Adding active record implementation.

1 files changed, 262 insertions, 0 deletions

diff --git a/framework/Data/ActiveRecord/TActiveRecordStateRegistry.php b/framework/Data/ActiveRecord/TActiveRecordStateRegistry.php
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+++ b/framework/Data/ActiveRecord/TActiveRecordStateRegistry.php
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+<?php
+/**

+ * TActiveRecordStateRegistry class file.

+ *

+ * @author Wei Zhuo <weizhuo[at]gmail[dot]com>

+ * @version $Id$

+ * @package System.Data.ActiveRecord

+ */

+

+/**

+ * Active record Unit of Work class and Identity Map.

+ *

+ * Maintains a list of objects affected by a business transaction and

+ * coordinates the writing out of changes and the resolution of concurrency problems.

+ *

+ * This registry keeps track of everything you do during a business transaction

+ * that can affect the database. When you're done, it figures out everything that

+ * needs to be done to alter the database as a result of your work.

+ *

+ * The object can only be in one of the four states: "new", "clean", "dirty" or "removed".

+ * A "new" object is one that is created not by loading the record from database.

+ * A "clean" object is one that is created by loading the record from datase.

+ * A "dirty" object is one that is marked as dirty or a "clean" object that has

+ * its internal state altered (done by using == object comparision).

+ * A "removed" object is one that is marked for deletion.

+ *

+ * See the "Active Record Object States.png" in the docs directory for state

+ * transition diagram.

+ *

+ * @author Wei Zhuo <weizho[at]gmail[dot]com>

+ * @version $Id$

+ * @package System.Data.ActiveRecord

+ * @since 3.1

+ */

+class TActiveRecordStateRegistry

+{

+	private $_cleanObjects=array();

+	private $_removedObjects;

+	private $_cachedObjects=array();

+	/**

+	 * Initialize the registry.

+	 */

+	public function __construct()

+	{

+		$this->_removedObjects = new TList;

+	}

+

+	/**

+	 * Get the cached object for given type and row data. The cached object

+	 * must also be clean.

+	 * @param mixed row data fetched

+	 * @return TActiveRecord cached object if found, null otherwise.

+	 */

+	public function getCachedInstance($data)

+	{

+		$key = $this->getObjectDataKey($data);

+		if(isset($this->_cachedObjects[$key]))

+		{

+			$obj = $this->_cachedObjects[$key];

+			if($this->getIsCleanObject($obj))

+				return $obj;

+		}

+	}

+

+	/**

+	 * Cache the object that corresponding to the fetched row data.

+	 * @param mixed row data fetched.

+	 * @param TActiveRecord object to be cached.

+	 * @return TActiveRecord cached object.

+	 */

+	public function addCachedInstance($data,$obj)

+	{

+		$key = $this->getObjectDataKey($data);

+		$this->registerClean($obj);

+		$this->_cachedObjects[$key]=$obj;

+		return $obj;

+	}

+

+	/**

+	 * @return string hash of the data.

+	 */

+	protected function getObjectDataKey($data)

+	{

+		return sprintf('%x',crc32(serialize($data)));

+	}

+

+	/**

+	 * Ensure that object is not null.

+	 */

+	protected function assertNotNull($obj)

+	{

+		if(is_null($obj))

+			throw new TActiveRecordException('ar_object_must_not_be_null');

+	}

+

+	/**

+	 * Register the object for deletion, when the object invokes its delete() method

+	 * the corresponding row in the database is deleted.

+	 * @param TActiveRecord existing active record.

+	 * @throws TActiveRecordException if object is null.

+	 */

+	public function registerRemoved($obj)

+	{

+		$this->assertNotNull($obj);

+		$found=false;

+		foreach($this->_cleanObjects as $i=>$cache)

+		{

+			if($cache[0]===$obj)

+			{

+				unset($this->_cleanObjects[$i]);

+				$found=true;

+			}

+		}

+		if(!$found)

+			throw new TActiveRecordException('ar_object_must_be_retrieved_before_delete');

+		if(!$this->_removedObjects->contains($obj))

+			$this->_removedObjects->add($obj);

+	}

+

+	/**

+	 * Register a clean object attached to a specific data that was used to

+	 * populate the object. This acts as an object cache.

+	 * @param TActiveRecord new clean object.

