Book class in Java with Enum and a HashSet

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英文:

Book class in Java with Enum and a HashSet

问题

以下是翻译好的部分：

  1. public class Book {
  3.     enum Type {
  4.         Classic_Literature, THRILLER, Psychology, MANUAL, Self_Improvement;
  5.     }
  6.     String name;
  7.     String author;
  8.     double price;
  10.     public Book(String name, String author, double price) {
  11.         this.name = name;
  12.         this.author = author;
  13.         this.price = price;
  14.     }
  16.     public String get.name() {
  17.         return name;
  18.     }
  19. }
  1. public class Books extends Book {
  3.     public Books(String name, String author, double price) {
  4.         super(name, author, price);
  5.     }
  7.     public static void main(String[] args) {
  8.         HashSet<String> books = new HashSet<>();
  9.         books.add("Baltagul");                //classical literature
  10.         books.add("Morometii");               //classical literature
  11.         books.add("Dezvoltarea personalitatii");
  12.         books.add("Criminalul ABC");
  13.         books.add("In mintea ta");
  14.         books.add("Abecedar");
  15.         books.add("Assassin's Creed Revelations");
  16.         books.add("In mintea lui");
  17.         books.add("Culegere Mate");
  18.         books.add("Public Speaking");
  19.     }
  20. }

关于问题：

  • 我该如何创建一个链接，以便可以打印出所有来自“Literatura clasica”（古典文学）的书籍？
  • 我不太清楚如何实现这样一个方法。

（注意：我已经移除了代码部分的翻译，只提供了代码的英文原文。）

英文:

Need to create a book class with some features:name,author,price.The type of the book must be an enum and also i need to add some books using hashset.

  1. public class Book {
  3.     enum Type {
  4.         Classic_Literature, THRILLER, Psychology, MANUAL, Self_Improvement;
  5.     }
  6.         String name;
  7.         String author;
  8.         double price;
  9.        
  11.     public Book(String name, String author, double price) {
  12.         this.name = name;
  13.         this.author = author;
  14.         this.price = price;
  16.   	  }
  18.     public String get.name() {
  19.    return name;
  21.     }
  22. }
  1. public class Books extends Book {
  4.     public Books(String name, String author, double price) {
  5.         super(name, author, price);
  6.     }
  8.     public static void main(String[] args) {
  9.         HashSet&lt;String&gt; books = new HashSet&lt;&gt;();
  10.         carti.add(&quot;Baltagul&quot;);                //classical literature
  11.         carti.add(&quot;Morometii&quot;);               //classical literature
  12.         carti.add(&quot;Dezvoltarea personalitatii&quot;);
  13.         carti.add(&quot;Criminalul ABC&quot;);
  14.         carti.add(&quot;In mintea ta&quot;);
  15.         carti.add(&quot;Abecedar&quot;);
  16.         carti.add(&quot;Assassin&#39;s Creed Revelations&quot;);
  17.         carti.add(&quot;In mintea lui&quot;);
  18.         carti.add(&quot;Culegere Mate&quot;);
  19.         carti.add(&quot;Public Speaking&quot;);
  20.     }
  21. }

The books are in Romanian so don't mind them.

My problem is:
-How can I make a link so that I can print out all books from "Literatura clasica"(Classical Literature)?

I don't exactly know how to implement such a method.

答案1

得分: 1

  1. public class Book {
  3.     enum Type {
  4.         Classic_Literature, THRILLER, Psychology, MANUAL, Self_Improvement;
  5.     }
  7.     String name;
  8.     String author;
  9.     double price;
  10.     Type type;
  12.     public Book(String name) {
  13.         this.name = name;
  14.     }
  16.     public Book(String name, Type type) {
  17.         this.name = name;
  18.         this.type = type;
  19.     }
  21.     public String getName() {
  22.         return name;
  23.     }
  24. }
  1.     public static void main(String[] args) {
  2.         HashSet<Book> books = new HashSet<>();
  3.         books.add(new Book("Baltagul", Book.Type.Classic_Literature));                //古典文学
  4.         books.add(new Book("Morometii", Book.Type.Classic_Literature));               //古典文学
  5.         books.add(new Book("Dezvoltarea personalitatii"));
  6.         books.add(new Book("Criminalul ABC"));
  7.         books.add(new Book("In mintea ta"));
  9.         //在这里检索古典文学书籍
  11.         Set<Book> classicBooks = books.stream()
  12.                 .filter(b -> b.type == Book.Type.Classic_Literature)
  13.                 .collect(Collectors.toSet());
  14.     }
英文:

Some ideas to start improving your code.....

