🔖 泛型示例

dunwu · dunwu · commit 23be711c60c8 · 2018-06-02T19:45:17.000+08:00
diff --git a/codes/advanced/src/main/java/io/github/dunwu/javase/util/TupleUtil.java b/codes/advanced/src/main/java/io/github/dunwu/javase/util/TupleUtil.java
@@ -0,0 +1,27 @@
+package io.github.dunwu.javase.util;
+
+import io.github.dunwu.javase.util.tuple.FiveTuple;
+import io.github.dunwu.javase.util.tuple.FourTuple;
+import io.github.dunwu.javase.util.tuple.ThreeTuple;
+import io.github.dunwu.javase.util.tuple.TwoTuple;
+
+/**
+ * 元祖工具类
+ */
+public class TupleUtil {
+    public static <A, B> TwoTuple<A, B> tuple(A a, B b) {
+        return new TwoTuple<A, B>(a, b);
+    }
+
+    public static <A, B, C> ThreeTuple<A, B, C> tuple(A a, B b, C c) {
+        return new ThreeTuple<A, B, C>(a, b, c);
+    }
+
+    public static <A, B, C, D> FourTuple<A, B, C, D> tuple(A a, B b, C c, D d) {
+        return new FourTuple<A, B, C, D>(a, b, c, d);
+    }
+
+    public static <A, B, C, D, E> FiveTuple<A, B, C, D, E> tuple(A a, B b, C c, D d, E e) {
+        return new FiveTuple<A, B, C, D, E>(a, b, c, d, e);
+    }
+}
diff --git a/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/FiveTuple.java b/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/FiveTuple.java
@@ -0,0 +1,16 @@
+//: net/mindview/util/FiveTuple.java
+package io.github.dunwu.javase.util.tuple;
+
+public class FiveTuple<A,B,C,D,E>
+extends FourTuple<A,B,C,D> {
+  public final E fifth;
+  public FiveTuple(A a, B b, C c, D d, E e) {
+    super(a, b, c, d);
+    fifth = e;
+  }
+  @Override
+  public String toString() {
+    return "(" + first + ", " + second + ", " +
+      third + ", " + fourth + ", " + fifth + ")";
+  }
+} ///:~
diff --git a/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/FourTuple.java b/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/FourTuple.java
@@ -0,0 +1,15 @@
+//: net/mindview/util/FourTuple.java
+package io.github.dunwu.javase.util.tuple;
+
+public class FourTuple<A,B,C,D> extends ThreeTuple<A,B,C> {
+  public final D fourth;
+  public FourTuple(A a, B b, C c, D d) {
+    super(a, b, c);
+    fourth = d;
+  }
+  @Override
+  public String toString() {
+    return "(" + first + ", " + second + ", " +
+      third + ", " + fourth + ")";
+  }
+} ///:~
diff --git a/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/ThreeTuple.java b/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/ThreeTuple.java
@@ -0,0 +1,14 @@
+//: net/mindview/util/ThreeTuple.java
+package io.github.dunwu.javase.util.tuple;
+
+public class ThreeTuple<A,B,C> extends TwoTuple<A,B> {
+  public final C third;
+  public ThreeTuple(A a, B b, C c) {
+    super(a, b);
+    third = c;
+  }
+  @Override
+  public String toString() {
+    return "(" + first + ", " + second + ", " + third +")";
+  }
+} ///:~
diff --git a/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/TwoTuple.java b/codes/advanced/src/main/java/io/github/dunwu/javase/util/tuple/TwoTuple.java
@@ -0,0 +1,16 @@
+package io.github.dunwu.javase.util.tuple;
+
+public class TwoTuple<A, B> {
+    public final A first;
+    public final B second;
+
+    public TwoTuple(A a, B b) {
+        first = a;
+        second = b;
+    }
+
+    @Override
+    public String toString() {
+        return "(" + first + ", " + second + ")";
+    }
+}
diff --git a/codes/advanced/src/test/java/io/github/dunwu/javase/util/TupleUtilTest.java b/codes/advanced/src/test/java/io/github/dunwu/javase/util/TupleUtilTest.java
@@ -0,0 +1,55 @@
+package io.github.dunwu.javase.util;
+
+import io.github.dunwu.javase.util.tuple.FiveTuple;
+import io.github.dunwu.javase.util.tuple.FourTuple;
+import io.github.dunwu.javase.util.tuple.ThreeTuple;
+import io.github.dunwu.javase.util.tuple.TwoTuple;
+import org.junit.Test;
+
+import java.util.ArrayList;
+
+/**
+ * @author Zhang Peng
+ */
+public class TupleUtilTest {
+    static TwoTuple<String, Integer> f() {
+        return TupleUtil.tuple("hi", 47);
+    }
+
+    static ThreeTuple<Amphibian, String, Integer> g() {
+        return TupleUtil.tuple(new Amphibian(), "hi", 47);
+    }
+
+    static FourTuple<Vehicle, Amphibian, String, Integer> h() {
+        return TupleUtil.tuple(new Vehicle(), new Amphibian(), "hi", 47);
+    }
+
+    static FiveTuple<Vehicle, Amphibian, String, Integer, Double> k() {
+        return TupleUtil.tuple(new Vehicle(), new Amphibian(), "hi", 47, 11.1);
+    }
+
+    static class TupleList<A, B, C, D> extends ArrayList<FourTuple<A, B, C, D>> {}
+
+    static class Amphibian {}
+
+    static class Vehicle {}
+
+    @Test
+    public void test() {
+        TwoTuple<String, Integer> ttsi = f();
+        System.out.println(ttsi);
+        // ttsi.first = "there"; // Compile error: final
+        System.out.println(g());
+        System.out.println(h());
+        System.out.println(k());
+    }
+
+    @Test
+    public void testList() {
+        TupleList<Vehicle, Amphibian, String, Integer> tl = new TupleList<>();
+        tl.add(h());
+        tl.add(h());
+        for (FourTuple<Vehicle, Amphibian, String, Integer> i : tl)
+            System.out.println(i);
+    }
+}
