refactor: improve data identifier map structure, fix #492

common/src/main/java/net/william278/husksync/data/DataHolder.java

@@ -31,7 +31,10 @@ public interface DataHolder {
     Map<Identifier, Data> getData();
 
     default Optional<? extends Data> getData(@NotNull Identifier id) {
-        return getData().entrySet().stream().filter(e -> e.getKey().equals(id)).map(Map.Entry::getValue).findFirst();
+        if (getData().containsKey(id)) {
+            return Optional.of(getData().get(id));
+        }
+        return Optional.empty();
     }
 
     default void setData(@NotNull Identifier identifier, @NotNull Data data) {

common/src/main/java/net/william278/husksync/data/DataSnapshot.java

@@ -406,7 +406,9 @@ public class DataSnapshot {
             return deserialized.entrySet().stream()
                     .collect(Collectors.toMap(
                             entry -> entry.getKey().toString(),
-                            entry -> plugin.serializeData(entry.getKey(), entry.getValue())
+                            entry -> plugin.serializeData(entry.getKey(), entry.getValue()),
+                            (a, b) -> a,
+                            HashMap::new
                     ));
         }
 

common/src/main/java/net/william278/husksync/data/Identifier.java

@@ -38,7 +38,7 @@ import java.util.stream.Stream;
  * Identifiers of different types of {@link Data}s
  */
 @Getter
-public class Identifier {
+public class Identifier implements Comparable<Identifier> {
 
     // Namespace for built-in identifiers
     private static final @KeyPattern String DEFAULT_NAMESPACE = "husksync";
@@ -276,6 +276,14 @@ public class Identifier {
         return Map.entry(getKeyValue(), enabledByDefault);
     }
 
+    // Comparable; always sort this Identifier after any dependencies
+    @Override
+    public int compareTo(@NotNull Identifier o) {
+        if (this.dependsOn(o)) return 1;
+        if (o.dependsOn(this)) return -1;
+        return this.key.compareTo(o.key);
+    }
+
     /**
      * Compares two identifiers based on their dependencies.
      * <p>

common/src/main/java/net/william278/husksync/data/UserDataHolder.java

@@ -26,7 +26,9 @@ import org.jetbrains.annotations.NotNull;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.TreeMap;
 import java.util.logging.Level;
+import java.util.stream.Collectors;
 
 /**
  * A holder of data in the form of {@link Data}s, which can be synced
@@ -46,7 +48,11 @@ public interface UserDataHolder extends DataHolder {
                 .filter(Identifier::isEnabled)
                 .map(id -> Map.entry(id, getData(id)))
                 .filter(data -> data.getValue().isPresent())
-                .collect(HashMap::new, (map, data) -> map.put(data.getKey(), data.getValue().get()), HashMap::putAll);
+                .collect(Collectors.toMap(
+                        Map.Entry::getKey,
+                        entry -> entry.getValue().get(),
+                        (a, b) -> a, HashMap::new
+                ));
     }
 
     /**