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Start your free trialNeil Gordon
8,823 PointsCompare to date question ??
public int compareTo(Object obj) { if(equals(obj)) { int compareDate = mCreationDate.compareTo(Object.mCreationDate); return compareDate; return 0;
}
return 1;
}
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) {
if(equals(obj)) {
int compareDate = mCreationDate.compareTo(Object.mCreationDate);
return compareDate;
return 0;
}
return 1;
}
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
Allan Clark
10,810 PointsFirst you will need to cast the parameter into a BlogPost Object. With the variable stored as an Object, it does not have access to the methods and variables you will need to do the comparison.
BlogPost bp = (BlogPost) obj;
for step 2 you only need to return 0 if they are equal so it would look something like this:
if(equals(bp)) {
return 0;
}
Neil Gordon
8,823 PointsThank you , I updated the typecasting here is my new code
public int compareTo(Object obj){
BlogPost bp = (BlogPost) obj;
if (equals(bp)) {
return 0;
}
return 1;
int compareDate = mCreationDate.compareTo(bp.mCreationDate);
return compareDate;
}```
since i type casted bp inserted it into the *compareDate* method if this is wrong then I will have to take some more practice. *replacing Object with bp*
below is my new error
/com/example/BlogPost.java:28: error: unreachable statement
int compareDate = mCreationDate.compareTo(bp.mCreationDate);
^
1 error
i am not sure why I cannot reach this statement. I see the arrow pointing to compareDate.
Neil Gordon
8,823 PointsExpected -1 but received 1, when comparing Sun Jul 20 20:18:00 UTC 1969 to Mon Mar 09 16:00:00 UTC 2015
Allan Clark
10,810 PointsJava returns and exits the method whenever it hits the first return keyword.
if (equals(bp)) {
return 0;
}
return 1;
int compareDate = mCreationDate.compareTo(bp.mCreationDate);
return compareDate;
So written like this, the method returns 0 if they are equal, if they are not equal it skips the if statement and hits the return 1; line. So it is impossible for the JVM control to reach what you have below it. You can also just directly return the comparison, to skip having to create a variable and return the variable. Try replacing the return 1 line with this:
// remember mCreationDate is a private variable so for bp you have to use the accessor method
return mCreationDate.compareTo(bp.getCreationDate());
Neil Gordon
8,823 Points@craigsdennis can you help when you have a moment not quite sure how to push forward with the above errors