README.md
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# PHP Constraint Violations
This library provides an implementation of the [Notification Pattern](http://martinfowler.com/eaaDev/Notification.html)
with additional functionality to keep code DRY and to be more useful in the context of
[Domain-Driven Design](http://www.domaindrivendesign.org/) (DDD) and its value objects.
## Installation
Open a terminal, enter your project directory and execute the following command to add this package to your
dependencies:
```bash
$ composer require fleshgrinder/constraint-violations
```
This command requires you to have Composer installed globally, as explained in the
[installation chapter](https://getcomposer.org/doc/00-intro.md) of the Composer documentation.
## Usage
Most basic usage is as illustrated in the following example:
```php
$input = 'some data';
$errors = new ViolationCollector();
$warnings = new ViolationCollector();
if (some_validation($input) === false) {
$errors->addViolation('some message');
}
if (some_other_validation($input) === false) {
$warnings->addViolation('some other message');
}
// More validations ...
if ($warnings->hasViolations) {
echo "WARNINGS\n";
foreach ($warnings->getMessages() as $message) {
echo "{$message}\n";
}
}
if ($errors->hasViolations) {
echo "ERRORS\n";
foreach ($warnings->getMessages() as $message) {
echo "{$message}\n";
}
exit(1);
}
// Continue ...
```
Please have a look at the [wiki](https://github.com/fleshgrinder/php-constraint-violations/wiki) for more examples.
## Weblinks
- Martin Folwer: “_[Replacing Throwing Exceptions with Notification in Validations](http://martinfowler.com/articles/replaceThrowWithNotification.html)_”,
in _martinfowler.com_, December 9, 2014.
## License
[](https://opensource.org/licenses/MIT)