03-exceptions.cfc

/**
 * This exercise goes over:
 *     + Catching exceptions the traditional way
 *     + Catching exceptions in asynchronous code
 *     + Recovering from exceptions
 *     + Built in LogBox logging
 *     + Handling both results and errors in the same callback
 *
 * You can run this exercise from the root in CommandBox by running:
 *     `task run exercises/03-exceptions.cfc`
 *
 * You can use the `print` helper provided by CommandBox to log messages.
 * (Use `print.line( "message" ).toConsole()` if you're not familiar with it.)
 * Make sure to end with `.toConsole()` so your message is flushed
 * to the console the moment it is printed.
 */
component extends="../BaseTask" {

	/**
	 * Create a future that throws an exception.
	 * Catch this exception using a `try` / `catch` statement when calling `future.get()`.
	 *
	 * Question: What is the exception type in the `catch` statement?
	 */
	function partOne(){
		return;
	}

	/**
	 * Create a future that throws an exception.
	 * Catch this exception.
	 * Log a friendly error message to the console.
	 *
	 * Question: What is the exception type in the asynchronous `catch`?
	 */
	function partTwo(){
		return;
	}

	/**
	 * Create a future that may throw an exception using the `fakeAjax` helper.
	 * Catch this exception. Return the a default quote of your choosing from this step.
	 * Output the value of the pipeline to the console.
	 */
	function partThree(){
		return;
	}

	/**
	 * Create a future that may throw an exception using the `fakeAjax` helper.
	 * Handle both the error case and the success case at the same time.
	 * In the error case, use a default quote of your choosing.
	 * In the success case, use the passed in quote.
	 * Output the quote to the console.
	 */
	function partFour(){
		return;
	}

	/**
	 * Create a future that may throw an exception using the `fakeAjax` helper.
	 * Catch this exception. Return the a default quote of your choosing from this step.
	 * Process the quote value by passing it to `flakyAnalyticsRequest`.
	 * Catch this exception. Return the current quote value.
	 * Output the value of the pipeline to the console.
	 */
	function partFive(){
		return;
	}

	function run(){
		print.blueLine( "Running all `03-exceptions` exercises" ).toConsole();
		print
			.yellowLine( "Press Ctrl-C to exit" )
			.line()
			.toConsole();

		partOne();
		partTwo();
		partThree();
		partFour();
		partFive();

		while ( true ) {
			if ( !isNull( checkInterrupted() ) ) {
				return;
			}
			sleep( 100 );
		}
	}

	private string function fakeAjax(){
		sleep( randRange( 300, 1500 ) );
		if ( randRange( 1, 2 ) == 1 ) {
			var errors = [
				"Server is down",
				"Database is down",
				"Request timeout",
				"Out for lunch"
			];
			throw( errors[ randRange( 1, errors.len() ) ] );
		}
		var quotesPath = expandPath( "/commandbox" ) & "/system/Quotes.txt";
		var quotes     = fileRead( quotesPath ).listToArray( chr( 13 ) & chr( 10 ) );
		return quotes[ randRange( 1, quotes.len() ) ];
	}

}