#36 - Eager loading

maphper/datasource/mysqladapter.php

@@ -136,4 +136,5 @@ public function optimiseColumns($table) {
 		//Sometimes a second pass is needed, if a column has gone from varchar -> int(11) a better int type may be needed
 		if ($runAgain) $this->optimiseColumns($table);
 	}
+
 }

maphper/iterator.php

@@ -3,30 +3,30 @@
 namespace Maphper;
 
 class Iterator implements \Iterator {
-  private $array;
-  private $pk;
-  private $iterator = 0;
+	private $array;
+	private $pk;
+	private $iterator = 0;
 
-  public function __construct(array $array, $pk) {
-    $this->array = $array;
-    $this->pk = $pk;
-  }
+	public function __construct(array $array, $pk) {
+		$this->array = $array;
+		$this->pk = $pk;
+	}
 
-  public function current() {
+	public function current() {
 		return $this->array[$this->iterator];
 	}
 
 	public function key() {
-    if (count($this->pk) == 1) {
-  		$pk = end($this->pk);
-  		return $this->array[$this->iterator]->$pk;
-    }
-    else {
-      $current = $this->current();
-      return array_map(function($pkName) use ($current) {
-        return $current->$pkName;
-      }, $this->pk);
-    }
+		if (count($this->pk) == 1) {
+			$pk = end($this->pk);
+			return $this->array[$this->iterator]->$pk;
+		}
+		else {
+			$current = $this->current();
+			return array_map(function($pkName) use ($current) {
+				return $current->$pkName;
+			}, $this->pk);
+		}
 	}
 
 	public function next() {

maphper/maphper.php

@@ -61,8 +61,10 @@ private function getResults() {
 		$results = $this->dataSource->findByField($this->settings['filter'],
 			['order' => $this->settings['sort'], 'limit' => $this->settings['limit'], 'offset' => $this->settings['offset'] ]);
 
+		$siblings = new \ArrayObject();
+
 		$results = array_map([$this, 'createNew'], $results);
-		$results = array_map([$this, 'wrap'], $results);
+		array_walk($results, [$this, 'wrap'], $siblings);
 
 		return $results;
 	}
@@ -140,16 +142,16 @@ private function processDates($obj) {
 		return $injector->replaceDates($obj);
 	}
 
-	private function wrap($object) {
+	private function wrap($object, $key = null, $siblings = null) {
 		//see if any relations need overwriting
 		foreach ($this->relations as $name => $relation) {
 			if (isset($object->$name) && !($object->$name instanceof \Maphper\Relation) ) {
 				//After overwriting the relation, does the parent object ($object) need overwriting as well?
 				if ($relation->overwrite($object, $object->$name)) $this[] = $object;
-
 			}
 
-			$object->$name = $relation->getData($object);
+			$object->$name = $relation->getData($object, $siblings);
+			//var_dump($siblings);
 		}
 		return $object;
 	}

maphper/relation/one.php

@@ -7,6 +7,7 @@ class One implements \Maphper\Relation {
 	private $parentObject;
 	private $criteria = [];
 	private $data;
+	private $siblings = [];
 
 	public function __construct(\Maphper\Maphper $mapper, $parentField, $localField, array $criteria = []) {
 		$this->mapper = $mapper;
@@ -15,10 +16,14 @@ public function __construct(\Maphper\Maphper $mapper, $parentField, $localField,
 		$this->criteria = $criteria;
 	}
 
-	public function getData($parentObject) {
+	public function getData($parentObject, &$siblings = null) {
 		//Don't actually fetch the related data, return an instance of $this that will lazy load data when __get is called
 		$clone = clone $this;
 		$clone->parentObject = $parentObject;
+		$siblings[] = $clone;
+		$clone->siblings = $siblings;
+
+	//	var_dump($siblings);
 		return $clone;
 	}
 
@@ -27,12 +32,41 @@ private function lazyLoad() {
 
 			if ($this->parentObject == null) throw new \Exception('Error, no object set');
 
-			if ($this->criteria) $this->data = $this->mapper->filter($this->criteria)->filter([$this->localField => $this->parentObject->{$this->parentField}])->item(0);
-			else $this->data = $this->mapper->filter([$this->localField => $this->parentObject->{$this->parentField}])->item(0);
+			$this->eagerLoad();
+
 		}
 		return $this->data;
 	}
 
+	private function eagerLoad() {
+		$recordsToLoad = [];
+		//Get a list of records by FK to eager load	
+		foreach ($this->siblings as $sibling) {
+			$recordsToLoad[] = $sibling->parentObject->{$sibling->parentField};
+		}
+
+		$recordsToLoad = array_unique($recordsToLoad);
+		//Fetch the results so they're in the cache for the corresponding maphper object
+		if ($this->criteria) $results = $this->mapper->filter($this->criteira)->filter([$this->localField => $recordsToLoad]);
+		else $results = $this->mapper->filter([$this->localField => $recordsToLoad]);
+
+		$cache = [];
+		foreach ($results as $result) {
+			$cache[$result->{$this->localField}] = $result; 
+		}
+
+		foreach ($this->siblings as $sibling) {
+			$sibling->data = $cache[$sibling->parentObject->{$this->parentField}];
+		}
+		/*
+		foreach ($this->siblings as $sibling) {
+			if ($sibling->criteria) $sibling->data = $sibling->mapper->filter($sibling->criteria)->filter([$sibling->localField => $sibling->parentObject->{$sibling->parentField}])->item(0);
+			else $sibling->data = $sibling->mapper->filter([$sibling->localField => $sibling->parentObject->{$this->parentField}])->item(0);
+		}
+		*/
+
+	}
+
 	public function __call($func, array $args = []) {
 		if ($this->lazyLoad() == null) return '';
 		return call_user_func_array([$this->lazyLoad(), $func], $args);

tests/MySqlDatabaseTest.php

@@ -1132,4 +1132,24 @@ public function testInsertNoEditModeNoDefaultValue() {
 
 
 	}
+
+/*
+	//Need some way of asserting this happens
+	public function testEagerLoad() {
+		$this->populateBlogsAuthors();
+
+		$blogs = new \Maphper\Maphper($this->getDataSource('blog', 'id', ['editmode' => true]));
+		$authors = new \Maphper\Maphper($this->getDataSource('author'));
+		$blogs->addRelation('author', new \Maphper\Relation\One($authors, 'authorId', 'id'));
+
+		//This should issue two queries
+		foreach ($blogs as $blog) {
+			echo 'iteration';
+			$aName = $blog->author->name;
+
+		}
+
+	}
+
+*/
 }