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Java Java Data Structures - Retired Organizing Data Comparable

Posted by melissakeith
melissakeith
3,766 Points

Keep getting error: unreachable statement in compareTo task

I've tried dateCmp and got the same error

com/example/BlogPost.java 
package com.example;

import java.util.Date;

public class BlogPost implements Comparable {
  private String mAuthor;
  private String mTitle;
  private String mBody;
  private String mCategory;
  private Date mCreationDate;

  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
  }

  public int compareTo(Object obj) {
    BlogPost other = (BlogPost) obj;
    return 1;
    int compareCreationDate = mCreationDate.compareTo(other.mCreationDate);
    if (compareCreationDate == 0) {
      return mCreationDate.compareTo(other.mCreationDate);
    }
    return compareCreationDate;
  }

  public String[] getWords() {
    return mBody.split("\\s+");
  }

  public String getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

  public String getBody() {
    return mBody;
  }

  public String getCategory() {
    return mCategory;
  }

  public Date getCreationDate() {
    return mCreationDate;
  }
}

4 Answers

melissakeith
melissakeith
3,766 Points

Nevermind, this is what worked. 

public int compareTo (Object obj) {
    BlogPost other = (BlogPost) obj;
     int compareCreationDate = mCreationDate.compareTo(other.mCreationDate);
    if (equals(other)) {
    return 0;
    } else {
      return mCreationDate.compareTo(other.mCreationDate);
    }
  }
Deividas Strioga
Deividas Strioga
12,851 Points
Deividas Strioga
Deividas Strioga
12,851 Points

Hey Melissa, It seems i made a mistake, instead of other i wrote post object. Sorry, it mislead you :) For task 2 this code should have been enough:

public int compareTo (Object obj) {
    BlogPost other = (BlogPost) obj;
    if (equals(other)) {
    return 0;
    } 
return 1;
  }
Deividas Strioga
Deividas Strioga
12,851 Points
Deividas Strioga
Deividas Strioga
12,851 Points

Hello Melissa, in the compareTo method you have 2 return statements. After the first one, return 1, the method breaks and the following code simply does not have a chance to run. I do not think that this return is necessary for your code to run, try removing this line. Cheers!

melissakeith
melissakeith
3,766 Points 
package com.example;

import java.util.Date;

public class BlogPost implements Comparable{
  private String mAuthor;
  private String mTitle;
  private String mBody;
  private String mCategory;
  private Date mCreationDate;

  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
  }

  public int compareTo(Object obj) {
    BlogPost other = (BlogPost) obj;
    int compareCreationDate = mCreationDate.compareTo(other.mCreationDate);
    if (compareCreationDate == 0) {
      return mCreationDate.compareTo(other.mCreationDate);
    }
  }


  public String[] getWords() {
    return mBody.split("\\s+");
  }

  public String getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

  public String getBody() {
    return mBody;
  }

  public String getCategory() {
    return mCategory;
  }

  public Date getCreationDate() {
    return mCreationDate;
  }
}

What I had to add was the compareTo method. The task is to "cast the object past to the compareTo method to a com.example.BlogPost. Check for quality first, if they are equal return 0. Leave the default return of one in place for this statement."

This is the error I keep getting.

./com/example/BlogPost.java:26: error: missing return statement
  }
  ^
1 error
Deividas Strioga
Deividas Strioga
12,851 Points
Deividas Strioga
Deividas Strioga
12,851 Points

First part of the task - "cast the object past to the compareTo method to a com.example.BlogPost" - is done. And the second part has to be done the same way as in Craig's last video. "Check for quality first, if they are equal return 0". So you have to compare the passed in object to a casted one, new object, post in your case, in the if statement:

if (equals(post)) {
    return 0;
    }

If they are equal, the method will return 0 and will not continue. If they are not equal, the method continues. For now we just have to return 1 after the if statement.

melissakeith
melissakeith
3,766 Points

Thank you, I tried that but I'm still getting an error.

public int compareTo (Object obj) {
    BlogPost other = (BlogPost) obj;
    return 1;
     int compareCreationDate = mCreationDate.compareTo(other.mCreationDate);
    if (equals(post)) {
    return 0;
    } else {
      return mCreationDate.compareTo(other.mCreationDate);
    }
  }

and the error message is 

./com/example/BlogPost.java:24: error: cannot find symbol
    if (equals(post)) {
               ^
  symbol:   variable post
  location: class BlogPost
1 error

I've tried every other option I could think of; Post, BlogPost, Object, obj, etc. nothing worked?

melissakeith
melissakeith
3,766 Points
melissakeith
melissakeith
3,766 Points

I also tried removing the 

return 1;

but still got the same error message