Replace internal @Nullable with JSpecify @Nullable

gradle/libs.versions.toml

@@ -2,6 +2,7 @@
 junit = "5.10.0"
 
 [libraries]
+jspecify-annotations = { group = "org.jspecify", name = "jspecify", version = "1.0.0" }
 junit-jupiter-api = { group = "org.junit.jupiter", name = "junit-jupiter-api", version.ref = "junit" }
 junit-jupiter-engine = { group = "org.junit.jupiter", name = "junit-jupiter-engine", version.ref = "junit" }
 junit-jupiter-params = { group = "org.junit.jupiter", name = "junit-jupiter-params", version.ref = "junit" }

helios/build.gradle.kts

@@ -6,6 +6,8 @@ plugins {
 }
 
 dependencies {
+    compileOnly(libs.jspecify.annotations)
+
     testImplementation(libs.junit.jupiter.api)
     testImplementation(libs.junit.jupiter.params)
     testRuntimeOnly(libs.junit.jupiter.engine)

helios/src/main/java/me/sparky983/helios/Absent.java

@@ -5,7 +5,7 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
-import me.sparky983.helios.annotations.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * An {@code Optional} that contains no value.
@@ -14,7 +14,7 @@
  * @since 0.1.0
  * @helios.apiNote This class should not be constructed directly. Use {@link #absent()} instead.
  */
-public record Absent<T extends Object>() implements Optional<T> {
+public record Absent<T>() implements Optional<T> {
   static final Absent<?> ABSENT = new Absent<>();
 
   @Override
@@ -85,14 +85,14 @@ public T expect(final String message) {
   }
 
   @Override
-  public <M extends Object> Optional<M> map(final Function<? super T, ? extends M> mapper) {
+  public <M> Optional<M> map(final Function<? super T, ? extends M> mapper) {
     Objects.requireNonNull(mapper, "mapper cannot be null");
 
     return Optional.absent();
   }
 
   @Override
-  public <M extends Object> Optional<M> flatMap(
+  public <M> Optional<M> flatMap(
       final Function<? super T, ? extends Optional<? extends M>> mapper) {
     Objects.requireNonNull(mapper, "mapper cannot be null");
 

helios/src/main/java/me/sparky983/helios/Optional.java

@@ -5,7 +5,7 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import me.sparky983.helios.annotations.Experimental;
-import me.sparky983.helios.annotations.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * An immutable container which may contain a non-null value.
@@ -231,7 +231,7 @@
  * }
  * }
  */
-public sealed interface Optional<T extends Object> permits Present, Absent {
+public sealed interface Optional<T> permits Present, Absent {
   /**
    * Returns a present {@code Optional} containing the given value.
    *
@@ -240,7 +240,7 @@ public sealed interface Optional<T extends Object> permits Present, Absent {
    * @param <T> the type of the value
    * @throws NullPointerException if the value is {@code null}.
    */
-  static <T extends Object> Optional<T> present(final T value) {
+  static <T> Optional<T> present(final T value) {
     return new Present<>(value);
   }
 
@@ -254,7 +254,7 @@ static <T extends Object> Optional<T> present(final T value) {
    * @helios.implNote This method returns a singleton instance of {@link Absent}.
    */
   @SuppressWarnings("unchecked")
-  static <T extends Object> Optional<T> absent() {
+  static <T> Optional<T> absent() {
     return (Absent<T>) Absent.ABSENT;
   }
 
@@ -275,7 +275,7 @@ static <T extends Object> Optional<T> absent() {
    * Optional<String> optional = Optional.fromNullable(map.get("key"));
    * }
    */
-  static <T extends Object> Optional<T> fromNullable(final @Nullable T value) {
+  static <T> Optional<T> fromNullable(final @Nullable T value) {
     if (value != null) {
       return present(value);
     } else {
@@ -303,7 +303,7 @@ static <T extends Object> Optional<T> fromNullable(final @Nullable T value) {
    * }
    */
   @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
-  static <T extends Object> Optional<T> from(final java.util.Optional<T> optional) {
+  static <T> Optional<T> from(final java.util.Optional<T> optional) {
     return optional.map(Optional::present).orElse(Optional.absent());
   }
 
@@ -485,7 +485,7 @@ static <T extends Object> Optional<T> from(final java.util.Optional<T> optional)
    * assert absent.map(n -> n * 2).isAbsent();
    * }
    */
-  <M extends Object> Optional<M> map(Function<? super T, ? extends M> mapper);
+  <M> Optional<M> map(Function<? super T, ? extends M> mapper);
 
   /**
    * If this {@code Optional} is present, returns the result of applying the given mapper to the
@@ -508,8 +508,7 @@ static <T extends Object> Optional<T> from(final java.util.Optional<T> optional)
    *     .flatMap(user -> user.findRepository("helios"));
    * }
    */
-  <M extends Object> Optional<M> flatMap(
-      Function<? super T, ? extends Optional<? extends M>> mapper);
+  <M> Optional<M> flatMap(Function<? super T, ? extends Optional<? extends M>> mapper);
 
   /**
    * If this {@code Optional} is present and the value matches the given predicate, returns this

helios/src/main/java/me/sparky983/helios/Present.java

@@ -14,7 +14,7 @@
  * @helios.apiNote This class should not be constructed directly and is only public for pattern
  * matching. Use {@link #present(Object)} instead.
  */
-public record Present<T extends Object>(T value) implements Optional<T> {
+public record Present<T>(T value) implements Optional<T> {
   /**
    * Constructs a new {@code Present} {@code Optional} with the given value.
    *
@@ -83,7 +83,7 @@ public T expect(final String message) {
   }
 
   @Override
-  public <M extends Object> Optional<M> map(final Function<? super T, ? extends M> mapper) {
+  public <M> Optional<M> map(final Function<? super T, ? extends M> mapper) {
     Objects.requireNonNull(mapper, "mapper cannot be null");
 
     final var mappedValue =
@@ -94,7 +94,7 @@ public <M extends Object> Optional<M> map(final Function<? super T, ? extends M>
 
   @SuppressWarnings("unchecked")
   @Override
-  public <M extends Object> Optional<M> flatMap(
+  public <M> Optional<M> flatMap(
       final Function<? super T, ? extends Optional<? extends M>> mapper) {
     Objects.requireNonNull(mapper, "mapper cannot be null");
 

helios/src/main/java/module-info.java

@@ -10,6 +10,7 @@
 @Experimental // 0.x.y
 module me.sparky983.helios {
   requires static java.compiler; // for Javadocs
+  requires static org.jspecify;
 
   exports me.sparky983.helios;
 }