Java 继承和理解接口类

Question

我正在处理我已经设置的一个简短的 java 任务。

问题如下：

设计和编写类来模拟库中不同类型的出版物。仔细考虑不同类型的出版物，例如书籍和杂志。将所有出版物类型共有的所有属性和方法放在一个超类中，然后适当地扩展这个超类以创建一组子类。

确保在类中包含适当的构造函数、getter、setter 和自定义方法。在适当的情况下使用方法重载和覆盖。

在您的设计和类代码中最大限度地利用继承。

在您的设计和编码中实现以下接口类：

+ getPublisher() : String
+ getPublicationTitle() : String
+ getPrice : float
+ setPublication(publisherIn: String, titleIn:String, priceIn:float) : void

所以我已经尽我所能回答了，请任何人阅读它并检查我是否走在正确的轨道上并理解我要做什么，看起来很简单是正确的吗？ 哦，javadocs 还没有完成 [=

public interface PublicationInterface
{
    /**
     * Returns the book publisher name (as a String) 
     */
    public String getPublisher();

    /**
     * Returns the book publication title (as a String)
     */
    public String getPublicationTitle();

    /**
     * Returns the book price (as a float)
     */
    public float getPrice();

    /**
     * Sets the book publication details.
     * 
     * @param publisherIn   The Book Publisher (as a String)
     * @param titleIn       The Book Title (as a String)
     * @param priceIn       The Book Price (as a float)
     */
    public void setPublication(String publisherIn, String publicationTitleIn, float priceIn);
}

abstract public class Publications implements PublicationInterface
{
   // Attributes
  protected String publisher;
  protected String publicationTitle;
  protected float price;

        public Publications(String publisherIn, String publicationTitleIn, float priceIn)
            {
                publisher = publisherIn;
                publicationTitle = publicationTitleIn;
                price = priceIn;
            }

        public String getPublisher()
            {
                return (publisher);
            }

        public String getPublicationTitle()
            {
                return (publicationTitle);
            }

        public float getPrice()
            {
                return (price);
            }

        public void setPublication(String publisherIn, String publicationTitleIn, float priceIn)
            {
                publisher = publisherIn;
                publicationTitle = publicationTitleIn;
                price = priceIn;
           }

}

public class Magazine extends Publications
{
    String editor;
    String date;

    public Magazine(String publisherIn , String publicationTitleIn, float priceIn, String editorIn, String dateIn)
        {
            super (publisherIn , publicationTitleIn, priceIn);

            editor = editorIn;
            date = dateIn;
        }

    public void setPublication(String publisherIn, String publicationTitleIn, float priceIn)
        {
            publisherIn = publisher;
            publicationTitleIn = publicationTitle;
            priceIn = price;
        }

    public String getEditor()
        {
            System.out.println("The editor of this magazine is " + editor);
            return (editor);
        }

    public String getDate()
        {
            System.out.println("The publication date of this magazine is " + date);
            return (date);
        }

    public String getPublisher()
        {
            System.out.println("The publisher of this magazine is " + publisher);
            return (publisher);
        }

    public String getPublicationTitle()
        {
            System.out.println("The publication title of this magazine is " + publicationTitle);
            return (publicationTitle);
        }

    public float getPrice()
        {
            System.out.println("The price of this magazine is £" + price);
            return (price);
        }

}

public class ReferenceMaterial extends Publications
{

    String genre;
    String subject;

    public ReferenceMaterial(String publisherIn , String publicationTitleIn, float priceIn,     String genreIn, String subjectIn)
        {
            super (publisherIn , publicationTitleIn, priceIn);            

            genre = genreIn;
            subject = subjectIn;
        }

    public String getGenre()
        {
            System.out.println("The genre of this material is " + genre);
            return (genre);
        }

    public String getSubject()
        {
            System.out.println("The subject of this material is " + subject);
            return (subject);
        }

