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。