避免未经检查的警告在以下

Question

我已经做了一些奇特的包装，以避免过去未经检查的警告，但90分钟后深入http://www.angelikalanger.com/GenericsFAQ/JavaGenericsFAQ.html，我不能写下面的findMatch方法，并使其工作没有@SuppressWarnings（“未登记“）。参数化的类在编译时不知道。

public interface Matchable<T> 
{ 
    public boolean matches(T toMatch); 
}  

public class PlaceForMatching 
{ 
    public static Object findMatch(Object toMatch, Object[] toSearch) 
    { 
    if(!(toMatch instanceof Matchable)) return null; 

    Matchable matchObj = (Matchable)toMatch; 
    Class<?> matchClass = matchObj.getClass(); 

    for(Object obj : toSearch) 
    { 
     /** 
      * Check here verifies that the search list object we're about 
      * to check is the same class as the toMatch object. 
      * This means Matchable will work without a ClassCastException. 
     **/ 

     if(matchClass.isInstance(obj) && matchObj.matches(obj)) 
      return obj; 
    } 
    //Didn't find it 
    return null; 
    } 
} 

注意代码的工作，因为在任何情况下可匹配由T实现

Apple implements Matchable<Apple> 
Orange implements Matchable<Orange> 

编辑：添加一些测试代码

public static void main(String[] args) 
{ 
    Object[] randomList = createAppleArray(); 
    Object apple = new Apple("Red"); 

    Object match = findMatch(apple, randomList); 
} 

private static Object[] createAppleArray() 
{ 
    return new Object[] { new Apple("Pink"), new Apple("Red"), new Apple("Green") }; 
} 


public class Apple implements Matchable<Apple> 
{ 
    String color; 
    public Apple(String color) 
    { 
     this.color = color; 
    } 

    public boolean matches(Apple apple) 
    { 
     return color.equals(apple.color); 
    } 
} 

Answer 1

public static <T extends Matchable<T>> T findMatch(T toMatch, T[] toSearch) { 
    if (toMatch == null) 
    return null; 

    Matchable<T> matchObj = toMatch; 
    Class<?> matchClass = matchObj.getClass(); 

    for (T obj : toSearch) { 
    if (matchClass.isInstance(obj) && matchObj.matches(obj)) 
     return obj; 
    } 

    return null; 
}