「こんにちは、アミーゴ！」
「こんにちは、リス船長さん！」
「兵士さん、その匂いがしますか？」
"いいえ、私はしません。"
「臭いはおそらくあなたの端末から来ています。そこで何をしているのか見てみましょう。」
「え？コードってどうして臭うの？」
「確かに、臭わないはずはありません...でも、臭いがすることはよくあります。」
「船長、私は船の新しい人事管理システムを開発しています。ほら、プロジェクトはほぼ準備ができています。」
「さあ、リファクタリングで禅を達成する時が来ました。そうして初めて、コードをクレンジングできるようになります。任務についてはエージェント IntelliJ IDEA に連絡してください。彼がすべての指示を与えます。」
「はい、先生！ご注文を遂行いたします、先生。」
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 1)
It's time for a little refactoring. Wikipedia says, "Refactoring
or reorganizing code is the process of changing the internal structure of a program, without
affecting its external behavior and with an aim to making it easier to understand.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 2)
2.1. Extract a subclass.
2.1.1. Add the Soldier class to the human package.
2.1.2. Get rid of the isSoldier field.
2.1.3. Move the necessary methods from Human to Soldier.
2.1.4. Update the Human constructor's signature.
2.2. Pull up the body of the constructor.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 3)
3.1. Push down a field. Push down the course field to the appropriate class. Make it private.
3.2. Push down a method. Push down the getter for the course field to the appropriate class.
3.3. Extract an interface.
3.3.1. Create an Alive interface in the human package.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 4)
4.1. Replace inheritance with delegation.
4.1.1. The University class must not inherit Student.
4.1.2. The University class must have a students list. Don't forget to initialize it.
4.1.3. Add a setter and getter for students.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 5)
5.1. Create a template method.
5.1.1. Add a String getPosition() method to the Human class. It should return the string "Person".
5.1.2. Override this method in the Student and Teacher classes. The method should return "Student" and "Teacher", respectively.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 6)
6.1. Replace a parameter with a set of specialized methods. Replace the Student class's setValue() method
with specialized setCourse() and setAverageGrade() methods.
6.2. Add a parameter. Add a double parameter to the getStudentWithAverageGrade() method so the average grade of the required student.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 7)
7.1. Parameterize a method. Replace the incAverageGradeBy01() and incAverageGradeBy02() methods
with an incAverageGrade(double delta) method.
7.2. Pass an entire object. Rewrite the addStudentInfo() method so that it
takes a Student object as an argument.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 8)
8.1. Remove a setter. Remove the setId() method. The id field should be set only when
the object is created.
8.2. Hide a method (field). Change the visibility of the nextId field to match
the area where it is used.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 9)
9.1. Self-encapsulate a field. Rewrite the incAverageGrade() method, using a setter and getter to access averageGrade.
9.2. Replace an array field with an object. Replace the int[] size array with an instance of a new Size type,
containing the following public fields: int height and int weight.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 10)
Understand the code in the car package.
10.1. Replace a constructor with a factory method.
10.1.1. Declare Truck, Sedan, and Cabriolet classes that inherit Car.
10.1.2. Add constructors that have an int numberOfPassengers constructors.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 11)
11.1. Replace an error code with an exception. Rewrite the fill(double numberOfGallons)
method to throw an Exception if there is an error.
11.2. Decompose a conditional expression.
11.2.1. Add and implement a method in the Car class that determines whether the passed date belongs to
summer.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 12)
12.1. Combine conditional expressions.
12.1.1. In the Car class, add a private method that indicates whether passengers can be carried:
boolean canPassengersBeCarried(). The method should return true if
the driver is available (isDriverAvailable) and there is fuel.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 13)
Understand the code in the user package.
13.1. Extract a method. Add a printInfo() method that displays the first and last name
on the console, formatted as follows -
First name: Jason;
Last name: Slater.
Replace the duplicate code in printUsers() with a method call.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 14)
14.1. Move a field. Replace the isAnnaMale and isRomanMale fields with a male field in the appropriate class.
Add a setter and getter for the new field (when choosing method names, consider the field type).
14.2. Extract a class.
14.2.1. Add an Address class to the user package.
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Java Multithreading, レベル 5, レッスン 16
Refactoring (part 15)
Great. You've mastered basic refactoring techniques: Pull up a field, pull up a method, Encapsulate a collection, extract a subclass, pull up the body of a constructor, push down a method, push down a field, extract an interface, collapse a hierarchy, replace inheritance with delegation.