java中的tuple实现

java中没有类似c#、scala中的tuple元组类，只能自己动手，丰衣足食了，见下面的代码：

Tuple 抽象类

import java.util.Optional;

/**
 * Tuple元组类
 *
 * @since: 12/4/15.
 * @author: http://yjmyzz.cnblogs.com/
 */
public abstract class Tuple {

    public abstract <A> Optional<A> _1();

    public abstract <B> Optional<B> _2();

    public abstract <C> Optional<C> _3();

    public abstract <D> Optional<D> _4();

    public abstract <E> Optional<E> _5();

    public static <A, B> Tuple of(A a, B b) {
        return new Tuple2(a, b);
    }

    public static <A, B, C> Tuple of(A a, B b, C c) {
        return new Tuple3(a, b, c);
    }

    public static <A, B, C, D> Tuple of(A a, B b, C c, D d) {
        return new Tuple4(a, b, c, d);
    }

    public static <A, B, C, D, E> Tuple of(A a, B b, C c, D d, E e) {
        return new Tuple5(a, b, c, d, e);
    }


    public static void main(String[] args) {
        Tuple t2 = Tuple.of(1, "one");
        System.out.println(t2);
        System.out.println(t2._1().get() + "," + t2._2().get());


        Tuple t3 = Tuple.of(1, "one", "一");
        System.out.println(t3);
        System.out.println(t3._1().get() + "," + t3._2().get() + "," + t3._3().get());


        Tuple t4 = Tuple.of(1, "one", "一", "壹");
        System.out.println(t4);
        System.out.println(t4._1().get() + "," + t4._2().get() + "," + t4._3().get() + "," + t4._4().get());

        Tuple t5 = Tuple.of(1, "one", "一", "壹", "yi");
        System.out.println(t5);
        System.out.println(t5._1().get() + "," + t5._2().get() + "," + t5._3().get() + "," + t5._4().get() + "," + t5._5().get());
    }

}

Tuple2

import java.util.Optional;

public class Tuple2<A, B> extends Tuple {
    private A a;
    private B b;

    Tuple2(A a, B b) {
        this.a = a;
        this.b = b;
    }

    @Override
    public Optional<A> _1() {
        return Optional.of(a);
    }

    @Override
    public Optional<B> _2() {
        return Optional.of(b);
    }

    @Override
    public <C> Optional<C> _3() {
        return Optional.empty();
    }

    @Override
    public <D> Optional<D> _4() {
        return Optional.empty();
    }

    @Override
    public <E> Optional<E> _5() {
        return Optional.empty();
    }

    @Override
    public String toString() {
        return "Tuple2{" +
                "a=" + a +
                ", b=" + b +
                '}';
    }
}

Tuple3

import java.util.Optional;

public class Tuple3<A, B, C> extends Tuple {
    private A a;
    private B b;
    private C c;

    Tuple3(A e, B t, C k) {
        this.a = e;
        this.b = t;
        this.c = k;
    }

    public Optional<A> _1() {
        return Optional.of(a);
    }

    public Optional<B> _2() {
        return Optional.of(b);
    }

    public Optional<C> _3() {
        return Optional.of(c);
    }

    @Override
    public <D> Optional<D> _4() {
        return Optional.empty();
    }

    @Override
    public <E> Optional<E> _5() {
        return Optional.empty();
    }

    @Override
    public String toString() {
        return "Tuple3{" +
                "a=" + a +
                ", b=" + b +
                ", c=" + c +
                '}';
    }
}

Tuple4

import java.util.Optional;

public class Tuple4<A, B, C, D> extends Tuple {
    private A a;
    private B b;
    private C c;
    private D d;

    Tuple4(A a, B b, C c, D d) {
        this.a = a;
        this.b = b;
        this.c = c;
        this.d = d;
    }

    public Optional<A> _1() {
        return Optional.of(a);
    }

    public Optional<B> _2() {
        return Optional.of(b);
    }

    public Optional<C> _3() {
        return Optional.of(c);
    }

    public Optional<D> _4() {
        return Optional.of(d);
    }

    @Override
    public <E> Optional<E> _5() {
        return Optional.empty();
    }

    @Override
    public String toString() {
        return "Tuple4{" +
                "a=" + a +
                ", b=" + b +
                ", c=" + c +
                ", d=" + d +
                '}';
    }
}

Tuple5

import java.util.Optional;

public class Tuple5<A, B, C, D, E> extends Tuple {
    private A a;
    private B b;
    private C c;
    private D d;
    private E e;

    Tuple5(A a, B b, C c, D d, E e) {
        this.a = a;
        this.b = b;
        this.c = c;
        this.d = d;
        this.e = e;
    }

    public Optional<A> _1() {
        return Optional.of(a);
    }

    public Optional<B> _2() {
        return Optional.of(b);
    }

    public Optional<C> _3() {
        return Optional.of(c);
    }

    public Optional<D> _4() {
        return Optional.of(d);
    }

    public Optional<E> _5() {
        return Optional.of(e);
    }

    @Override
    public String toString() {
        return "Tuple5{" +
                "a=" + a +
                ", b=" + b +
                ", c=" + c +
                ", d=" + d +
                ", e=" + e +
                '}';
    }
}

5个元素一般情况下够用了，如果觉得不够，按这个套路自行扩展吧。