Have downloadable shopping list

src/main/java/com/mousetech/gourmetj/utils/YamlShoppingList.java

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+package com.mousetech.gourmetj.utils;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintWriter;
+import java.util.List;
+
+import org.apache.commons.lang3.StringUtils;
+import org.primefaces.model.ByteArrayContent;
+import org.primefaces.model.StreamedContent;
+
+import com.mousetech.gourmetj.ShopIngredient;
+
+/**
+ * Construct a Primefaces file output content for an ingredient
+ * list in YAML format.
+ * 
+ * @author timh
+ * @since Jan 15, 2022
+ */
+
+public class YamlShoppingList {
+
+	public static StreamedContent createDownload(
+			List<ShopIngredient> ingredientList) {
+		ByteArrayOutputStream ary = new ByteArrayOutputStream();
+		PrintWriter wtr = new PrintWriter(ary);
+		wtr.println("---");
+		formatContent(wtr, ingredientList);
+		wtr.close();
+		byte[] bas = ary.toByteArray();
+
+		StreamedContent dlList = new ByteArrayContent(bas,
+				"text/text", "shopping_list.yml");
+		return dlList;
+	}
+
+	/**
+	 * Output line items in the ingredient list with topics for
+	 * each Shopping Category.
+	 * 
+	 * @param wtr            Output Writer
+	 * @param ingredientList Ingredient list to output.
+	 */
+	private static void formatContent(PrintWriter wtr,
+			List<ShopIngredient> ingredientList) {
+		String oldShopcat = null;
+		for (ShopIngredient ing : ingredientList) {
+			String newShopcat = ing.getShopCat();
+			if (StringUtils.isBlank(newShopcat)) {
+				newShopcat = "Unassigned";
+			}
+			if (!StringUtils.equals(newShopcat, oldShopcat)) {
+				wtr.println(newShopcat + ":");
+				oldShopcat = newShopcat;
+			}
+			wtr.print("  -  ");
+			String displa = ing.getDisplayAmount();
+			wtr.print(displa);
+			if (!displa.isBlank()) {
+				wtr.print(' ');
+			}
+			String unit = ing.getUnit();
+			if (StringUtils.isNotBlank(unit)) {
+				wtr.print(unit);
+				wtr.print(' ');
+			}
+			wtr.println(ing.getItem());
+		}
+	}
+
+}