Use index instead of iterator to map position and map keys for updates.

This commit removes usage of the iterator and replaces map key and positional parameter mappings with an index based token lookup.

Closes #3921
Original pull request: #3930.

Author: christophstrobl

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

@@ -1411,6 +1411,14 @@ public KeyMapper(String key,
 				this.currentIndex = 0;
 			}
 
+			String nextToken() {
+				return pathParts.get(currentIndex+1);
+			}
+
+			boolean hasNexToken() {
+				return pathParts.size() > currentIndex+1;
+			}
+
 			/**
 			 * Maps the property name while retaining potential positional operator {@literal $}.
 			 *
@@ -1420,31 +1428,25 @@ public KeyMapper(String key,
 			protected String mapPropertyName(MongoPersistentProperty property) {
 
 				StringBuilder mappedName = new StringBuilder(PropertyToFieldNameConverter.INSTANCE.convert(property));
+				if(!hasNexToken()) {
+					return mappedName.toString();
+				}
 
-				boolean inspect = iterator.hasNext();
-
-				while (inspect) {
-
-					String partial = iterator.next();
-					currentIndex++;
-
-					boolean isPositional = isPositionalParameter(partial) && property.isCollectionLike();
-					if (property.isMap() && currentPropertyRoot.equals(partial) && iterator.hasNext()) {
-						partial = iterator.next();
-						currentIndex++;
-					}
-
-					if (isPositional || property.isMap() && !currentPropertyRoot.equals(partial)) {
-						mappedName.append(".").append(partial);
-					}
+				String nextToken = nextToken();
+				if(isPositionalParameter(nextToken)) {
 
-					inspect = isPositional && iterator.hasNext();
+					mappedName.append(".").append(nextToken);
+					currentIndex+=2;
+					return mappedName.toString();
 				}
 
-				if (currentIndex + 1 < pathParts.size()) {
-					currentIndex++;
-					currentPropertyRoot = pathParts.get(currentIndex);
+				if(property.isMap()) {
+
+					mappedName.append(".").append(nextToken);
+					currentIndex+=2;
+					return mappedName.toString();
 				}
+				currentIndex++;
 				return mappedName.toString();
 			}
 

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

@@ -1309,6 +1309,36 @@ void updateListWithDocuRefOnProperty() {
 		assertThat(mappedUpdate).isEqualTo(new org.bson.Document("$set",new org.bson.Document("customers", Arrays.asList("c-name"))));
 	}
 
+	@Test // GH-3921
+	void mapNumericKeyInPathHavingComplexMapValyeTypes() {
+
+		Update update = new Update().set("testInnerData.testMap.1.intValue", "4");
+		Document mappedUpdate = mapper.getMappedObject(update.getUpdateObject(),
+				context.getPersistentEntity(TestData.class));
+
+		assertThat(mappedUpdate).isEqualTo(new org.bson.Document("$set",new org.bson.Document("testInnerData.testMap.1.intValue","4")));
+	}
+
+	@Test // GH-3921
+	void mapNumericKeyInPathNotMatchingExistingProperties() {
+
+		Update update = new Update().set("testInnerData.imaginaryMap.1.nonExistingProperty", "4");
+		Document mappedUpdate = mapper.getMappedObject(update.getUpdateObject(),
+				context.getPersistentEntity(TestData.class));
+
+		assertThat(mappedUpdate).isEqualTo(new org.bson.Document("$set",new org.bson.Document("testInnerData.imaginaryMap.1.noExistingProperty","4")));
+	}
+
+	@Test // GH-3921
+	void mapNumericKeyInPathPartiallyMatchingExistingProperties() {
+
+		Update update = new Update().set("testInnerData.testMap.1.nonExistingProperty.2.someValue", "4");
+		Document mappedUpdate = mapper.getMappedObject(update.getUpdateObject(),
+				context.getPersistentEntity(TestData.class));
+
+		assertThat(mappedUpdate).isEqualTo(new org.bson.Document("$set",new org.bson.Document("testInnerData.testMap.1.nonExistingProperty.2.someValue","4")));
+	}
+
 	static class DomainTypeWrappingConcreteyTypeHavingListOfInterfaceTypeAttributes {
 		ListModelWrapper concreteTypeWithListAttributeOfInterfaceType;
 	}
@@ -1710,4 +1740,20 @@ static class WithDocumentReference {
 		private List<Sample> samples;
 	}
 
+	@Data
+	private static class TestData {
+		@Id
+		private String id;
+		private TestInnerData testInnerData;
+	}
+
+	@Data
+	private static class TestInnerData {
+		private Map<Integer, TestValue> testMap;
+	}
+
+	@Data
+	private static class TestValue {
+		private int intValue;
+	}
 }