/*
    * Copyright 2011 FatWire Corporation. All Rights Reserved.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *    http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.fatwire.gst.foundation.controller.action.support;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  
  import COM.FutureTense.Interfaces.ICS;
  
  import com.fatwire.gst.foundation.controller.action.Action;
  import com.fatwire.gst.foundation.controller.action.ActionLocator;
  import com.fatwire.gst.foundation.controller.action.Injector;
  import com.fatwire.gst.foundation.facade.logging.LogUtil;
  
  /**
   * ActionLocator that loads actions based on a naming convention; if the action name is prefixed with <tt>class:</tt>
   * and the rest of the action name is a java class that implements the Action interface , an Action from this class will be created.
   
   * 
   * @author Dolf Dijkstra
   *
   */
  public class ClassActionLocator extends AbstractActionLocator {
      private static final Log LOG = LogUtil.getLog(ClassActionLocator.class);
      private static final String CLASS_PREFIX = "class:";
  
      public ClassActionLocator(ActionLocator fallbackActionLocator, Injector injector) {
          super(fallbackActionLocator, injector);
  
      }
  
      public ClassActionLocator() {
          super();
      }
  
      @Override
      protected Action doFindAction(ICS ics, String name) {
          if (StringUtils.startsWith(name, CLASS_PREFIX)) {
              String c = StringUtils.trim(StringUtils.substringAfter(name, CLASS_PREFIX));
              if (StringUtils.isEmpty(c)) {
                  LOG.warn("Passed in classname with the " + CLASS_PREFIX + " is null or empty.");
              } else {
                  try {
                      Class<?> clazz = Thread.currentThread().getContextClassLoader().loadClass(c);
                      if (Action.class.isAssignableFrom(clazz)) {
                          LOG.debug("Creating Action for class " + clazz);
                          Action action = (Action) clazz.newInstance();
                          return action;
                      } else {
                          throw new RuntimeException("Class " + c + " is not an Action.");
                      }
  
                  } catch (ClassNotFoundException e) {
                      throw new RuntimeException("Class " + c + " cannot be found.", e);
                  } catch (InstantiationException e) {
                      throw new RuntimeException("Class " + c + " " + e.getMessage(), e);
                  } catch (IllegalAccessException e) {
                      throw new RuntimeException("Class " + c + " " + e.getMessage(), e);
                  }
              }
  
          }
          return null;
      }
  
  }