我应该使用空返回值、检查异常或可能的空对象模式来设计以下API吗?

我来到一个API getStock 设计,在我没有很好的判断,我应该如何处理操作失败。

API将使我能够传递股票代码,如果成功,则返回股票。

我应该用吗? null returned value 指示操作失败,或 throwing checked exception 指示操作失败?或可能 Null Object Pattern ?为什么?

返回值为空

// User force to check the returned value each time.
// This happen when, stock server is down, network is down, 
// stockCode is not valid...
Stock stock = stockServer.getStock(stockCode);
if (stock != null) {
    // Success.
}

已检查异常

try {
    // User force to catch the exception each time.
    // This happen when, stock server is down, network is down,
    // stockCode is not valid...
    Stock stock = stockServer.getStock(stockCode);
    // Success.
} catch (StockNotFoundException ex) {
}

空对象模式

Stock stock = stockServer.getStock(stockCode);
// stock.getPrice(), stock.getVolume() will return 0...
// But when there is a need to check whether we are getting
// a null stock, we need to check 
// if (stock.getPrice() == 0.0 && stock.getVolume()...