    public String getPublisher()
        {
            System.out.println("The publisher of this material is " + publisher);
            return (publisher);
        }

    public String getPublicationTitle()
        {
            System.out.println("The publication title of this material is " + publicationTitle);
            return (publicationTitle);
        }

    public float getPrice()
        {
            System.out.println("The price of this material is £" + price);
            return (price);
        }
}


public class Book extends Publications
{
    int pageNumber;
    String author;

    public Book(String publisherIn , String publicationTitleIn, float priceIn, int pageNumberIn,     String authorIn)
        {
            super (publisherIn , publicationTitleIn, priceIn);

            pageNumber = pageNumberIn;
            author = authorIn;

        }

    public int getPageNumber()
        {
            System.out.println("The number of pages in this book are " + pageNumber);
            return (pageNumber);
        }

    public String getAuthor()
        {
            System.out.println("The author of this book is " + author);
            return (author);
        }

    public String getPublisher()
        {
            System.out.println("The publisher of this book is " + publisher);
            return (publisher);
        }

    public String getPublicationTitle()
        {
            System.out.println("The publication title of this book is " + publicationTitle);
            return (publicationTitle);
        }

    public float getPrice()
        {
            System.out.println("The price of this book is £" + price);
            return (price);
        }

}

public class TestLibrary
{

    public static void main()
      {     
        Magazine magazine1 = new Magazine ("SanYonic Publishing", "Ayup Magazine", 99, "Yeshumenku Suni", "12/09/2011");

        System.out.println();
        magazine1.getEditor();
        magazine1.getDate();
        magazine1.getPublisher();
        magazine1.getPublicationTitle();
        magazine1.getPrice();
        System.out.println();

        ReferenceMaterial referenceMaterial1 = new ReferenceMaterial ("Dorling kindesy", "killer Sharks In The Solent", 200, "Nature", "Sharks");

        referenceMaterial1.getGenre();
        referenceMaterial1.getSubject();
        referenceMaterial1.getPublisher();
        referenceMaterial1.getPublicationTitle();
        referenceMaterial1.getPrice();
        System.out.println();

        Book Book1 = new Book ("Hodder & Soughton", "One Day", 75, 1105, "David Nicholls");

        Book1.getPageNumber();
        Book1.getAuthor();
        Book1.getPublisher();
        Book1.getPublicationTitle();
        Book1.getPrice();
        System.out.println();        
      }

}

Answer 1

这看起来不错，只是您根本不需要该界面。作业里没看到提到，子类化肯定没必要。

接口用于由一组不相关的类实现的通用方法（特别是不属于类层次结构的一部分）。

由于您的类都来自父 Publications 类，因此在这种情况下不需要像 PublicationsInterface 这样的东西。超类很好地填补了这个角色。

Publication p = new Book();
p.setPublisher("Acme Books");

Answer 2

您的设计并非不合理，尽管您的命名约定有点多余（您不需要使用Interface 后缀命名接口）。此外，请坚持使用单数名词作为类名，而不是从 Publications 切换到 Book。

Answer 3

这是一个使用抽象类的例子。

    public abstract class Publication 
    {
      private String _ISBN;
      private String _Title;
      private String _Publication;
      private float _Price;

      public String getISBN() { return _ISBN;}
      public void setISBN(String isbn)
      {
        _ISBN = isbn;
      }

      public String getTitle() { return _Title;}
      public void setTitle(String title)
      {
        _Title = title;
      }

      public String getTitle() { return _Title;}
      public void setTitle(String title)
      {
        _Title = title;
      } 

      public String getPublisher() { return _Publication;}
      public void setPublisher(String publication)
      {
        _Publication= publication;
      } 

       public float getPrice() { return _Price;}
       public void setPrice(float price)
       {
           _Price= price;
       } 
    }

    public class Book extends Publication
    {

    }  

    public class Magazine extends Publication
    {

    }  

//using the class
Book book = new Book();
book.getPrice();