Expose the empty, immutable ConfigNode and ConfigList

Steanky · Mar 10, 2024 · ad668ad · ad668ad
1 parent 927e5d8
commit ad668ad
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Showing 4 changed files with 19 additions and 8 deletions.
diff --git a/...lene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigContainers.java b/...lene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigContainers.java
@@ -194,7 +194,7 @@ public Set<Entry<String, ConfigElement>> entrySet() {
         }
     }
 
-    private static final class ConfigListView extends AbstractConfigList implements Immutable, RandomAccess {
+    static final class ConfigListView extends AbstractConfigList implements Immutable, RandomAccess {
         private final ConfigList underlying;
 
         private ConfigListView(ConfigList underlying) {
@@ -232,8 +232,8 @@ public int size() {
         }
     }
 
-    private static final class EmptyImmutableConfigList extends AbstractConfigList implements Immutable, RandomAccess {
-        private static final ConfigList INSTANCE = new EmptyImmutableConfigList();
+    static final class EmptyImmutableConfigList extends AbstractConfigList implements Immutable, RandomAccess {
+        static final ConfigList INSTANCE = new EmptyImmutableConfigList();
 
         private EmptyImmutableConfigList() {
 
@@ -270,8 +270,8 @@ public int size() {
         }
     }
 
-    private static final class EmptyImmutableConfigNode extends AbstractConfigNode implements Immutable {
-        private static final ConfigNode INSTANCE = new EmptyImmutableConfigNode();
+    static final class EmptyImmutableConfigNode extends AbstractConfigNode implements Immutable {
+        static final ConfigNode INSTANCE = new EmptyImmutableConfigNode();
 
         private EmptyImmutableConfigNode() {
         }
@@ -330,7 +330,7 @@ public Set<Entry<String, ConfigElement>> entrySet() {
         }
     }
 
-    private static final class ImmutableConfigNode extends AbstractConfigNode implements Immutable {
+    static final class ImmutableConfigNode extends AbstractConfigNode implements Immutable {
         private final Map<String, ConfigElement> map;
 
         private ImmutableConfigNode(Map<String, ConfigElement> trusted) {
@@ -380,7 +380,7 @@ public Set<Entry<String, ConfigElement>> entrySet() {
         }
     }
 
-    private static final class ImmutableConfigList extends AbstractConfigList implements Immutable, RandomAccess {
+    static final class ImmutableConfigList extends AbstractConfigList implements Immutable, RandomAccess {
         private final ConfigElement[] elements;
 
         private ImmutableConfigList(ConfigElement[] elements) {

diff --git a/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigList.java b/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigList.java
@@ -12,6 +12,11 @@
  * Represents an ordered collection of {@link ConfigElement} objects. ConfigList does not support null values.
  */
 public interface ConfigList extends ConfigElement, List<ConfigElement>, ConfigContainer {
+    /**
+     * The shared, immutable empty ConfigList.
+     */
+    ConfigList EMPTY = ConfigContainers.EmptyImmutableConfigList.INSTANCE;
+
     /**
      * Similarly to {@link ConfigNode#of(Object...)}, builds a new {@link ArrayConfigList} from the given object array.
      * Objects that are instances of {@link ConfigElement} will be added to the resulting list directly, whereas objects

diff --git a/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigNode.java b/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/ConfigNode.java
@@ -17,6 +17,11 @@
  * {@link ConfigPrimitive} instance containing null.</p>
  */
 public interface ConfigNode extends ConfigElement, Map<String, ConfigElement>, ConfigContainer {
+    /**
+     * The shared, immutable empty ConfigNode.
+     */
+    ConfigNode EMPTY = ConfigContainers.EmptyImmutableConfigNode.INSTANCE;
+
     /**
      * Overload of {@link ConfigNode#of(Object...)}. Returns a new, empty {@link LinkedConfigNode}.
      *

diff --git a/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/Immutable.java b/ethylene-core/src/main/java/com/github/steanky/ethylene/core/collection/Immutable.java
@@ -3,7 +3,8 @@
 /**
  * Marker interface indicating a {@link ConfigContainer} implementation is immutable; i.e. its mutating methods, like
  * {@link ConfigList#add(Object)} or {@link ConfigNode#put(Object, Object)}, will throw an exception if called, and
- * cannot change the container itself.
+ * cannot change the container itself. However, the contents may still change if there is an underlying container
+ * that is mutable.
  * <p>
  * Additionally, implementations must ensure that any sub-containers are also immutable.
  */