/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - Redistributions in binary form must reproduce the above copyright

  *     notice, this list of conditions and the following disclaimer in

  *     the documentation and/or other materials provided with the

  *     distribution.

  *

  *   - Neither the name of Pebble nor the names of its contributors may

  *     be used to endorse or promote products derived from this software

  *     without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

  * POSSIBILITY OF SUCH DAMAGE.

  */

 package net.sourceforge.pebble.web.action;

 import org.apache.commons.io.IOUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.springframework.beans.BeansException;

 import org.springframework.beans.factory.config.AutowireCapableBeanFactory;

 import org.springframework.context.ApplicationContext;

 import org.springframework.context.ApplicationContextAware;

 import javax.annotation.PostConstruct;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.util.Enumeration;

 import java.util.HashMap;

 import java.util.Map;

 import java.util.Properties;

 /**

  * A factory class from which to look up and retrieve an instance

  * of an Action class to process a specific request.

  *

  * @author    Simon Brown

  */

 public class DefaultActionFactory implements ActionFactory, ApplicationContextAware {

   /** the log used by this class */

   private static Log log = LogFactory.getLog(DefaultActionFactory.class);

   /** the collection of actions that we know about */

   private final Map<String, String> actions = new HashMap<String, String>();

   /** the name of the action mapping file */

   private String actionMappingFileName;

   /** the ApplicationContext to instantiate actions with */

   private AutowireCapableBeanFactory beanFactory;

   /**

    * Initialises this component, reading in and creating the map

    * of action names to action classes.

    *

    * @throws IOException If an error occurs looking up all the actions

    */

   @PostConstruct

   public void init() throws IOException {

     // Load all resources by the given name, allows for plugins to provide their own actions

     for (Enumeration<URL> e = getClass().getClassLoader().getResources(actionMappingFileName); e.hasMoreElements();) {

       URL url = e.nextElement();

       // load the properties file containing the name -> class name mapping

       InputStream in = null;

       try {

         in = url.openStream();

         Properties props = new Properties();

         props.load(in);

         actions.putAll((Map) props);

       } catch (IOException ioe) {

         log.error("Error reading actions for class: " + url, ioe);

       } finally {

         IOUtils.closeQuietly(in);

       }

     }

   }

   /**

    * Given the name/type of request, this method returns the Action

    * instance appropriate to process the request.

    *

    * @param name    the name (type) of the request

    * @return  an instance of Action (could be null if no mapping has been defined)

    */

   public Action getAction(String name) throws ActionNotFoundException {

     try {

       // instantiate the appropriate class to handle the request

       if (actions.containsKey(name)) {

         Class<?> c = getClass().getClassLoader().loadClass((String)actions.get(name));

         Class<? extends Action> actionClass = c.asSubclass(Action.class);

         return (Action) beanFactory.createBean(actionClass, AutowireCapableBeanFactory.AUTOWIRE_NO, false);

       } else {

         throw new ActionNotFoundException("An action called " + name + " could not be found");

       }

     } catch (ClassNotFoundException cnfe) {

       log.error(cnfe.getMessage(), cnfe);

       throw new ActionNotFoundException("An action called " + name + " could not be loaded", cnfe);

     } catch (BeansException be) {

       log.error(be.getMessage(), be);

       throw new ActionNotFoundException("An action called " + name + " could not be instantiated", be);

     }

   }

   public void setActionMappingFileName(String actionMappingFileName) {

     this.actionMappingFileName = actionMappingFileName;

   }

   public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

     this.beanFactory = applicationContext.getAutowireCapableBeanFactory();

   }

 }