/*
    * Copyright 2005-2007 The Kuali Foundation
    * 
    * 
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
   * 
   * 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 org.kuali.rice.core.util;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.Modifier;
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * Have constants class extend this class to expose them to JSTL as a HashMap.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class JSTLConstants extends HashMap {
  
      private static final long serialVersionUID = 6701136401021219281L;
      private boolean initialised = false;
  
      public JSTLConstants() {
      	publishFields(this, this.getClass());
          initialised = true;
      }
      
      public JSTLConstants(Class constantsClass) {
          publishFields(this, constantsClass);
          initialised = true;
      }
  
      /**
       * Publishes all of the static, final, non-private fields of the given Class as entries in the given HashMap instance
       * 
       * @param constantMap
       * @param c
       */
      protected void publishFields(Map constantMap, Class c) {
          Field[] fields = c.getDeclaredFields();
          for (Field field : fields) {
              int modifier = field.getModifiers();
  
              // publish values of static, final, non-private members
              if (Modifier.isStatic(modifier) && Modifier.isFinal(modifier) && !Modifier.isPrivate(modifier)) {
                  try {
                      String fieldName = field.getName();
  
                      constantMap.put(fieldName, field.get(null));
                  } catch (IllegalAccessException e) {}
              }
          }
  
          // publish values of appropriate fields of member classes
          publishMemberClassFields(constantMap, c);
      }
  
      /**
       * Publishes all of the static, final, non-private fields of the non-anonymous member classes of the given Class as entries in
       * the given HashMap instance
       * 
       * @param constantMap
       * @param c
       */
      protected void publishMemberClassFields(Map constantMap, Class c) {
          Class[] memberClasses = c.getClasses();
  
          for (Class memberClass : memberClasses) {
              if (!memberClass.isAnonymousClass()) {
                  String memberPrefix = memberClass.getSimpleName();
  
                  Map subclassMap = new HashMap();
                  publishFields(subclassMap, memberClass);
                  constantMap.put(memberClass.getSimpleName(), subclassMap);
              }
          }
      }
  
      public void clear() {
          if (!initialised)
              super.clear();
          else
              throw new UnsupportedOperationException("Cannot modify this map");
      }
  
      public Object put(Object key, Object value) {
          if (!initialised)
              return super.put(key, value);
         else
             throw new UnsupportedOperationException("Cannot modify this map");
     }
 
     public void putAll(Map m) {
         if (!initialised)
             super.putAll(m);
         else
             throw new UnsupportedOperationException("Cannot modify this map");
     }
 
     public Object remove(Object key) {
         if (!initialised)
             return super.remove(key);
         else
             throw new UnsupportedOperationException("Cannot modify this map");
     }
 }