java - 如何结合异常来摆脱重复代码？

Question

如何尽量减少代码中重复抛异常的代码:

public R get(int index) throws IndexException {
  if (!((0 <= index) && (index < this.info.length))) {
    throw new IndexException();
  }
  return this.info[index];
}

public void set(int index, R r) throws IndexException {
  if (!((0 <= index) && (index < this.info.length))) {
    throw new IndexException();
  }
  this.info[index] = r;
}

Answer 1

创建一个会抛出异常的方法:

private void checkBounds(int index) throws IndexException {
  if (index < 0 || index >= info.length) {
     throw new IndexException();
  }
}

然后你可以调用它:

public R get(int index) throws IndexException {
  checkBounds(index);
  return this.info[index];
}

public void set(int index, R r) throws IndexException {
  checkBounds(index);
  this.info[index] = r;
}