Source for file TopicMapSystemFactory.abstract.php

<?php
/**
 * @package org.phptmapi.core
*/
require_once('FactoryConfigurationException.exception.php');
/**
* abstract class TopicMapSystemFactory: This factory class provides access to a topic map system. A new TopicMapSystemInterface instance is created by invoking the newTopicMapSystem() method. Configuration properties for the new TopicMapSystemInterface instance can be set by calling the setFeature() and/or setProperty() methods prior to invoking newTopicMapSystem().
*
* @author Johannes Schmidt - t8d <kontakt@t8d.de>
*/
abstract class TopicMapSystemFactory{
    /**
    * Constructor
    * @access public
    * @return void 
    */
    abstract function __construct();
    
    /**
    * newInstance: This static method creates a new factory instance.
    * @access public
    * @return object TopicMapSystemFactory 
    * @throws FactoryConfigurationException
    */
    public static function newInstance(){
        try{
            $class = self::getClassFromFile();
            if($class instanceof TopicMapSystemFactory){
                $instance = $class->newInstance();
                return $instance;
            }
                else throw new FactoryConfigurationException('Exception in '.__method__.': Cannot instantiate an implementation of TopicMapSystemFactory!');
        }
            catch(FactoryConfigurationException $e){
                $exception = $e->getCause();
                echo $exception->getMessage();
            }
    }
    
    /**
    * newTopicMapSystem: Creates a new TopicMapSystemInterface instance using the currently configured factory parameters.
    * @access public
    * @return object TopicMapSystemInterface 
    * @throws TMAPIException if a topic map system cannot be created which satisfies the requested configuration.
    *  <code>
    *      public function newTopicMapSystem(){
    *         throw new TMAPIException('Exception in '.__method__);
    *      }
    *  </code>
    */
    abstract function newTopicMapSystem();
    
    /**
    * setFeature: Sets a particular feature in the underlying implementation of TopicMapSystemInterface. A list of the core features can be found at  http://tmapi.org/features/.
    * @param string $featureName The name of the feature to be set.
    * @param boolean $value True to enable the feature, false to disable it.
    * @access public
    * @return void 
    * @throws FeatureNotRecognizedException if the underlying implementation does not recognize the named feature.
    * @throws FeatureNotSupportedException if the underlying implementation recognizes the named feature but does not support enabling or disabling it (as specified by the value parameter).
    *  <code>
    *      public function setFeature($featureName, $value){
    *         throw new FeatureNotRecognizedException('Exception in '.__method__);
    *         throw new FeatureNotSupportedException('Exception in '.__method__);
    *      }
    *  </code>
    */
    abstract function setFeature($featureName, $value);
    
    /**
    * Returns the particular feature requested for in the underlying implementation of TopicMapSystemInterface.
    * @param string $featureName The name of the feature to check.
    * @access public
    * @return boolean true if the named feature is enabled for TopicMapSystemInterface instances created by this factory; false if the named feature is disabled for TopicMapSystemInterface instances created by this factory.
    * @throws FeatureNotRecognizedException if the underlying implementation does not recognize the named feature.
    *  <code>
    *      public function getFeature($featureName){
    *         throw new FeatureNotRecognizedException('Exception in '.__method__);
    *      }
    *  </code>
    */
    abstract function getFeature($featureName);
    
    /**
    * Returns if the particular feature is supported by the TopicMapSystemInterface. Opposite to getFeature() this method returns if the requested feature is generally available/supported by the underlying TopicMapSystemInterface and does not return the state (enabled/disabled) of the feature.
    * @param string $featureName The name of the feature to check.
    * @access public
    * @return boolean true if the requested feature is supported, otherwise false.
    */
    abstract function hasFeature($featureName);
    
    /**
    * Sets the properties in the underlying implementation of TopicMapSystemInterface.
    * @param array $props The properties to be used to initialise the system.
    * @access public
    * @return void 
    * @see setProperty()
    */
    abstract function setProperties($props);
    
    /**
    * Sets a property in the underlying implementation of TopicMapSystemInterface. A list of the core properties defined by TMAPI can be found at  http://tmapi.org/properties/. An implementation is free to support properties other than the core ones.
    * @param string $propertyName The name of the property to be set
    * @param string $value The value to be set of this property or null to remove the property from the current factory configuration.
    * @access public
    * @return void 
    */
    abstract function setProperty($propertyName, $value);
    
    /**
    * Gets the value of a property in the underlying implementation of TopicMapSystemInterface.
    * A list of the core properties defined by TMAPI can be found at  http://tmapi.org/properties/. An implementation is free to support properties other than the core ones.
    * @param string $propertyName The name of the property to retrieve.
    * @access public
    * @return string The value set for this property or null if no value is currently set for the property.
    */
    abstract function getProperty($propertyName);
    
    /**
    * getClassFromFile: Returns the TopicMapSystemFactory implementation using the discovery file.
    * @access private
    * @return object TopicMapSystemFactory 
    * @throws FactoryConfigurationException
    */
    private static function getClassFromFile(){
        try{
            $dir = '../META/factory/';
            if($dh = opendir($dir)){
                while(($tempfile = readdir($dh)) !== false) {
                    $file = $tempfile;
                }
                closedir($dh);
                if($pathToClass = file_get_contents($dir.$file)){
                    require_once $pathToClass;
                    $class = $file;
                    $class = new $class;
                    return $class;
                }
                    else throw new FactoryConfigurationException('Exception in '.__method__.': Cannot read discovery file for the implementation of TopicMapSystemFactory!');
            }
                else throw new FactoryConfigurationException('Exception in '.__method__.': Cannot open directory that includes discovery file for the implementation of TopicMapSystemFactory!');
        }
            catch(FactoryConfigurationException $e){
                $exception = $e->getCause();
                echo $exception->getMessage();
            }
    }
}
?>