最终未初始化字段的抽象类 [英] Abstract class with final uninitialized field

问题描述

我想知道下面的代码是否有意义，因为编译器警告空白的最终字段对象可能尚未初始化。有没有更好的方法呢？

I was wondering if the below code makes any sense, since the compiler warns that "the blank final field objects may not have been initialized". Is there a better way of doing this?

public abstract Test {
  protected final ArrayList<Object> objects;
}

public TestSubA extends Test {

  public TestSubA() {
    objects = new ArrayList<Objects>(20);
    // Other stuff
  }
}

public TestSubB extends Test {

  public TestSubB() {
    objects = new ArrayList<Objects>(100);
    // Other stuff
  }
}

推荐答案

我会将字段设为final并强制构造函数传递值：

I would make the field final and force the constructors to pass the value up:

public abstract class Test {
  private final ArrayList<Object> objects;

  protected ArrayList<Object> getObjects() {
    return objects;
  }

  protected Test(ArrayList<Object> objects) {
    this.objects = objects;
  }
}

public class TestSubA extends Test {

  public TestSubA() {
    super(new ArrayList<Object>(20));
    // Other stuff
  }
}

public class TestSubB extends Test {

  public TestSubB() {
    super(new ArrayList<Object>(100));
    // Other stuff
  }
}

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