IcingaRelatedObject: new helper class

library/Director/Objects/IcingaRelatedObject.php

@@ -0,0 +1,208 @@
+<?php
+
+namespace Icinga\Module\Director\Objects;
+
+use Icinga\Exception\ProgrammingError;
+use Icinga\Module\Director\Objects\IcingaObject;
+
+/**
+ * Related Object
+ * 
+ * This class comes in handy when working with simple foreign key references. In
+ * contrast to an ORM it helps to deal with lazy-loaded objects in a way allowing
+ * us to render objects with references which to no longer (or not yet) exist
+ */
+class IcingaRelatedObject
+{
+    /** @var IcingaObject Main object with (optional) relation */
+    protected $owner;
+
+    /** @var int Related object id */
+    protected $id;
+
+    /** @var int Related object name */
+    protected $name;
+
+    /** @var int Relation property name, e.g. 'host' */
+    protected $key;
+
+    /** @var int Relation property, e.g. 'host_id' */
+    protected $idKey;
+
+    /** @var IcingaObject Related object once loaded */
+    protected $object;
+
+    /** @var string Related class name */
+    protected $className;
+
+    /**
+     * IcingaRelatedObject constructor
+     *
+     * @param IcingaObject $owner Main object referring a related one
+     * @param string       $key   Main objects (short) property name for this
+     */
+    public function __construct(IcingaObject $owner, $key)
+    {
+        $this->owner = $owner;
+        $this->key   = $key;
+        $this->idKey = $key . '_id';
+    }
+
+    /**
+     * Set a specific id
+     *
+     * @param $id int
+     *
+     * @return self
+     */
+    public function setId($id)
+    {
+        if (! is_int($id)) {
+            throw new ProgrammingError(
+                'An id must be an integer'
+            );
+        }
+
+        if ($this->object !== null) {
+            if ($this->object->id === $id) {
+                return $this;
+            } else {
+                $this->object = null;
+            }
+        }
+
+        if ($this->object === null) {
+            $this->name = null;
+        }
+
+        $this->id = $id;
+        $this->owner->set($this->getRealPropertyName(), $id);
+
+        return $this;
+    }
+
+    /**
+     * Return the related objects id
+     *
+     * @return int
+     */
+    public function getId()
+    {
+        if ($this->id === null) {
+            $this->id = $this->getObject()->id;
+        }
+
+        return $this->id;
+    }
+
+    /**
+     * Lazy-load the related object
+     *
+     * @return IcingaObject
+     */
+    public function getObject()
+    {
+        if ($this->object === null) {
+            $class = $this->getClassName();
+
+            if ($this->name === null) {
+                if ($id = $this->getId()) {
+                }
+            } else {
+                $this->object = $class::load($this->name, $this->
+            }
+        }
+        return $this->object;
+    }
+
+    /**
+     * The real property name pointing to this relation, e.g. 'host_id'
+     *
+     * @return string
+     */
+    public function getRealPropertyName()
+    {
+        return $this->key . '_id';
+    }
+
+    /**
+     * Full related class name
+     *
+     * @return string
+     */
+    public function getClassName()
+    {
+        if ($this->className === null) {
+            $this->className = __NAMESPACE__ . '\\' . $this->getShortClassName();
+        }
+
+        return $this->className;
+    }
+
+    /**
+     * Related class name relative to Icinga\Module\Director\Objects
+     *
+     * @return string
+     */
+    public function getShortClassName()
+    {
+        return $this->owner->getRelationObjectClass($this->key);
+    }
+
+    /**
+     * Set a related property
+     *
+     * This might be a string or an object 
+     * @param $related string|IcingaObject
+     * @throws ProgrammingError
+     *
+     * return self
+     */
+    public function set($related)
+    {
+        if (is_string($related)) {
+            $this->name = $related;
+        } elseif (is_object($related)) {
+            if ($related instanceof $this->getClassName()) {
+                $this->object = $related;
+                $this->name = $object->object_name;
+                $this->id = $object->id;
+            } else {
+                throw new ProgrammingError(
+                    'Trying to set a related "%s" while expecting "%s"',
+                    get_class($related),
+                    $this->getShortClassName()
+                );
+            }
+        } else {
+            throw new ProgrammingError(
+                'Related object can be name or object, got: %s',
+                var_export($related, 1)
+            );
+        }
+
+        return $this;
+    }
+
+    /**
+     * Get the name of the related object
+     *
+     * @return string
+     */
+    public function getName()
+    {
+        if ($this->name === null) {
+            return $this->owner->{$this->key};
+        } else {
+            return $this->name;
+        }
+    }
+
+    /**
+     * Conservative constructor to avoid issued with PHP GC
+     */
+    public function __construct()
+    {
+        unset($this->owner);
+    }
+}