Re: Exception misinformation

Hans_L wrote:

2) Using exceptions does not mean wrapping every method call in a try/catch block. The idea with exceptions is that they allow you to group things into logical units -- think of business transactions, or Transaction Script pattern. try/catch blocks only need to exist where you want them to exist. It allows you to decide what contexts are relevant for exceptions. Here's an example [that I think I've given before]: function hydrate(ResultSet $rs) { try {

    $this->setName($rs->getString(1));
    $this->setEmail($rs->getString(2));
    $this->setLoginCount($rs->getInt(3));
    $this->setPicture($rs->getBlob(4));
    $this->setLastLogin($rs->getTimestamp(5));
    $this->setSignature($rs->getString(6));
    $this->setPassword($rs->getString(7));

} catch (SQLException $e) {

     throw new PropelException("Error populating Person object.", $e);

} }

So... if an exception is thrown, does the block complete execution? or does it stop as soon as the exception is thrown? If the former is true, you need to try for exceptions whenever something important happens. For example, in a DB script I have, I need to be able to roll back anything I've submitted to the DB if something goes wrong. (I'm using linked tables.) Exceptions would be a huge mess if they allow my script to first populate all the data before I get notified that I'm in trouble. This wouldn't make sense to me. However, if the latter is the way it works, and an exception is simply notifying me that something minor failed that I don't care about (e.g., if I passed a roman numeral with illegal characters), then it breaks my whole script until I fix the input (which I may or may not have control of, esp. if I'm simply parsing existing data and I don't care if something minor fails). Exceptions force the developer to group calls into one break/all break groups. And while for something like a failed DB connection would amply justify an exception, there are very many errors that don't. So the way I see it, try() catch() is a lose/lose situation depending on what you want to do with it. That's why an error stack is so important and notices, too. Btw, since writing the above I was chatting on IRC and was told by meebey that when an exception is thrown (and filters down to the level of the try), execution is halted and catch is envoked. This is bad in many cases as I've mentioned above. Overuse of exceptions will make PEAR less than usable. Is that a death knell I hear in the distance? Klaus