Overriding “equals” method: how to figure out the type of the parameter?

Question

I\'m trying to override equals method for a parameterized class.

@Override
public boolean equals(Object obj) {
    if (this == obj)
        return t         


        

Answer 1

I agree with the comments above, why does the class E need to be equal? and how do you want to treat subclasses of E?

Anyway, given that here is a code sample that may help you:

public class Example {

  T t;

  public Example(T t) {
    this.t = t;
  }

  public static void main(String[] args) {
    final String s = "string";
    final Integer i = 1;
    final Number n = 1;

    final Example exampleString = new Example(s);
    final Example exampleInteger = new Example(i);
    final Example exampleNumber = new Example(n);

    System.out.println("exampleString subclass "  + exampleString.t.getClass());
    System.out.println("exmapleIntger subclass " + exampleInteger.t.getClass());
    System.out.println("exmapleNumber subclass " + exampleNumber.t.getClass());
    System.out.println("Integer equals Number = " + 
        exampleInteger.t.equals(exampleNumber.t));
  }
}

You can call t.getClass() to get class information about the type of T (assuming it is not null, of course.)

I hope this helps.