1: <?php
 2: namespace NGS\Patterns;
 3: 
 4: require_once(__DIR__.'/Identifiable.php');
 5: require_once(__DIR__.'/../Client/CrudProxy.php');
 6: 
 7: use NGS\Client\CrudProxy;
 8: use NGS\Client\DomainProxy;
 9: use NGS\Patterns\Identifiable;
10: use NGS\Patterns\AggregateDomainEvent;
11: 
12: /**
13:  * Aggregate root is a meaningful object in the domain.
14:  * It can be viewed as a write boundary for entities and value objects
15:  * that will maintain write consistency.
16:  * <p>
17:  * Usually it represents a single table, but can span several tables
18:  * and can be used like document or similar data structure.
19:  * Since every aggregate is also an entity, it has a unique
20:  * identification represented by its URI.
21:  * <p>
22:  * DSL example:
23:  * <blockquote><pre>
24:  * module Todo {
25:  *   aggregate Task {
26:  *     timestamp startedAt;
27:  *     timestamp? finishedAt;
28:  *     int? priority;
29:  *     List<Note> notes;
30:  *   }
31:  *   value Note {
32:  *     date entered;
33:  *     string remark;
34:  *   }
35:  * }
36:  * </pre></blockquote>
37:  */
38: abstract class AggregateRoot extends Identifiable
39: {
40:     /**
41:      * Persists object on the server.
42:      * Insert is performed if object's URI is not set, otherwise, if URI is set,
43:      * current object is updated.
44:      *
45:      * @return AggregateRoot Persisted object
46:      */
47:     public function persist()
48:     {
49:         return $this->getURI() === null
50:             ? CrudProxy::instance()->create($this)
51:             : CrudProxy::instance()->update($this);
52:     }
53: 
54:     /**
55:      * Deletes object from the server
56:      *
57:      * @return AggregateRoot Deleted object
58:      * @throws \LogicException If object instance was created, but not persisted
59:      */
60:     public function delete()
61:     {
62:         if ($this->URI===null) {
63:             throw new \LogicException('Cannot delete instance of root "'.get_class($this).'" because it\'s URI was null.');
64:         }
65:         return CrudProxy::instance()->delete(get_called_class(), $this->URI);
66:     }
67: 
68:     /**
69:      * Applies aggregate domain event on object
70:      *
71:      * @param \NGS\Patterns\AggregateDomainEvent $event
72:      * @return AggregateRoot New instance of AggregateRoot with updated values
73:      * after applying event
74:      * @throws \LogicException If object instance was created, but not persisted
75:      */
76:     public function apply(AggregateDomainEvent $event)
77:     {
78:         $proxy = DomainProxy::instance();
79:         if($this->URI===null) {
80:             throw new \LogicException('Event '.get_class($event).' cannot be applied on instance of root "'.get_class($this).'" because it\'s URI was null.');
81:         }
82:         return $proxy->submitAggregateEvent($event, $this->URI);
83:     }
84: }
85: