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| import java.util.function.Function;
public class Main6 {
public static void main(String[] args) { boolean debug = true;
if (debug) { TestM.myrun(); }
if (debug == false) {
MyBox<String> box = new MyBox<>("hello");
Integer length = box.<Integer>map(str -> str.length()).get(); System.out.println("长度是:" + length);
ResponseEntity<Void> resp = box.<ResponseEntity<Void>>map(str -> { System.out.println("值是:" + str);
return ResponseEntity.noContent(); }).orElse(ResponseEntity.<Void>notFound());
System.out.println(resp); } }
}
class MyBox<T> { private final T value;
public MyBox(T value) { this.value = value; }
public static <T> MyBox<T> empty() { return new MyBox<>(null); }
public static <T> MyBox<T> of(T value) { return new MyBox<>(value); }
public boolean isPresent() { return value != null; }
public T get() { return value; }
public <R> MyBox<R> map(Function<? super T, ? extends R> func) { if (value != null) { return new MyBox<>(func.apply(value)); } else { return new MyBox<>(null); } }
public T orElse(T defaultValue) { return value != null ? value : defaultValue; }
public static void main(String[] args) { MyBox<String> box = MyBox.of("hello");
ResponseEntity<Void> result = box.<ResponseEntity<Void>>map(str -> { System.out.println("处理内容:" + str); return ResponseEntity.noContent(); }).orElse(ResponseEntity.<Void>notFound());
System.out.println(result);
MyBox<String> emptyBox = MyBox.empty(); ResponseEntity<Void> result2 = emptyBox.<ResponseEntity<Void>>map(str -> ResponseEntity.noContent()).orElse(ResponseEntity.<Void>notFound());
System.out.println(result2); } }
class ResponseEntity<T> { private final int status;
private ResponseEntity(int status) { this.status = status; }
public static <T> ResponseEntity<T> noContent() { return new ResponseEntity<>(204); }
public static <T> ResponseEntity<T> notFound() { return new ResponseEntity<>(404); }
@Override public String toString() { return "ResponseEntity: " + status; } }
class TestM { public static void myrun() {
Test4<Test3<String>> test4 = new Test4(new Test3<>("hi,Test3"));
System.out.println(test4.<Test3<String>>print2_myfun((in) -> { return in; }));
Test4<Test4<String>> test4_2 = new Test4(new Test4<>("hi,Test4"));
System.out.println(test4_2.<Test4<String>>print2_myfun((in) -> { return in; }).orElse("hi,I null."));
Test4<String> test4_3 = new Test4("hi,Test4_3");
String out4_3 = test4_3.map((in)->{return in;}).orElse("hi,I null in Test4_3."); System.out.println(out4_3);
Test4<String> test4_5 = new Test4("hi,Test4_5");
String out4_5 = test4_5.map((in)->{return in;}).<Object>orElse("hi,I null in Test4_5."); System.out.println(out4_5);
}
}
class Test2<T2> { private T2 data;
public T2 getData() { return data; }
public void setData(T2 data) { this.data = data; }
public static <T2_1> void print2_1(Test3<? extends T2_1> data) { System.out.println(data.getClass().getName() + " : " + data);
}
public static <T2_2> void print2_2(Test3<Test3<? extends T2_2>> data) { System.out.println(data.getClass().getName() + " : " + data);
}
public static <T2_3> void print2_3(Test3<? extends Test3> data) { System.out.println(data.getClass().getName() + " : " + data);
}
public static <T2_4, T2_4_2> void print2_4(Test3<? extends T2_4> data) { System.out.println(data.getClass().getName() + " : " + data);
}
}
class Test3<T3> { public Test3(T3 data) { this.data = data; }
private T3 data;
public T3 getData() { return data; }
public void setData(T3 data) { this.data = data; }
@Override public String toString() { return "Test3{" + "data=" + data + '}'; } }
class Test4<T4_in> { public Test4(T4_in indata) { data = indata; }
public T4_in data;
public <T4_out> T4_out print2_myfun(MyFun<T4_in, T4_out> myFun) {
System.out.println("data type=" + data.getClass().getName());
return myFun.mydo(data);
}
public T4_in orElse(T4_in defaultValue) { return data != null ? data : defaultValue; }
public <R> Test4<R> map(MyFun<? super T4_in, ? extends R> func) { if (data != null) { return new Test4<>(func.mydo(data)); } else { return new Test4<>(null); } }
}
interface MyFun<TMF_in, TMF_out> { TMF_out mydo(TMF_in in); }
|