Q: How to change exception message? Inside my code base I have a something like this:
function saveApples($apples) {
  try {
    write2DB($apples); // this function can throw Exception
  }
  catch (Exception $e) {
    throw $e;
  }
}

which works just fine.
What if I'd like to add some "context" info to exception message?
For example prepending the text: "Sorry, can't store apples: " to it?
UPDATE: To answer to DDeme comment, I suppose write2DB() function throws a meaningful exception, which I want to pass up...

A: Just add some text to the constructor.
e.g. 
function saveApples($apples) {
  try {
    write2DB($apples);
  }
  catch (Exception $e) {
    throw new Exception('Sorry, can\'t store apples', 0, $e);
  }
}

http://php.net/manual/en/language.exceptions.php
