FMWK-443 Add configuration flag writeSortedMaps

src/main/java/org/springframework/data/aerospike/config/AerospikeDataSettings.java

@@ -37,4 +37,6 @@ public class AerospikeDataSettings {
     // Define how @Id fields (primary keys) and Map keys are stored: false - always as String,
     // true - preserve original type if supported
     boolean keepOriginalKeyTypes = false;
+    // Define how Maps are written: true - as TreeMaps (default), false - as HashMaps
+    boolean writeTreeMaps = true;
 }

src/main/java/org/springframework/data/aerospike/convert/MappingAerospikeWriteConverter.java

@@ -37,10 +37,12 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.TreeMap;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import static com.aerospike.client.ResultCode.OP_NOT_APPLICABLE;
@@ -157,7 +159,12 @@ private void convertToAerospikeWriteData(Object source, AerospikeWriteData data)
 
     private Map<String, Object> convertProperties(TypeInformation<?> type, AerospikePersistentEntity<?> entity,
                                                   ConvertingPropertyAccessor<?> accessor, boolean isCustomType) {
-        Map<String, Object> target = new TreeMap<>();
+        Map<String, Object> target;
+        if (settings.isWriteTreeMaps()) {
+            target = new TreeMap<>();
+        } else {
+            target = new HashMap<>();
+        }
         typeMapper.writeType(type, target);
         entity.doWithProperties((PropertyHandler<AerospikePersistentProperty>) property -> {
 
@@ -234,10 +241,16 @@ protected Map<Object, Object> convertMap(final Map<Object, Object> source, final
         Assert.notNull(source, "Given map must not be null!");
         Assert.notNull(type, "Given type must not be null!");
 
-        return source.entrySet().stream().collect(TreeMap::new, (m, e) -> {
+        Supplier<Map<Object, Object>> mapSupplier;
+        if (settings.isWriteTreeMaps()) {
+            mapSupplier = TreeMap::new;
+        } else {
+            mapSupplier = HashMap::new;
+        }
+        return source.entrySet().stream().collect(mapSupplier, (m, e) -> {
             Object key = e.getKey();
             Object value = e.getValue();
-            if (key == null) {
+            if (key == null && settings.isWriteTreeMaps()) {
                 throw new UnsupportedOperationException("Key of a map cannot be null");
             }
 
@@ -261,7 +274,7 @@ protected Map<Object, Object> convertMap(final Map<Object, Object> source, final
             Object convertedValue = getValueToWrite(value, type.getMapValueType());
             if (simpleKey instanceof byte[]) simpleKey = ByteBuffer.wrap((byte[]) simpleKey);
             m.put(simpleKey, convertedValue);
-        }, TreeMap::putAll);
+        }, Map::putAll);
     }
 
     private Map<String, Object> convertCustomType(Object source, TypeInformation<?> type) {