Polishing.

Refine documentation. Simplify NumberToNumberConverter.

Author: mp911de

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoConverters.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.data.mongodb.core.convert;
 
-import static org.springframework.data.convert.ConverterBuilder.reading;
+import static org.springframework.data.convert.ConverterBuilder.*;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -47,6 +47,7 @@
 import org.bson.types.Code;
 import org.bson.types.Decimal128;
 import org.bson.types.ObjectId;
+
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.ConditionalConverter;
@@ -92,6 +93,7 @@ static Collection<Object> getConvertersToRegister() {
 
 		converters.add(BigDecimalToDecimal128Converter.INSTANCE);
 		converters.add(Decimal128ToBigDecimalConverter.INSTANCE);
+		converters.add(BigIntegerToDecimal128Converter.INSTANCE);
 
 		converters.add(URLToStringConverter.INSTANCE);
 		converters.add(StringToURLConverter.INSTANCE);
@@ -190,6 +192,17 @@ public Decimal128 convert(BigDecimal source) {
 		}
 	}
 
+	/**
+	 * @since 5.0
+	 */
+	enum BigIntegerToDecimal128Converter implements Converter<BigInteger, Decimal128> {
+		INSTANCE;
+
+		public Decimal128 convert(BigInteger source) {
+			return new Decimal128(new BigDecimal(source));
+		}
+	}
+
 	enum StringToBigDecimalConverter implements Converter<String, BigDecimal> {
 		INSTANCE;
 
@@ -413,17 +426,6 @@ public NumberToNumberConverter(Class<T> targetType) {
 			@Override
 			public T convert(Number source) {
 
-				if (targetType == Decimal128.class) {
-
-					if (source instanceof BigDecimal bigDecimal) {
-						return targetType.cast(BigDecimalToDecimal128Converter.INSTANCE.convert(bigDecimal));
-					}
-
-					if (source instanceof BigInteger bigInteger) {
-						return targetType.cast(new Decimal128(bigInteger.longValueExact()));
-					}
-				}
-
 				if (source instanceof AtomicInteger atomicInteger) {
 					return NumberUtils.convertNumberToTargetClass(atomicInteger.get(), this.targetType);
 				}

src/main/antora/modules/ROOT/pages/mongodb/mapping/custom-conversions.adoc

@@ -108,6 +108,6 @@ class MyMongoConfiguration extends AbstractMongoClientConfiguration {
 == Big Number Format
 
 MongoDB in its early days did not have support for large numeric values such as `BigDecimal`.
-In order to persist values those types got converted into their `String` representation.
-Nowadays `org.bson.types.Decimal128` offers a native solution to storing big numbers.
-Next to influencing the to be stored numeric representation via the `@Field` annotation you can configure `MongoCustomConversions` to use `Decimal128` instead of `String` via the `MongoConverterConfigurationAdapter#numericFormat(...)` or set the `mongo.numeric.format=decimal128` property.
+To persist `BigDecimal` and `BigInteger` values, Spring Data MongoDB converted values their `String` representation.
+With MongoDB Server 3.4, `org.bson.types.Decimal128` offers a native representation for `BigDecimal` and `BigInteger`.
+You can use the to the native representation by either annotating your properties with `@Field(targetType=DECIMAL128)` or by configuring the big decimal representation in `MongoCustomConversions`.

src/main/antora/modules/ROOT/pages/mongodb/mapping/mapping.adoc

@@ -165,13 +165,13 @@ calling `get()` before the actual conversion
 
 | `BigInteger`
 | converter +
-`String`
-| `{"value" : "741" }`
+`NumberDecimal`, `String`
+| `{"value" : NumberDecimal("741") }`, `{"value" : "741" }`
 
 | `BigDecimal`
 | converter +
-`String`
-| `{"value" : "741.99" }`
+`NumberDecimal`, `String`
+| `{"value" : NumberDecimal("741.99") }`, `{"value" : "741.99" }`
 
 | `URL`
 | converter