1 files changed, 55 insertions, 0 deletions
diff --git a/src/main/java/io/github/moulberry/notenoughupdates/util/AsyncDependencyLoader.java b/src/main/java/io/github/moulberry/notenoughupdates/util/AsyncDependencyLoader.java
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index 00000000..37b0a187
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+++ b/src/main/java/io/github/moulberry/notenoughupdates/util/AsyncDependencyLoader.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2022 NotEnoughUpdates contributors
+ *
+ * This file is part of NotEnoughUpdates.
+ *
+ * NotEnoughUpdates is free software: you can redistribute it
+ * and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * NotEnoughUpdates is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with NotEnoughUpdates. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package io.github.moulberry.notenoughupdates.util;
+
+import com.google.common.base.Objects;
+
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+public interface AsyncDependencyLoader<T> {
+
+	Optional<T> peekValue();
+
+	public static <R, T> AsyncDependencyLoader<T> withObjectIdentity(
+		Supplier<R> supplier,
+		Function<R, CompletableFuture<T>> generator
+	) {
+		return new AsyncDependencyLoaderImpl<>(supplier, generator, (a, b) -> a != b);
+	}
+
+	public static <R, T> AsyncDependencyLoader<T> withEqualsInvocation(
+		Supplier<R> supplier,
+		Function<R, CompletableFuture<T>> generator
+	) {
+		return new AsyncDependencyLoaderImpl<>(supplier, generator, (a, b) -> !Objects.equal(a, b));
+	}
+
+	public static <R, T> AsyncDependencyLoader<T> withEqualityFunction(
+		Supplier<R> supplier,
+		Function<R, CompletableFuture<T>> generator,
+		BiFunction<R, R, Boolean> isEqual
+	) {
+		return new AsyncDependencyLoaderImpl<>(supplier, generator, (a, b) -> !isEqual.apply(a, b));
+	}
+}