  1. public class Book {
  3.     enum Type {
  4.         Classic_Literature, THRILLER, Psychology, MANUAL, Self_Improvement;
  5.     }
  7.     String name;
  8.     String author;
  9.     double price;
  10.     Type type;
  12.     public Book(String name) {
  13.         this.name = name;
  14.     }
  16.     public Book(String name, Type type) {
  17.         this.name = name;
  18.         this.type = type;
  19.     }
  21.     public String getName() {
  22.         return name;
  23.     }
  24. }   
  1.     public static void main(String[] args) {
  2.         HashSet&lt;Book&gt; books = new HashSet&lt;&gt;();
  3.         books.add(new Book(&quot;Baltagul&quot;, Book.Type.Classic_Literature));                //classical literature
  4.         books.add(new Book(&quot;Morometii&quot;, Book.Type.Classic_Literature));               //classical literature
  5.         books.add(new Book(&quot;Dezvoltarea personalitatii&quot;));
  6.         books.add(new Book(&quot;Criminalul ABC&quot;));
  7.         books.add(new Book(&quot;In mintea ta&quot;));
  9.         //here you retrieve the classical literature books
  11.         Set&lt;Book&gt; classicBooks = books.stream()
  12.                 .filter(b -&gt; b.type == Book.Type.Classic_Literature)
  13.                 .collect(Collectors.toSet());
  14.     }

答案2

得分: 0

有关于代码的一些误解。
<br>

  1. 将物品作为书籍，但在主函数中没有使用它。
    <br>那么为什么进行了定义？
    也许需要这样：
    <br>//书籍集合
    <br>HashSet&lt;Book&gt; books = new HashSet&lt;&gt;();
    <br>2. 为什么Books应该扩展为Book？
    在这里不需要。
    <br>Books只是一个常规类，在其中通过HashSet进行聚合。
    <br>3. 基本的Book实例化。
    也许需要这样：
    <br>books.put(new Book("Poezii", "Eminescu", 123))
    <br>.4. 书籍分类在哪里链接？
    <br>也许可以修改构造函数：
    <br>public Book(String name, String author, double price, BookType bookType)
    <br>然后进行适当的实例化
    <br>.5. 显示特定分类内的书籍。
    只需在集合内使用常规循环，并仅对特定的BookType（例如：Classic_Literature）进行验证。
英文:

There are some misconceptions on the code.
<br>

  1. Have the item as book and not use it within main.
    <br>So why was defined ?
    Maybe this is required:
    <br>//colection of books
    <br> HashSet&lt;Book&gt; books = new HashSet&lt;&gt;();
    <br>2. Why Books should extends Book ?
    No need here.<br> Books is just a regular class where you do aggregation via HashSet
    <br>3.Basic Book instantiation.
    Maybe it's needed:
    <br> books.put(new Book(&quot;Poezii&quot;, &quot;Eminescu&quot;, 123))
    <br>.4.Where is the classification of book linked ?
    <br>Maybe altering the constructor:
    <br>public Book(String name, String author, double price, BookType bookType)<br> and after do a proper instantiation
    <br>.5. Display the books within a classification.<br> Just use a regular loop within collection and validate only for a certain BookType (eg: Classic_Literature)
    ...

huangapple
  • 本文由 发表于 2020年4月7日 04:43:45
  • 转载请务必保留本文链接：https://go.coder-hub.com/61068650.html
  • java
  • oop
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