Computer scienceProgramming languagesJavaCode organizationGeneric programmingGenerics internals

Generics and Reflection

Theory

Getting the type of comparator

Report a typo

You need to implement method getComparatorType(Class) in ComparatorInspector class. The method should examine provided class and return Type object that corresponds to the type parameter that parameterizes Comparable interface the class implements. Consider the example:

class MyInt implements Comparable<Integer> {
    // Implementation omitted 
}

// Method to implement
Type type = ComparatorInspector.getComparatorType(MyInt.class);

System.out.println(type.getTypeName());
// prints: java.lang.Integer since MyInt implements Comparable with Integer parameter type

The method should:

  • Return type parameter for Comparable interface class implements
  • Return null if Comparable interface does not have type parameter
  • Should not produce compile-time warnings

Additional requirements:

  • Compile-time error should arise if class not implementing Comparable is provided as input value
  • No 'rawtype' warnings should remain or be suppressed
  • Method getComparatorType should be generic

You are free to correct method's type signature if needed.

Sample Input 1: 

ComparatorInspector class

Sample Output 1: 

Well done!
Write a program in Java 17
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/**
* Class to work with
*/
class ComparatorInspector {

/**
* Return Type variable that corresponds to the type parameterizing Comparator.
*
* @param clazz {@link Class} object, should be non null
* @return {@link Type} object or null if Comparable does not have type parameter
*/
public static <T> Type getComparatorType(Class clazz) {
// Add implementation
}

}
___

Create a free account to access the full topic