重构：用委托替换继承

用委托替换继承重构允许 IntelliJ IDEA 从继承层次结构中删除类，同时保留父级的功能。IntelliJ IDEA 创建了一个私有的内部类，它继承了以前的超类或接口。通过新的内部类调用父节点的选定方法。

用委托替换继承重构示例

重构前：

// File Class.java
public class Class extends SuperClass {
    public int varInt;
    public void openMethod() {
        ...
    }
}

// File SuperClass.java
public abstract class SuperClass {
    public static final int CONSTANT=0;
    public abstract void openMethod();
    public void secretMethod() {
        ...
    }
}

重构后：

// File Class.java
public class Class {
    public int varInt;
    private final MySuperClass superClass = new MySuperClass();
    public SuperClass getSuperClass() {
        return superClass;
    }
    public void openMethod() {
        superClass.openMethod();
    }
    private class MySuperClass extends SuperClass {
        public void openMethod() {
            ...
        }
    }
}

// File SuperClass.java UNCHANGED
public abstract class SuperClass {
    public static final int CONSTANT=0;
    public abstract void openMethod();
    public void secretMethod() {
        ...
    }
}

要用委派替换继承，请按照下列步骤操作：