The document discusses how "anemic objects" can kill object-oriented programming (OOP). It begins by contrasting procedural programming with OOP, then defines anemic objects as classes that only contain getter and setter methods for data but no other business logic. The document argues that anemic objects still result in imperative and procedural code, fail to encapsulate data with semantic meaning, and don't solve the growing complexity that OOP was intended to address. It provides an example to demonstrate how to refactor code using fully-featured objects that encapsulate behavior and data together.

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How Anemic Objects
Kill OOP
Yegor Bugayenko

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1. Procedural programming
2. Object thinking (programming)?
3. Practical example
4. What is anemic model?
5. Refactoring
6. Let’s discuss

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1. Code is king (how)
2. Imperative
3. Same as hardware
4. Data is visible

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1. Object is king (what)
2. Declarative
3. Same as real world
4. Data is hidden

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a = 3 + 5;
new Sum(3, 5);

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complexity is growing
because
data has no semantic

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OOP was supposed to
become a solution

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“Objects expose
behavior and data”
— article about
Procedural Programming

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API DB
book1
book2
book1 = API.fetch();
book2.isbn = book1.isbn;
book2.title = book1.isbn;
DB.save(book2);

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class Book {
public String isbn;
public String title;
}

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class Book {
private String isbn;
private String title;
public String getIsbn();
public String getTitle();
public void setIsbn(String);
public void setTitle(String);
}

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1. Data is still visible
2. Still imperative
3. No semantic

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API
DB
new DBBook(new APIBook());

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class APIBook implements Book {
String title() {
// make HTTP request
// parse JSON and
// return title
}
}

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class DBBook implements Book {
private Book book;
String title() {
String title = this.book.title();
// save title to the DB
return title;
}
}

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what do you
think?