re-add code for type conversion article

spring-boot/src/main/java/org/baeldung/boot/config/WebConfig.java

@@ -1,6 +1,8 @@
 package org.baeldung.boot.config;
 
 import org.baeldung.boot.converter.StringToEmployeeConverter;
+import org.baeldung.boot.converter.StringToEnumConverterFactory;
+import org.baeldung.boot.converter.GenericBigDecimalConverter;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.format.FormatterRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@@ -11,5 +13,7 @@ public class WebConfig implements WebMvcConfigurer {
     @Override
     public void addFormatters(FormatterRegistry registry) {
         registry.addConverter(new StringToEmployeeConverter());
+        registry.addConverterFactory(new StringToEnumConverterFactory());
+        registry.addConverter(new GenericBigDecimalConverter());
     }
 }

spring-boot/src/main/java/org/baeldung/boot/converter/GenericBigDecimalConverter.java

@@ -0,0 +1,31 @@
+package org.baeldung.boot.converter;
+
+import com.google.common.collect.ImmutableSet;
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.converter.GenericConverter;
+import java.math.BigDecimal;
+import java.util.Set;
+public class GenericBigDecimalConverter implements GenericConverter {
+   @Override
+   public Set<ConvertiblePair> getConvertibleTypes () {
+        ConvertiblePair[] pairs = new ConvertiblePair[] {
+               new ConvertiblePair(Number.class, BigDecimal.class),
+               new ConvertiblePair(String.class, BigDecimal.class)};
+        return ImmutableSet.copyOf(pairs);
+   }
+    @Override
+   public Object convert (Object source, TypeDescriptor sourceType,
+                          TypeDescriptor targetType) {
+       if (sourceType.getType() == BigDecimal.class) {
+           return source;
+       }
+        if(sourceType.getType() == String.class) {
+           String number = (String) source;
+           return new BigDecimal(number);
+       } else {
+           Number number = (Number) source;
+           BigDecimal converted = new BigDecimal(number.doubleValue());
+           return converted.setScale(2, BigDecimal.ROUND_HALF_EVEN);
+       }
+   }
+}

spring-boot/src/main/java/org/baeldung/boot/converter/StringToEmployeeConverter.java

@@ -9,8 +9,6 @@ public class StringToEmployeeConverter implements Converter<String, Employee> {
   @Override
   public Employee convert(String from) {
       String[] data = from.split(",");
-      return new Employee(
-        Long.parseLong(data[0]), 
-        Double.parseDouble(data[1]));
+      return new Employee(Long.parseLong(data[0]), Double.parseDouble(data[1]));
   }
 }

spring-boot/src/main/java/org/baeldung/boot/converter/StringToEnumConverterFactory.java

@@ -0,0 +1,30 @@
+package org.baeldung.boot.converter;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.core.convert.converter.ConverterFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class StringToEnumConverterFactory 
+  implements ConverterFactory<String, Enum> {
+ 
+    private static class StringToEnumConverter<T extends Enum> 
+      implements Converter<String, T> {
+ 
+        private Class<T> enumType;
+ 
+        public StringToEnumConverter(Class<T> enumType) {
+            this.enumType = enumType;
+        }
+ 
+        public T convert(String source) {
+            return (T) Enum.valueOf(this.enumType, source.trim());
+        }
+    }
+ 
+    @Override
+    public <T extends Enum> Converter<String, T> getConverter(
+      Class<T> targetType) {
+        return new StringToEnumConverter(targetType);
+    }
+}

spring-boot/src/test/java/org/baeldung/converter/CustomConverterIntegrationTest.java

@@ -43,7 +43,7 @@ public class CustomConverterIntegrationTest {
 
     @Test
     public void whenConvertingToBigDecimalUsingGenericConverter_thenSuccess() {
-        assertThat(conversionService.convert(Integer.valueOf(11), BigDecimal.class)).isEqualTo(BigDecimal.valueOf(11.00).setScale(0, BigDecimal.ROUND_HALF_EVEN));
+        assertThat(conversionService.convert(Integer.valueOf(11), BigDecimal.class)).isEqualTo(BigDecimal.valueOf(11.00).setScale(2, BigDecimal.ROUND_HALF_EVEN));
         assertThat(conversionService.convert(Double.valueOf(25.23), BigDecimal.class)).isEqualByComparingTo(BigDecimal.valueOf(Double.valueOf(25.23)));
         assertThat(conversionService.convert("2.32", BigDecimal.class)).isEqualTo(BigDecimal.valueOf(2.32));
     }