Default nullable implementation

src/main/java/it/cavallium/data/generator/NativeNullable.java

@@ -7,12 +7,14 @@ public interface NativeNullable<T> {
 
 	boolean isEmpty();
 
-	boolean isPresent();
+	default boolean isPresent() {
+		return !isEmpty();
+	}
 
 	@NotNull
 	T orElse(@NotNull T defaultValue);
 
-	@NotNull NativeNullable<T> or(@NotNull NativeNullable<? extends T> fallback);
+	@NotNull NativeNullable<? extends T> or(@NotNull NativeNullable<? extends T> fallback);
 
 	@Nullable
 	T getNullable();

src/main/java/it/cavallium/data/generator/TypedNullable.java

@@ -1,9 +1,53 @@
 package it.cavallium.data.generator;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public interface TypedNullable<T> extends NativeNullable<T> {
 
 	@NotNull
-	T get() throws NullPointerException;
+	default T get() throws NullPointerException {
+		var value = getNullable();
+		if (value == null) {
+			throw new NullPointerException();
+		} else {
+			return value;
+		}
+	}
+
+	@Override
+	default @Nullable T getNullable(@Nullable T defaultValue) {
+		var value = getNullable();
+		return value == null ? defaultValue : value;
+	}
+
+	@Override
+	default @NotNull T orElse(@NotNull T defaultValue) {
+		var value = getNullable();
+		if (value == null) {
+			throw new NullPointerException();
+		} else {
+			return value;
+		}
+	}
+
+	@Override
+	default @NotNull NativeNullable<? extends T> or(@NotNull NativeNullable<? extends T> fallback) {
+		var value = getNullable();
+		if (value == null) {
+			return fallback;
+		} else {
+			return this;
+		}
+	}
+
+	@Override
+	default boolean isPresent() {
+		return getNullable() != null;
+	}
+
+	@Override
+	default boolean isEmpty() {
+		return getNullable() == null;
+	}
 }