Add option to specify if empty property should not be sent to Elasticsearch.

Original Pull Request #2482
Closes #2290

Author: sothawo

src/main/java/org/springframework/data/elasticsearch/annotations/Field.java

@@ -210,4 +210,12 @@
 	 * @since 4.3
 	 */
 	boolean excludeFromSource() default false;
+
+	/**
+	 * when this field is a {{@link String}}, a {{@link java.util.Collection}} or a {{@link java.util.Map}} that is empty
+	 * this property controlls whether the empty value is sent to Elasticsearch.
+	 *
+	 * @since 5.1
+	 */
+	boolean storeEmptyValue() default true;
 }

src/main/java/org/springframework/data/elasticsearch/core/convert/MappingElasticsearchConverter.java

@@ -960,6 +960,10 @@ private void writeProperties(ElasticsearchPersistentEntity<?> entity, Persistent
 					continue;
 				}
 
+				if (!property.storeEmptyValue() && hasEmptyValue(value)) {
+					continue;
+				}
+
 				if (property.hasPropertyValueConverter()) {
 					value = propertyConverterWrite(property, value);
 					sink.set(property, value);
@@ -988,6 +992,16 @@ private void writeProperties(ElasticsearchPersistentEntity<?> entity, Persistent
 			}
 		}
 
+		private static boolean hasEmptyValue(Object value) {
+
+			if (value instanceof String s && s.isEmpty() || value instanceof Collection<?> c && c.isEmpty()
+					|| value instanceof Map<?, ?> m && m.isEmpty()) {
+				return true;
+			}
+
+			return false;
+		}
+
 		@SuppressWarnings("unchecked")
 		protected void writeProperty(ElasticsearchPersistentProperty property, Object value, MapValueAccessor sink) {
 

src/main/java/org/springframework/data/elasticsearch/core/mapping/ElasticsearchPersistentProperty.java

@@ -74,6 +74,13 @@ public interface ElasticsearchPersistentProperty extends PersistentProperty<Elas
 	 */
 	boolean storeNullValue();
 
+	/**
+	 * @return true if empty values ({{@link String}}, or {{@link java.util.Collection}} or {{@link java.util.Map}})
+	 *         should be store in Elasticsearch.
+	 * @since 5.1
+	 */
+	boolean storeEmptyValue();
+
 	/**
 	 * @return {@literal true} if this is a GeoPoint property
 	 * @since 4.1
@@ -100,7 +107,7 @@ public interface ElasticsearchPersistentProperty extends PersistentProperty<Elas
 
 	/**
 	 * @return {@literal true} if this is a property annotated with
-	 * {@link org.springframework.data.elasticsearch.annotations.IndexedIndexName}.
+	 *         {@link org.springframework.data.elasticsearch.annotations.IndexedIndexName}.
 	 * @since 5.1
 	 */
 	boolean isIndexedIndexNameProperty();

src/main/java/org/springframework/data/elasticsearch/core/mapping/SimpleElasticsearchPersistentProperty.java

@@ -82,6 +82,7 @@ public class SimpleElasticsearchPersistentProperty extends
 	private final @Nullable String annotatedFieldName;
 	@Nullable private PropertyValueConverter propertyValueConverter;
 	private final boolean storeNullValue;
+	private final boolean storeEmptyValue;
 
 	public SimpleElasticsearchPersistentProperty(Property property,
 			PersistentEntity<?, ElasticsearchPersistentProperty> owner, SimpleTypeHolder simpleTypeHolder) {
@@ -106,6 +107,7 @@ public SimpleElasticsearchPersistentProperty(Property property,
 		initPropertyValueConverter();
 
 		storeNullValue = isField && getRequiredAnnotation(Field.class).storeNullValue();
+		storeEmptyValue = isField ? getRequiredAnnotation(Field.class).storeEmptyValue() : true;
 	}
 
 	@Override
@@ -134,6 +136,11 @@ public boolean storeNullValue() {
 		return storeNullValue;
 	}
 
+	@Override
+	public boolean storeEmptyValue() {
+		return storeEmptyValue;
+	}
+
 	protected boolean hasExplicitFieldName() {
 		return StringUtils.hasText(getAnnotatedFieldName());
 	}

src/test/java/org/springframework/data/elasticsearch/core/convert/MappingElasticsearchConverterUnitTests.java

@@ -1893,6 +1893,35 @@ void shouldNotWriteIdPropertyToDocumentSourceIfConfiguredSo() throws JSONExcepti
 		assertEquals(expected, json, true);
 	}
 
