phpbuilder - Error Handling

Hi all, here some ideas on error handling based on what I have seen in the phpbuilder article http://www.phpbuilder.com/columns/sean20000712.php3?page=3. I guess it shown only a small subset of your ideas Stig, does it? I like the idea of creating error objects very much and I played with it in my last project. I adopted quite a lot of the java way. All error classes are inherited from a common baseclass "exception". instance variables: $CLASSNAME - overriden, used to classify exceptions (IO, User, ...) $ERROR_MESSAGE_PREFIX - overriden, some prefix added to the exception $ERROR_PREPEND - some prepend and append for PHP3 users that do not $ERROR_APPEND - have trigger_error() to customize the output $message - error message itself $file - Filename where the error occured $line - Line number where the error occured, method name is not neccessary as long as you have the line number $DIE_ON_ERROR - for debugging purpose it should be there $AUTO_PRINT_ERROR - same as $DIE_ON_ERROR $LEVEL - error level used when trigger_error() gets called $TRIGGER_ERROR - turns the call to trigger_error() on and off I like having $DIE_ON_ERROR and $AUTO_PRINT_ERROR very much because it makes debugging easy. Just turn it on an you'll see all messages. All other variables are self explaining. methods: void constructor ( string $message, [string $file, int $line]) Sets some instance variables (message, file, line) and calls trigger_error(), printLocalizedMessage() and die() if necessary. string getMessage( void ) Returns the current error message. Uses ERROR_PREPEND, ERROR_MESSAGE_PREFIX, message and ERROR_APPEND to build the message. string getLocalizedMessage ( void ) Same as getMessage() plus line numbwe and filename. string getType( void ) Returns the $CLASSNAME. The classname should always start with "Exception" or maybe "Error" followed by a descriptive name. The $CLASSNAME allows you to distinguish beetween a valid return type and an error... What does a derived class MyPackageException" look like? instance variables: $CLASSNAME = "ExceptionMyPackage"; $ERROR_MESSAGE_PREPEND = "Error in my package: "; $LEVEL = USER_ERROR; [$ERROR_PREPEND] [$ERROR_APPEND] methods: void constructor ( string $message [, string $file, int $line] ) Just calls the constructor of the base class. How do I "throw" an error? All my classes that might "throw" an error have a public instance variables $err which holds the last exception object. Whenever an error occurs the method saves the exception in $this->err and tries to return some usefull value (false, empty array etc.) to preevent errors that appear because an unexpected datatype gets returned. Anyway this is not necessary for PEAR. Simply do: 'return MyPackageException("trouble somewhere", __FILE__, __LINE__);'. How do I "catch" an error? $ok = DB::connect(); if ( is_object($ok) && "Exception" == substr(get_classname($ok), ??end of beginning?? ) ) { $msg = $ok->getLocalizedMessage(); # $ok->printLocalizedMessage(); } Well, the sketched way is not perfect a real throw-catch construct would be much better. Nevertheless it is a way you can handle exceptions quite powerful and flexible in PHP3 and PHP4. Stig are you planning to provide a set of default Exceptions? I would like to see this ones: IOException FileNoPermissionException FileNotFoundException RuntimeException NoSuchMethodException InvalidParameterException Ulf