK, 3));
        products.add(new Product(1017, "v435nn85n", "Mini Speakers", "Product Description", "mini-speakers.jpg", 85,
                "Clothing", 42, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1018, "09zx9c0zc", "Painted Phone Case", "Product Description", "painted-phone-case.jpg", 56,
                "Accessories", 41, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1019, "mnb5mb2m5", "Pink Band", "Product Description", "pink-band.jpg", 79,
                "Fitness", 63, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1020, "r23fwf2w3", "Pink Purse", "Product Description", "pink-purse.jpg", 110,
                "Accessories", 0, InventoryStatus.OUTOFSTOCK, 4));
        products.add(new Product(1021, "pxpzczo23", "Purple Band", "Product Description", "purple-band.jpg", 79,
                "Fitness", 6, InventoryStatus.LOWSTOCK, 3));
        products.add(new Product(1022, "2c42cb5cb", "Purple Gemstone Necklace", "Product Description", "purple-gemstone-necklace.jpg", 45,
                "Accessories", 62, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1023, "5k43kkk23", "Purple T-Shirt", "Product Description", "purple-t-shirt.jpg", 49,
                "Clothing", 2, InventoryStatus.LOWSTOCK, 5));
        products.add(new Product(1024, "lm2tny2k4", "Shoes", "Product Description", "shoes.jpg", 64,
                "Clothing", 0, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1025, "nbm5mv45n", "Sneakers", "Product Description", "sneakers.jpg", 78,
                "Clothing", 52, InventoryStatus.INSTOCK, 4));
        products.add(new Product(1026, "zx23zc42c", "Teal T-Shirt", "Product Description", "teal-t-shirt.jpg", 49,
                "Clothing", 3, InventoryStatus.LOWSTOCK, 3));
        products.add(new Product(1027, "acvx872gc", "Yellow Earbuds", "Product Description", "yellow-earbuds.jpg", 89,
                "Electronics", 35, InventoryStatus.INSTOCK, 3));
        products.add(new Product(1028, "tx125ck42", "Yoga Mat", "Product Description", "yoga-mat.jpg", 20,
                "Fitness", 15, InventoryStatus.INSTOCK, 5));
        products.add(new Product(1029, "gwuby345v", "Yoga Set", "Product Description", "yoga-set.jpg", 20,
                "Fitness", 25, InventoryStatus.INSTOCK, 8));

    }

    public List<Product> getProducts() {
        return new ArrayList<>(products);
    }

    public List<Product> getProducts(int size) {

        if (size > products.size()) {
            Random rand = new Random();

            List<Product> randomList = new ArrayList<>();
            for (int i = 0; i < size; i++) {
                int randomIndex = rand.nextInt(products.size());
                randomList.add(products.get(randomIndex));
            }

            return randomList;
        }

        else {
            return new ArrayList<>(products.subList(0, size));
        }

    }

    public List<Product> getClonedProducts(int size) {
        List<Product> results = new ArrayList<>();
        List<Product> originals = getProducts(size);
        for (Product original : originals) {
            results.add(original.clone());
        }

        // make sure to have unique codes
        for (Product product : results) {
            product.setCode(UUID.randomUUID().toString().replace("-", "").substring(0, 8));
        }

        return results;
    }
}