Compare objects in LinkedList.contains()

Question

I want to be able to have LinkedList.contains() return true for a custom comparator.

Suppose that I have 1 LinkedList and 2 objects

LinkedList

        

Answer 1

The documentation for the contains method is as follows:

Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).

Therefore, you need to override the MyObject's equals(Object o) method.

So for your example:

public class MyObject {
  String myVal;

  public boolean equals(Object o ) {
    return ((MyObject)o).myVal.equals(myVal);
  }
}

You do not need to implement anything with the Comparable interface.