Add comma decimal support for input forms

Signed-off-by: Pekka Helenius <fincer89@hotmail.com>

bookstore/src/main/java/com/fjordtek/bookstore/model/Book.java

@@ -24,9 +24,6 @@ import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.Pattern;
 import javax.validation.constraints.Size;
 
-import org.springframework.format.annotation.NumberFormat;
-import org.springframework.format.annotation.NumberFormat.Style;
-
 import com.fjordtek.bookstore.annotation.CurrentYear;
 
 @Entity
@@ -143,11 +140,10 @@ public class Book {
 	private String isbn;
 
 	//////////
-	@NumberFormat(style = Style.NUMBER, pattern = "#,###.###")
 	@Column(nullable = false)
 	@Digits(
 			integer = 3, fraction = 2,
-			message = "Invalid price, possibly too many decimals"
+			message = "Invalid price value"
 			)
 	@DecimalMin(
 			value   = minPrice, message = "Too low price value. Minimum allowed: " + minPrice

bookstore/src/main/java/com/fjordtek/bookstore/web/BigDecimalPropertyEditor.java

@@ -0,0 +1,28 @@
+// Pekka Helenius <fincer89@hotmail.com>, Fjordtek 2020
+
+package com.fjordtek.bookstore.web;
+
+import java.beans.PropertyEditorSupport;
+import java.math.BigDecimal;
+
+public class BigDecimalPropertyEditor extends PropertyEditorSupport {
+
+	@Override
+	public void setAsText(String input) {
+
+		String[] decimalSeparators = {",", "."};
+
+		for (int i = 0; i < decimalSeparators.length; i++) {
+
+			// TODO count of decimal separators must be exactly 1
+			if (input.contains(decimalSeparators[i])) {
+				input = input.replace(decimalSeparators[i], ".");
+				break;
+			}
+		}
+
+		Number number = Double.parseDouble(input);
+		BigDecimal bigDecimal = BigDecimal.valueOf(number.doubleValue());
+		setValue(bigDecimal);
+	}
+}

bookstore/src/main/java/com/fjordtek/bookstore/web/BookController.java

@@ -2,6 +2,7 @@
 
 package com.fjordtek.bookstore.web;
 
+import java.math.BigDecimal;
 import java.time.Year;
 import java.util.HashMap;
 import java.util.Map;
@@ -15,6 +16,8 @@ import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.annotation.InitBinder;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -29,6 +32,14 @@ import com.fjordtek.bookstore.model.CategoryRepository;
 @Controller
 public class BookController {
 
+	/* We allow both comma and dot decimal separators
+	 * for BigDecimal data types used in Book class.
+	 */
+	@InitBinder("book")
+	public void initBinder(WebDataBinder binder) {
+		binder.registerCustomEditor(BigDecimal.class, new BigDecimalPropertyEditor());
+	}
+
 	@Autowired
 	private BookRepository       bookRepository;
 

bookstore/src/main/resources/messages.properties

@@ -25,7 +25,7 @@ book.desc.example.author     = Andrzej Sapkowski
 book.desc.example.title      = The Witcher\:\ The Lady of the Lake
 book.desc.example.isbn       = 1212121-3 or 4545454-67 or 6767676-890
 book.desc.example.year       = 1854 or 2005
-book.desc.example.price      = 17 or 123.5 or 45.67
+book.desc.example.price      = 17 or 123.5 or 45.67 or 78,43
                         
 book.error.author            = Invalid author name
 book.error.title             = Invalid title