/*
    * Copyright 2008 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.facade.assetapi.asset;
  
  import java.util.AbstractMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Set;
  
  import com.fatwire.assetapi.def.AttributeDef;
  
  /**
   * This class adapts an <tt>TemplateAsset</tt> into a <tt>Map</tt>. The Map is
   * convenient in expression languages like JSP EL.
   * <p/>
   * This class uses lazy-loading, so if used in a View layer, it might open
   * connections to the database.
   * <p/>
   * In case of naming conflicts with flex attribute names and meta attribute
   * names the meta attributes take precedent.
   * 
   * 
   * @author Dolf.Dijkstra
   * @since Nov 23,2009
   * 
   */
  public class AssetMapAdapter extends AbstractMap<String, Object> implements Map<String, Object> {
  
      private final TemplateAsset delegate;
      private final Set<String> metaAttributes = new HashSet<String>();
  
      public AssetMapAdapter(TemplateAsset delegate) {
          super();
          this.delegate = delegate;
          // meta attributes are part of the assettype definition.
          for (AttributeDef d : delegate.getAssetTypeDef().getAttributeDefs()) {
              if (d.isMetaDataAttribute())
                  metaAttributes.add(d.getName());
          }
  
      }
  
      @Override
      public Set<java.util.Map.Entry<String, Object>> entrySet() {
          return entries;
      }
  
      private Set<java.util.Map.Entry<String, Object>> entries = new java.util.AbstractSet<java.util.Map.Entry<String, Object>>() {
  
          @Override
          public Iterator<java.util.Map.Entry<String, Object>> iterator() {
              final Iterator<String> names = delegate.getAttributeNames().iterator();
              return new Iterator<java.util.Map.Entry<String, Object>>() {
  
                  public boolean hasNext() {
                      return names.hasNext();
                  }
  
                  public java.util.Map.Entry<String, Object> next() {
                      final String name = names.next();
                      final Object value = delegate.getAttribute(name);
                      return new Entry<String, Object>() {
  
                          public String getKey() {
                              return name;
                          }
  
                          public Object getValue() {
                              return value;
                          }
  
                          public Object setValue(Object value) {
                              throw new UnsupportedOperationException(
                                      "Not allowed to set an asset attribute value, asset is immutable");
                          }
  
                      };
                  }
  
                  public void remove() {
                      throw new UnsupportedOperationException(
                              "Not allowed to remove an asset attribute, asset is immutable");
  
                  }
 
             };
         }
 
         @Override
         public int size() {
             return delegate.getAttributeNames().size();
         }
     };
 }