cn.nukkit.utils.OptionalValue Maven / Gradle / Ivy

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package cn.nukkit.utils;

import cn.nukkit.api.PowerNukkitOnly;
import cn.nukkit.api.PowerNukkitXOnly;
import cn.nukkit.api.Since;

import javax.annotation.Nullable;
import java.util.Objects;
import java.util.function.Consumer;
import java.util.function.Supplier;

@PowerNukkitXOnly
public final class OptionalValue {
    private static final OptionalValue EMPTY = new OptionalValue<>(null);

    @Nullable
    private final T value;

    OptionalValue(@Nullable T value) {
        this.value = value;
    }

    public static  OptionalValue of(T value) {
        return new OptionalValue<>(Objects.requireNonNull(value));
    }

    public static  OptionalValue ofNullable(T value) {
        return value == null ? (OptionalValue) EMPTY : of(value);
    }

    public static  OptionalValue empty() {
        return (OptionalValue) EMPTY;
    }

    public boolean isPresent() {
        return value != null;
    }

    public void ifPresent(Consumer consumer) {
        if (value != null) {
            consumer.accept(value);
        }
    }

    public T get() {
        return value;
    }

    public T orElse(T other) {
        return value != null ? value : other;
    }

    @PowerNukkitOnly
    @Since("1.4.0.0-PN")
    public T orElseGet(Supplier other) {
        return value != null ? value : other.get();
    }

    @PowerNukkitOnly
    @Since("1.4.0.0-PN")
    public  T orElseThrow(Supplier exceptionSupplier) throws X {
        if (value != null) {
            return value;
        } else {
            throw exceptionSupplier.get();
        }
    }

    @Override
    public String toString() {
        return value == null ? "OptionalValue.empty" : "OptionalValue[" + value + "]";
    }
}