Use UUID toString representation when converting org.bson.Document into a json String.

This commit switches the rendering of UUID values to their toString format when printing org.bson.Document to json via the DocumentToString converter.

This will move the resulting representation from {"$binary": "QUK3ZihZ9cdhWjTf5TZqrw==", "$type": "03"} to 480971b0-7160-4120-acd0-6fd6b82418ad which is the more natural variant within Java applications.

The conversion only applies on read in cases where an entire document eg. a composite id, is mapped to a String property of the domain model.

Closes #3546.
Original pull request: #3551.

Author: christophstrobl

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

@@ -27,14 +27,18 @@
 import java.util.Collection;
 import java.util.Currency;
 import java.util.List;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.bson.BsonReader;
 import org.bson.BsonTimestamp;
+import org.bson.BsonWriter;
 import org.bson.Document;
-import org.bson.UuidRepresentation;
 import org.bson.codecs.Codec;
-import org.bson.internal.CodecRegistryHelper;
+import org.bson.codecs.DecoderContext;
+import org.bson.codecs.EncoderContext;
+import org.bson.codecs.configuration.CodecRegistries;
 import org.bson.types.Binary;
 import org.bson.types.Code;
 import org.bson.types.Decimal128;
@@ -240,9 +244,23 @@ enum DocumentToStringConverter implements Converter<Document, String> {
 
 		INSTANCE;
 
-		private final Codec<Document> codec = CodecRegistryHelper
-				.createRegistry(MongoClientSettings.getDefaultCodecRegistry(), UuidRepresentation.JAVA_LEGACY)
-				.get(Document.class);
+		private final Codec<Document> codec = CodecRegistries.fromRegistries(CodecRegistries.fromCodecs(new Codec<UUID>() {
+
+			@Override
+			public void encode(BsonWriter writer, UUID value, EncoderContext encoderContext) {
+				writer.writeString(value.toString());
+			}
+
+			@Override
+			public Class<UUID> getEncoderClass() {
+				return UUID.class;
+			}
+
+			@Override
+			public UUID decode(BsonReader reader, DecoderContext decoderContext) {
+				throw new IllegalStateException("decode not supported");
+			}
+		}), MongoClientSettings.getDefaultCodecRegistry()).get(Document.class);
 
 		@Override
 		public String convert(Document source) {

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MongoConvertersUnitTests.java

@@ -22,14 +22,14 @@
 import java.time.Instant;
 import java.time.temporal.ChronoUnit;
 import java.util.Currency;
+import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
 import org.assertj.core.data.TemporalUnitLessThanOffset;
 import org.bson.BsonTimestamp;
 import org.bson.Document;
 import org.junit.jupiter.api.Test;
-
 import org.springframework.core.convert.support.ConfigurableConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.data.geo.Box;
@@ -42,6 +42,7 @@
 import org.springframework.data.mongodb.core.convert.MongoConverters.BigDecimalToStringConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.BsonTimestampToInstantConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.CurrencyToStringConverter;
+import org.springframework.data.mongodb.core.convert.MongoConverters.DocumentToStringConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.IntegerToAtomicIntegerConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.LongToAtomicLongConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.StringToBigDecimalConverter;
@@ -173,4 +174,12 @@ public void convertsUrisToString() {
 		assertThat(conversionService.convert(URI.create("/segment"), String.class)).isEqualTo("/segment");
 		assertThat(conversionService.convert("/segment", URI.class)).isEqualTo(URI.create("/segment"));
 	}
+
+	@Test // GH-3546
+	void convertsDocumentWithUUidToString() {
+
+		UUID uuid = UUID.randomUUID();
+		assertThat(DocumentToStringConverter.INSTANCE.convert(new Document("_id", uuid)))
+				.isEqualTo("{\"_id\": \"" + uuid.toString() + "\"}");
+	}
 }