+	@Test // #2290
+	@DisplayName("should respect field setting for empty properties")
+	void shouldRespectFieldSettingForEmptyProperties() throws JSONException {
+		@Language("JSON")
+		var expected = """
+				{
+					"_class": "org.springframework.data.elasticsearch.core.convert.MappingElasticsearchConverterUnitTests$EntityWithPropertiesThatMightBeEmpty",
+					"id": "42",
+					"stringToWriteWhenEmpty": "",
+					"listToWriteWhenEmpty": [],
+					"mapToWriteWhenEmpty": {}
+				}
+				""";
+		var entity = new EntityWithPropertiesThatMightBeEmpty();
+		entity.setId("42");
+		entity.setStringToWriteWhenEmpty("");
+		entity.setStringToNotWriteWhenEmpty("");
+		entity.setListToWriteWhenEmpty(emptyList());
+		entity.setListToNotWriteWhenEmpty(emptyList());
+		entity.setMapToWriteWhenEmpty(emptyMap());
+		entity.setMapToNotWriteWhenEmpty(emptyMap());
+
+		Document document = Document.create();
+		mappingElasticsearchConverter.write(entity, document);
+		String json = document.toJson();
+
+		assertEquals(expected, json, true);
+	}
+
 	// region entities
 	public static class Sample {
 		@Nullable public @ReadOnlyProperty String readOnly;
@@ -2974,6 +3003,91 @@ public void setText(@Nullable String text) {
 			this.text = text;
 		}
 	}
+
+	static class EntityWithPropertiesThatMightBeEmpty {
+		@Nullable private String id;
+
+		@Field(type = FieldType.Text)
+		@Nullable private String stringToWriteWhenEmpty;
+
+		@Field(type = FieldType.Text, storeEmptyValue = false)
+		@Nullable private String stringToNotWriteWhenEmpty;
+
+		@Field(type = FieldType.Nested)
+		@Nullable private List<String> listToWriteWhenEmpty;
+
+		@Field(type = FieldType.Nested, storeEmptyValue = false)
+		@Nullable private List<String> listToNotWriteWhenEmpty;
+
+		@Field(type = FieldType.Nested)
+		@Nullable private Map<String, String> mapToWriteWhenEmpty;
+
+		@Field(type = FieldType.Nested, storeEmptyValue = false)
+		@Nullable private Map<String, String> mapToNotWriteWhenEmpty;
+
+		@Nullable
+		public String getId() {
+			return id;
+		}
+
+		public void setId(@Nullable String id) {
+			this.id = id;
+		}
+
+		@Nullable
+		public String getStringToWriteWhenEmpty() {
+			return stringToWriteWhenEmpty;
+		}
+
+		public void setStringToWriteWhenEmpty(@Nullable String stringToWriteWhenEmpty) {
+			this.stringToWriteWhenEmpty = stringToWriteWhenEmpty;
+		}
+
+		@Nullable
+		public String getStringToNotWriteWhenEmpty() {
+			return stringToNotWriteWhenEmpty;
+		}
+
+		public void setStringToNotWriteWhenEmpty(@Nullable String stringToNotWriteWhenEmpty) {
+			this.stringToNotWriteWhenEmpty = stringToNotWriteWhenEmpty;
+		}
+
+		@Nullable
+		public List<String> getListToWriteWhenEmpty() {
+			return listToWriteWhenEmpty;
+		}
+
+		public void setListToWriteWhenEmpty(@Nullable List<String> listToWriteWhenEmpty) {
+			this.listToWriteWhenEmpty = listToWriteWhenEmpty;
+		}
+
+		@Nullable
+		public List<String> getListToNotWriteWhenEmpty() {
+			return listToNotWriteWhenEmpty;
+		}
+
+		public void setListToNotWriteWhenEmpty(@Nullable List<String> listToNotWriteWhenEmpty) {
+			this.listToNotWriteWhenEmpty = listToNotWriteWhenEmpty;
+		}
+
+		@Nullable
+		public Map<String, String> getMapToWriteWhenEmpty() {
+			return mapToWriteWhenEmpty;
+		}
+
+		public void setMapToWriteWhenEmpty(@Nullable Map<String, String> mapToWriteWhenEmpty) {
+			this.mapToWriteWhenEmpty = mapToWriteWhenEmpty;
+		}
+
+		@Nullable
+		public Map<String, String> getMapToNotWriteWhenEmpty() {
+			return mapToNotWriteWhenEmpty;
+		}
+
+		public void setMapToNotWriteWhenEmpty(@Nullable Map<String, String> mapToNotWriteWhenEmpty) {
+			this.mapToNotWriteWhenEmpty = mapToNotWriteWhenEmpty;
+		}
+	}
 	// endregion
 
 	private static String reverse(Object o) {