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• 1.0.2
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• Either3.java

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com.shapesecurity.shift.es2017.utils.Either3 Maven / Gradle / Ivy

package com.shapesecurity.shift.es2017.utils;

import com.shapesecurity.functional.F;
import com.shapesecurity.functional.data.Maybe;

import javax.annotation.CheckReturnValue;
import javax.annotation.Nonnull;
import java.util.Objects;

// TODO port this to shape-functional-java
@CheckReturnValue
public final class Either3 {
	private final Object data;

	private enum Tag {
		LEFT, MIDDLE, RIGHT
	}

	private final Tag tag;

	private Either3(Object data, Tag tag) {
		super();
		this.data = data;
		this.tag = tag;
	}

	@Nonnull
	public static  Either3 left(@Nonnull A a) {
		return new Either3<>(a, Tag.LEFT);
	}

	@Nonnull
	public static  Either3 middle(@Nonnull B b) {
		return new Either3<>(b, Tag.MIDDLE);
	}

	@Nonnull
	public static  Either3 right(@Nonnull C c) {
		return new Either3<>(c, Tag.RIGHT);
	}

	public final boolean isLeft() {
		return this.tag == Tag.LEFT;
	}

	public final boolean isMiddle() {
		return this.tag == Tag.MIDDLE;
	}

	public final boolean isRight() {
		return this.tag == Tag.RIGHT;
	}

	@SuppressWarnings("unchecked")
	public  X either(F f1, F f2, F f3) {
		if (this.tag == Tag.LEFT) {
			return f1.apply((A) this.data);
		} else if (this.tag == Tag.MIDDLE) {
			return f2.apply((B) this.data);
		} else {
			return f3.apply((C) this.data);
		}
	}

	@Nonnull
	public  Either3 map(F f1, F f2,  F f3) {
		return this.either(a -> Either3.left(f1.apply(a)), b -> Either3.middle(f2.apply(b)), c -> Either3.right(f3.apply(c)));
	}

	@Nonnull
	public  Either3 mapLeft(@Nonnull F f) {
		return this.map(f, b -> b, c -> c);
	}

	@Nonnull
	public  Either3 mapMiddle(@Nonnull F f) {
		return this.map(a -> a, f, c -> c);
	}

	@Nonnull
	public  Either3 mapRight(@Nonnull F f) {
		return this.map(a -> a, b -> b, f);
	}

	@SuppressWarnings("unchecked")
	@Nonnull
	public Maybe left() {
		return this.tag == Tag.LEFT ? Maybe.of((A) this.data) : Maybe.empty();
	}

	@SuppressWarnings("unchecked")
	@Nonnull
	public Maybe middle() {
		return this.tag == Tag.MIDDLE ? Maybe.of((B) this.data) : Maybe.empty();
	}

	@SuppressWarnings("unchecked")
	@Nonnull
	public Maybe right() {
		return this.tag == Tag.RIGHT ? Maybe.of((C) this.data) : Maybe.empty();
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;
		Either3 either3 = (Either3) o;
		return tag == either3.tag && Objects.equals(data, either3.data);
	}

	@Override
	public int hashCode() {
		return Objects.hash(data, tag);
	}
}