+	 */

+	public function registerClean($obj)

+	{

+		$this->removeCleanOrDirty($obj);

+		if($this->getIsRemovedObject($obj))

+			throw new TActiveRecordException('ar_object_marked_for_removal');

+		$this->_cleanObjects[] = array($obj, clone($obj));

+	}

+

+	/**

+	 * Remove the object from dirty state.

+	 * @param TActiveRecord object to remove.

+	 */

+	protected function removeDirty($obj)

+	{

+		$this->assertNotNull($obj);

+		foreach($this->_cleanObjects as $i=>$cache)

+			if($cache[0]===$obj && $obj != $cache[1])

+				unset($this->_cleanObjects[$i]);

+	}

+

+	/**

+	 * Remove object from clean state.

+	 * @param TActiveRecord object to remove.

+	 */

+	protected function removeClean($obj)

+	{

+		$this->assertNotNull($obj);

+		foreach($this->_cleanObjects as $i=>$cache)

+			if($cache[0]===$obj && $obj == $cache[1])

+				unset($this->_cleanObjects[$i]);

+	}

+

+	/**

+	 * Remove object from dirty and clean state.

+	 * @param TActiveRecord object to remove.

+	 */

+	protected function removeCleanOrDirty($obj)

+	{

+		$this->assertNotNull($obj);

+		foreach($this->_cleanObjects as $i=>$cache)

+			if($cache[0]===$obj)

+				unset($this->_cleanObjects[$i]);

+	}

+

+	/**

+	 * Remove object from removed state.

+	 * @param TActiveRecord object to remove.

+	 */

+	protected function removeRemovedObject($obj)

+	{

+		$this->_removedObjects->remove($obj);

+	}

+

+	/**

+	 * Test whether an object is dirty or has been modified.

+	 * @param TActiveRecord object to test.

+	 * @return boolean true if the object is dirty, false otherwise.

+	 */

+	public function getIsDirtyObject($obj)

+	{

+		foreach($this->_cleanObjects as $cache)

+			if($cache[0] === $obj)

+				return $obj != $cache[1];

+		return false;

+	}

+

+	/**

+	 * Test whether an object is in the clean state.

+	 * @param TActiveRecord object to test.

+	 * @return boolean true if object is clean, false otherwise.

+	 */

+	public function getIsCleanObject($obj)

+	{

+		foreach($this->_cleanObjects as $cache)

+			if($cache[0] === $obj)

+				return $obj == $cache[1];

+		return false;

+	}

+

+	/**

+	 * Test whether an object is a new instance.

+	 * @param TActiveRecord object to test.

+	 * @return boolean true if object is newly created, false otherwise.

+	 */

+	public function getIsNewObject($obj)

+	{

+		if($this->getIsRemovedObject($obj)) return false;

+		foreach($this->_cleanObjects as $cache)

+			if($cache[0] === $obj)

+				return false;

+		return true;

+	}

+

+	/**

+	 * Test whether an object is marked for deletion.

+	 * @param TActiveRecord object to test.

+	 * @return boolean true if object is marked for deletion, false otherwise.

+	 */

+	public function getIsRemovedObject($obj)

+	{

+		return $this->_removedObjects->contains($obj);

+	}

+

+	/**

+	 * Commit the object to database:

+	 *   * a new record is inserted if the object is new, object becomes clean.

+	 *   * the record is updated if the object is dirty, object becomes clean.

+	 *   * the record is deleted if the object is marked for removal.

+	 *

+	 * @param TActiveRecord record object.

+	 * @param TActiveRecordGateway database gateway

+	 * @return boolean true if commit was successful, false otherwise.

+	 */

+	public function commit($record,$gateway)

+	{

+		$rowsAffected=0;

+

+		if($this->getIsRemovedObject($record))

+		{

+			$rowsAffected = $gateway->delete($record);

+			if($rowsAffected===1)

+				$this->removeRemovedObject($record);

+		}

+		else

+		{

+			if($this->getIsDirtyObject($record))

+				$rowsAffected = $gateway->update($record);

+			else if($this->getIsNewObject($record))

+				$rowsAffected = $gateway->insert($record);

+

+			if($rowsAffected===1)

+				$this->registerClean($record);

+		}

+		return $rowsAffected===1;

+	}

+}

+
+?>
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