How do I return 0 for equality?

Gabriel,

You will want to use the this keyword as it is a reference variable that refers to the current object. It will allow you to test for equality between this object and the one being passed into the compareTo(Object obj) method after you complete the casting of a BlogPost. You should use the equals() method to do so.

Some hints for Task 2/3

 @Override
  public int compareTo(Object obj) {
   // declare a BlogPost named post and assign the cast of obj to it.
   // test if **this** equals(post) and return 0 if it does

    // said to keep return 1 for now.
    return 1;
  }

Hints for 3/3: Once you have the code completed for 2/3, you want to only change the return 1 statement here to return a comparison of this creation date with the creation date of post. Use the compareTo() method to do so. Remember, the compareTo() method you are writing is your Overridden version of it; however, calling compareTo() inside your implementation would be calling the Object's compareTo() method. In this case, that would be a Date object that implements Comparable and has it's own compareTo() method.

@Override
  public int compareTo(Object obj) {
   // declare a BlogPost named post and assign the cast of obj to it.
   // test if **this** equals(post) and 
   // return 0 if it does


   //return **this** date using compareTo(post's date);

  }

Regards,

Chris

OK so lets tackle the second one first. You pass java object that is actually a BlogPost in the method so you need to make it into a BlogPost to be able to compare it. And you compare it to the original object by using the equals method. I'm going to show you an example of how Craig uses this with Treets, which is the same concept

public int compareTo(Object obj){
//So we need to make the object into a Treet so we can compare it:
Treet treet = (Treet) obj; //This line of code stores the obj information into a Treet
//We can do that since Treet is a child of Object

//next we need to check if it equals the original object which we can do with the equals() method
//the method returns a boolean(true or false) so we can pass it in an if statement
if(equals(treet)){
return 0; //so this means if the equals method returns true then it will return 0
}
return 1;//we return a 1 as a default just in case the condition didn't work out
}

With the third one, we need to compare the creationDate of the treet so instead of the default 1 being returned, we can return an actual comparison based on the earlier post.

public int compareTo(Object obj){
Treet treet = (Treet) obj;
if(equals(treet)){
return 0;
}
//So we need to call the compareTo() method to compare the dates
//but this returns an int so we need to store it to see the result
int compare = mCreationDate.compareTo(treet.getCreationDate); 
//so whatever gets returned in the compareTo method will be the comparison we need
//so lets return it so we know which one came first based on the response
return compare;
}

I went back and went through the challenges to refresh myself on it. I'll post some more detailed instructions. If you need a code example let me know and i'll post one too.

Second Challenge: -First, you need to cast the object you passed into your compareTo method into a BlogPost. To do that just create a new BlogPost and declared as the casted object. -Second, you need to create an if statement that checks if the objects equal each other, using the new BlogPost you created. And return 0 if that is the case. -Third, the return 1 statement needs to be after the if statement. To return 1 if the condition isn't true.

Third Challenge: -First, you need to get rid of your default return statement that returns 1. -Second, create an int to store the comparison of your mCreationDate of the current blog post and the post you created by casting the object. -Third, return the int you created to check equality.

Feel free to ask me any other questions. Hope this helps :).