SectionArticle.java

@AutoValue public static abstract class SectionArticle {
  @Nullable public abstract Article article();

  @Nullable public abstract String category();

  public static SectionArticle createCategory(Article article) {
    return new AutoValue_SectionArticlesActivity_SectionArticle(null, article.category());
  }

  public static SectionArticle createArticle(Article article) {
    return new AutoValue_SectionArticlesActivity_SectionArticle(article, null);
  }

  public boolean isCategory() {
    return article() == null;
  }

  public boolean isArticle() {
    return category() == null;
  }

  public int compare(SectionArticle that) {
    if (this.isCategory() && that.isCategory()) {
      return this.category().compareToIgnoreCase(that.category());
    } else if (this.isCategory() && that.isArticle()) {
      if (this.category().equalsIgnoreCase(that.article().category())) {
        return -1;
      } else {
        return this.category().compareToIgnoreCase(that.article().category());
      }
    } else if (this.isArticle() && that.isCategory()) {
      if (this.article().category().equalsIgnoreCase(that.category())) {
        return 1;
      } else {
        return this.article().category().compareToIgnoreCase(that.category());
      }
    } else {
      if (this.article().category().equalsIgnoreCase(that.article().category())) {
        return this.article().compare(that.article());
      } else {
        return this.article().category().compareToIgnoreCase(that.article().category());
      }
    }
  }

  public boolean areContentsTheSame(SectionArticle that) {
    return this.equals(that);
  }

  public boolean areItemsTheSame(SectionArticle that) {
    if (this.isCategory() && that.isCategory()) {
      return this.category().equalsIgnoreCase(that.category());
    } else if (this.isArticle() && that.isArticle()) {
      return this.article().id() == that.article().id();
    }
    return false;
  }
}