I think that i return a valid value..

Question

please help me with this example....

com/example/BlogPost.java

package com.example;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;


public class BlogPost implements Comparable<BlogPost>, Serializable {
  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(BlogPost other) {
    if (equals(other)) {
      return 0;
    }
    return mCreationDate.compareTo(other.mCreationDate);
  }

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

  public List<String> getExternalLinks() {
    List<String> links = new ArrayList<String>();
    for (String word : getWords()) {
      if (word.startsWith("http")) {
        links.add(word);
      }
    }
    return links;
  }

  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;
  }
}

com/example/Blog.java

package com.example;

import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.Map;
import java.util.HashMap;

public class Blog {
  List<BlogPost> mPosts;



  public Blog(List<BlogPost> posts) {
    mPosts = posts;
  }

  public Map getCategoryCounts(){
   Map<String, Integer> categoryCount = new HashMap<String, Integer>();
    for(BlogPost post: mPosts){
                Integer count = categoryCount.get(post.getCategory());
                    if (count == null){
                        count = 0;
                    }
                    count++;
                    categoryCount.put(post.getCategory(), count);
                }

    return categoryCount;
  }


  public List<BlogPost> getPosts() {
    return mPosts;
  }

  public Set<String> getAllAuthors() {
    Set<String> authors = new TreeSet<>();
    for (BlogPost post: mPosts) {
      authors.add(post.getAuthor());
    }
    return authors;
  }


}

Answer 1 · 2017-04-05T22:50:29Z

April 5, 2017 10:50pm

The problem is not the object you are returning, but the return type you have specified for the method. You have specified the return type as Map, while in reality you are returning an object of type Map<String, Integer>. Those values between the less than and greater than sign are important when specifying the return type, just like they are when you are defining the Map object itself.

If you simply add them to the return type like this:

public Map<String, Integer> getCategoryCounts(){
    Map<String, Integer> categoryCount = new HashMap<String, Integer>();
    for(BlogPost post: mPosts){
        Integer count = categoryCount.get(post.getCategory());
        if (count == null){
            count = 0;
        }
        count++;
        categoryCount.put(post.getCategory(), count);
    }
    return categoryCount;
  }

Then your code will work.

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Cristian Escamilla

Cristian Escamilla

I think that i return a valid value..

1 Answer

andren

andren

Cristian Escamilla

Cristian Escamilla