class.ObjectFactory.php

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<?php
/**
 * wCMF - wemove Content Management Framework
 * Copyright (C) 2005-2014 wemove digital solutions GmbH
 *
 * Licensed under the terms of any of the following licenses 
 * at your choice:
 *
 * - GNU Lesser General Public License (LGPL)
 *   http://www.gnu.org/licenses/lgpl.html
 * - Eclipse Public License (EPL)
 *   http://www.eclipse.org/org/documents/epl-v10.php
 *
 * See the license.txt file distributed with this work for 
 * additional information.
 *
 * $Id: class.ObjectFactory.php 1462 2014-02-04 23:52:27Z iherwig $
 */
require_once(BASE."wcmf/lib/util/class.Message.php");
require_once(BASE."wcmf/lib/util/class.InifileParser.php");

/**
 * @class ObjectFactory
 * @ingroup Util
 * @brief ObjectFactory loads class definitions and instantiates classes.
 *
 * @author      ingo herwig <ingo@wemove.com>
 */
class ObjectFactory
{
  var $_errorMsg = '';

  /**
   * Get last error message.
   * @return The error string
   */
  function getErrorMsg()
  {
    return $this->_errorMsg;
  }
  /**
   * Returns an instance of the class.
   * @return A reference to the only instance of the Singleton object
   */  
  function &getInstance()
  {
    static $instance = null;

    if (!isset($instance))
      $instance = new ObjectFactory();

    return $instance;
  }
  /**
   * Get the class file for a given class name.
   * This method looks up the class definition from 'classmapping' section. 
   * @param className The name of the class.
   * @return Classfile on success, False else / error string provided by getErrorMsg()
   */  
  function getClassfileFromConfig($className)
  {
    // find class file
    $parser = &InifileParser::getInstance();
    if (($classFile = $parser->getValue($className, 'classmapping', false)) === false)
    {
      $this->_errorMsg = $parser->getErrorMsg();
      return false;
    }
    return $classFile;
  }
  /**
   * Load a class definition from a configuration entry.
   * This method looks up the class name as value of $classEntry in $section of the main
   * configuration file and takes class definition from 'classmapping' section. 
   * With this information it includes the desired class definition.
   * @param section The name of the section, where the class is defined.
   * @param classEntry The name of the key in the section, where the class is defined.
   * @return Classname on success, False else / error string provided by getErrorMsg()
   */  
  function loadClassDefinitionFromConfig($section, $classEntry)
  {
    // find class name
    $parser = &InifileParser::getInstance();
    if (($className = $parser->getValue($classEntry, $section)) === false)
    {
      $this->_errorMsg = $parser->getErrorMsg();
      return false;
    }
    // find class file
    if (($classFile = $this->getClassfileFromConfig($className)) === false)
      return false;

    // include class definition
    if (file_exists(BASE.$classFile))
    {
      require_once(BASE.$classFile);
      return $className;
    }
    else
    {
      $this->_errorMsg = "Classfile ".$classFile." not found.";
      return false;
    }
  }
  /**
   * Create an object from a configuration entry.
   * This method looks up the class name as value of $classEntry in $section of the main
   * configuration file and takes - if given - constructor parameters from the 'initparams' 
   * section and class definition from 'classmapping' section. With this information it
   * constructs the desired object.
   * @param section The name of the section, where the class is defined.
   * @param classEntry The name of the key in the section, where the class is defined.
   * @return A reference to an instance of the class, null if failed (error string provided by getErrorMsg()).
   */  
  function &createInstanceFromConfig($section, $classEntry)
  {
    $obj = null;

    // load class definition
    if (($className = $this->loadClassDefinitionFromConfig($section, $classEntry)) !== false)
    {
      // find init parameters
      $initParams = null;
      $parser = &InifileParser::getInstance();
      if (($initSection = $parser->getValue($className, 'initparams')) !== false)
        if (($initParams = $parser->getSection($initSection)) === false)
          $initParams = null;
  
      if ($initParams != null)
        $obj = new $className($initParams);
      else if (class_exists($className))
        $obj = new $className;
      else
        $this->_errorMsg = "Class ".$className." is not found defined.";
    }
    return $obj;
  }
}
?>