Add JLanguageStemmer. Add unit tests for JLanguage.

libraries/joomla/language/stemmer.php

@@ -0,0 +1,78 @@
+<?php
+/**
+ * @package     Joomla.Platform
+ * @subpackage  Language
+ *
+ * @copyright   Copyright (C) 2005 - 2012 Open Source Matters, Inc. All rights reserved.
+ * @license     GNU General Public License version 2 or later; see LICENSE
+ */
+
+defined('JPATH_PLATFORM') or die;
+
+/**
+ * Stemmer base class.
+ *
+ * @package     Joomla.Platform
+ * @subpackage  Language
+ * @since       12.1
+ */
+abstract class JLanguageStemmer
+{
+	/**
+	 * An internal cache of stemmed tokens.
+	 *
+	 * @var    array
+	 * @since  12.1
+	 */
+	protected $cache = array();
+
+	/**
+	 * @var    array  JLanguageStemmer instances.
+	 * @since  12.1
+	 */
+	protected static $instances = array();
+
+	/**
+	 * Method to get a stemmer, creating it if necessary.
+	 *
+	 * @param   string  $adapter  The type of stemmer to load.
+	 *
+	 * @return  JLanguageStemmer  A JLanguageStemmer instance.
+	 *
+	 * @since   12.1
+	 * @throws  RuntimeException on invalid stemmer.
+	 */
+	public static function getInstance($adapter)
+	{
+		// Only create one stemmer for each adapter.
+		if (isset(self::$instances[$adapter]))
+		{
+			return self::$instances[$adapter];
+		}
+
+		// Setup the adapter for the stemmer.
+		$class = 'JLanguageStemmer' . ucfirst(trim($adapter));
+
+		// Check if a stemmer exists for the adapter.
+		if (!class_exists($class))
+		{
+			// Throw invalid adapter exception.
+			throw new RuntimeException(JText::sprintf('JLIB_STEMMER_INVALID_STEMMER', $adapter));
+		}
+
+		self::$instances[$adapter] = new $class;
+		return self::$instances[$adapter];
+	}
+
+	/**
+	 * Method to stem a token and return the root.
+	 *
+	 * @param   string  $token  The token to stem.
+	 * @param   string  $lang   The language of the token.
+	 *
+	 * @return  string  The root token.
+	 *
+	 * @since   12.1
+	 */
+	abstract public function stem($token, $lang);
+}