Add example for persistable objects

Author: alcaeus

examples/persistable.php

@@ -0,0 +1,139 @@
+<?php
+declare(strict_types=1);
+
+namespace MongoDB\Examples;
+
+use MongoDB\BSON\ObjectId;
+use MongoDB\BSON\Persistable;
+use MongoDB\Client;
+use stdClass;
+
+use function array_search;
+use function dirname;
+use function getenv;
+use function var_dump;
+
+require dirname(__FILE__) . '/../vendor/autoload.php';
+
+class Entry implements Persistable
+{
+    /** @var ObjectId */
+    private $id;
+
+    /** @var string */
+    private $name;
+
+    /** @var array<Email> */
+    private $emails = [];
+
+    public function __construct(string $name)
+    {
+        $this->id = new ObjectId();
+        $this->name = $name;
+    }
+
+    public function getId(): ObjectId
+    {
+        return $this->id;
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name): void
+    {
+        $this->name = $name;
+    }
+
+    public function getEmails(): array
+    {
+        return $this->emails;
+    }
+
+    public function addEmail(Email $email): void
+    {
+        $this->emails[] = $email;
+    }
+
+    public function deleteEmail(Email $email): void
+    {
+        $index = array_search($email, $this->emails, true);
+        if ($index === false) {
+            return;
+        }
+
+        unset($this->emails[$index]);
+    }
+
+    public function bsonSerialize(): stdClass
+    {
+        return (object) [
+            '_id' => $this->id,
+            'name' => $this->name,
+            'emails' => $this->emails,
+        ];
+    }
+
+    public function bsonUnserialize(array $data): void
+    {
+        $this->id = $data['_id'];
+        $this->name = (string) $data['name'];
+        $this->emails = $data['emails']->getArrayCopy(); // Emails will be passed as a BSONArray instance
+    }
+}
+
+class Email implements Persistable
+{
+    /** @var string */
+    private $type;
+
+    /** @var string */
+    private $address;
+
+    public function __construct(string $type, string $address)
+    {
+        $this->type = $type;
+        $this->address = $address;
+    }
+
+    public function getType(): string
+    {
+        return $this->type;
+    }
+
+    public function getAddress(): string
+    {
+        return $this->address;
+    }
+
+    public function bsonSerialize(): stdClass
+    {
+        return (object) [
+            'type' => $this->type,
+            'address' => $this->address,
+        ];
+    }
+
+    public function bsonUnserialize(array $data): void
+    {
+        $this->type = (string) $data['type'];
+        $this->address = (string) $data['address'];
+    }
+}
+
+$entry = new Entry('alcaeus');
+$entry->addEmail(new Email('work', '[email protected]'));
+$entry->addEmail(new Email('private', '[email protected]'));
+
+$client = new Client(getenv('MONGODB_URI') ?: 'mongodb://127.0.0.1/');
+
+$collection = $client->test->coll;
+$collection->drop();
+
+$collection->insertOne($entry);
+
+$foundEntry = $collection->findOne([]);
+
+var_dump($foundEntry);