IntelliJ IDEA 2018.2 Help

Extract Superclass

The Extract Superclass lets you either create a superclass based on an exiting class or you can rename the original class so it becomes an implementation for the newly created superclass. In this case, IntelliJ IDEA changes all original class usages to use a superclass where possible.

Fields and methods in the original class can be moved to the superclass. Also for a method, you can transfer only the method declaration but not the implementation declaring the method as abstract in the superclass. As a result, you will have the superclass and the original class inherited from the superclass.

  1. Open the class in the editor and from the main menu select Refactor | Extract | Superclass.
  2. In the dialog that opens, specify a name for your class, location and class members that you want to include to form your superclass. Select the Make abstract checkbox to leave the method implementation within the current class, and declare it abstract in the extracted superclass. Click Refactor.

Example

BeforeAfter
// File Class.java public class Class { public int varInt; private double varDouble; public static final int CONSTANT = 0; public void publicMethod() { ... } public void hiddenMethod() { ... } public void setVarDouble(double var) { this.varDouble = var; } public double getVarDouble() { return varDouble; } }
// File Class.java public class Class extends SuperClass { public int varInt; public void publicMethod() { ... } public void hiddenMethod() { ... } } // NEW file SuperClass.java public abstract class SuperClass { private double varDouble; public static final int CONSTANT = 0; public abstract void publicMethod(); public void setVarDouble(double var) { this.varDouble = var; } public double getVarDouble() { return varDouble; } }
Last modified: 18 June 2018

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