Add @ConfigConstructor

res/plugin.yml

@@ -1,6 +1,6 @@
 name: RedLib
 main: redempt.redlib.RedLib
-version: 2023-12-22 19:59
+version: 2024-02-13 00:41
 author: Redempt
 api-version: 1.13
 load: STARTUP

src/redempt/redlib/config/annotations/ConfigConstructor.java

@@ -0,0 +1,14 @@
+package redempt.redlib.config.annotations;
+
+import java.lang.annotation.*;
+
+/**
+ * Denotes a constructor which can be used to initialize the object from config.
+ * Parameter names in the constructor must match field names in the class.
+ */
+@Inherited
+@Target(ElementType.CONSTRUCTOR)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface ConfigConstructor {
+}

src/redempt/redlib/config/conversion/ObjectConverter.java

@@ -30,13 +30,13 @@ public static <T> TypeConverter<T> create(ConversionManager manager, ConfigType<
 		if (type.getType().isInterface() || Modifier.isAbstract(type.getType().getModifiers())) {
 			throw new IllegalStateException("Cannot automatically convert abstract classe or interface " + type.getType());
 		}
-		Instantiator instantiator = Instantiator.getInstantiator(type.getType());
 		FieldSummary summary = FieldSummary.getFieldSummary(manager, type.getType(), false);
+		Instantiator instantiator = Instantiator.getInstantiator(type.getType());
 		return new TypeConverter<T>() {
 			@Override
 			public T loadFrom(DataHolder section, String path, T currentValue) {
 				DataHolder newSection = path == null ? section : section.getSubsection(path);
-				List<Object> objs = new ArrayList<>();
+				List<Object> objs = new ArrayList<>(summary.getFields().size());
 				for (ConfigField field : summary.getFields()) {
 					Object value = summary.getConverters().get(field).loadFrom(newSection, field.getName(), null);
 					objs.add(value);

src/redempt/redlib/config/instantiation/ConstructorInstantiator.java

@@ -1,38 +1,36 @@
 package redempt.redlib.config.instantiation;
 
-import redempt.redlib.config.ConfigManager;
+import redempt.redlib.config.ConfigField;
 import redempt.redlib.config.ConversionManager;
 import redempt.redlib.config.annotations.ConfigPath;
-import redempt.redlib.config.data.DataHolder;
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Parameter;
-import java.util.Arrays;
-import java.util.List;
+import java.util.*;
+import java.util.stream.IntStream;
 
 /**
  * An instantiator used for record types which passes in all necessary fields
  * @author Redempt
  */
 public class ConstructorInstantiator implements Instantiator {
-	
+
 	/**
 	 * Attempts to create an Instantiator for a record type, or a class which has a constructor taking all its fields
 	 * in the same order they appear in the class
 	 * @param clazz The class to create an Instantiator for
 	 * @param <T> The type
 	 * @return An Instantiator
 	 */
-	public static <T> Instantiator create(Class<?> clazz) {
+	public static <T> Instantiator createDefault(Class<?> clazz) {
 		try {
 			Field[] fields = clazz.getDeclaredFields();
 			Constructor<?> constructor = clazz.getDeclaredConstructor(Arrays.stream(fields).map(Field::getType).toArray(Class<?>[]::new));
 			return new ConstructorInstantiator(constructor);
 		} catch (NoSuchMethodException e) {
-			e.printStackTrace();
-			return null;
+			throw new IllegalStateException("Class '" + clazz.getName() + "' does not have a constructor that takes all of its fields in order");
 		}
 	}
 
@@ -43,6 +41,11 @@ private ConstructorInstantiator(Constructor<?> constructor) {
 		this.constructor = constructor;
 		params = constructor.getParameters();
 	}
+
+	private ConstructorInstantiator(Constructor<?> constructor, int[] indices) {
+		this.constructor = constructor;
+		params = constructor.getParameters();
+	}
 
 	/**
 	 * Instantiates a new object using its constructor

src/redempt/redlib/config/instantiation/Instantiator.java

@@ -1,11 +1,13 @@
 package redempt.redlib.config.instantiation;
 
-import redempt.redlib.config.ConfigManager;
 import redempt.redlib.config.ConversionManager;
+import redempt.redlib.config.annotations.ConfigConstructor;
 import redempt.redlib.config.annotations.ConfigMappable;
-import redempt.redlib.config.data.DataHolder;
 
+import java.lang.reflect.Constructor;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * A utility to instantiate objects from values loaded from config
@@ -25,11 +27,12 @@ public static boolean isRecord(Class<?> clazz) {
 	 */
 	public static Instantiator getInstantiator(Class<?> clazz) {
 		if (isRecord(clazz)) {
-			return ConstructorInstantiator.create(clazz);
+			return ConstructorInstantiator.createDefault(clazz);
 		}
 		if (clazz.isAnnotationPresent(ConfigMappable.class)) {
-			return new EmptyInstantiator();
-		}
+			Optional<Constructor<?>> constructor = Arrays.stream(clazz.getConstructors()).filter(c -> c.isAnnotationPresent(ConfigConstructor.class)).findFirst();
+            return constructor.map(value -> ConstructorInstantiator.createDefault(clazz)).orElseGet(EmptyInstantiator::new);
+        }
 		throw new IllegalArgumentException("Cannot create instantiator for class which is not a record type and not annotated with ConfigMappable (" + clazz + ")");
 	}