/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.myfaces.util;
  
  import java.util.AbstractMap;
  import java.util.AbstractSet;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Enumeration;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  
  
  /**
   * Helper Map implementation for use with different Attribute Maps.
   * 
   * @author Anton Koinov (latest modification by $Author: lu4242 $)
   * @version $Revision: 982465 $ $Date: 2010-08-04 23:39:32 -0500 (Mié, 04 Ago 2010) $
   */
  public abstract class AbstractThreadSafeAttributeMap extends AbstractMap
  {
      private Set              _keySet;
      private Collection       _values;
      private Set              _entrySet;
  
      public void clear()
      {
          final List names = _list(getAttributeNames());
  
          for (Iterator it = names.iterator(); it.hasNext();)
          {
              removeAttribute((String) it.next());
          }
      }
  
      public boolean containsKey(Object key)
      {
          return getAttribute(key.toString()) != null;
      }
  
      public boolean containsValue(Object findValue)
      {
          if (findValue == null)
          {
              return false;
          }
  
          for (Enumeration e = getAttributeNames(); e.hasMoreElements();)
          {
              Object value = getAttribute((String) e.nextElement());
              if (findValue.equals(value))
              {
                  return true;
              }
          }
  
          return false;
      }
  
      public Set entrySet()
      {
          return (_entrySet != null) ? _entrySet : (_entrySet = new EntrySet());
      }
  
      public Object get(Object key)
      {
          return getAttribute(key.toString());
      }
  
      public boolean isEmpty()
      {
          return !getAttributeNames().hasMoreElements();
      }
  
      public Set keySet()
      {
          return (_keySet != null) ? _keySet : (_keySet = new KeySet());
      }
  
      public Object put(Object key, Object value)
     {
         String key_ = key.toString();
         Object retval = getAttribute(key_);
         setAttribute(key_, value);
         return retval;
     }
 
     public void putAll(Map t)
     {
         for (Iterator it = t.entrySet().iterator(); it.hasNext();)
         {
             Entry entry = (Entry) it.next();
             setAttribute(entry.getKey().toString(), entry.getValue());
         }
     }
 
     public Object remove(Object key)
     {
         String key_ = key.toString();
         Object retval = getAttribute(key_);
         removeAttribute(key_);
         return retval;
     }
 
     public int size()
     {
         int size = 0;
         for (Enumeration e = getAttributeNames(); e.hasMoreElements();)
         {
             size++;
             e.nextElement();
         }
         return size;
     }
 
     public Collection values()
     {
         return (_values != null) ? _values : (_values = new Values());
     }
     
     /**
      * Collections.list() from JDK 1.4
      */
     private ArrayList _list(Enumeration e) {
         ArrayList l = new ArrayList();
         while (e.hasMoreElements())
         {
             l.add(e.nextElement());
         }
         return l;
     }
     
 
     abstract protected Object getAttribute(String key);
 
     abstract protected void setAttribute(String key, Object value);
 
     abstract protected void removeAttribute(String key);
 
     abstract protected Enumeration getAttributeNames();
 
 
     private class KeySet extends AbstractSet
     {
         public Iterator iterator()
         {
             return new KeyIterator();
         }
 
         public boolean isEmpty()
         {
             return AbstractThreadSafeAttributeMap.this.isEmpty();
         }
 
         public int size()
         {
             return AbstractThreadSafeAttributeMap.this.size();
         }
 
         public boolean contains(Object o)
         {
             return AbstractThreadSafeAttributeMap.this.containsKey(o);
         }
 
         public boolean remove(Object o)
         {
             return AbstractThreadSafeAttributeMap.this.remove(o) != null;
         }
 
         public void clear()
         {
             AbstractThreadSafeAttributeMap.this.clear();
         }
     }
 
     private class KeyIterator
         implements Iterator
     {
         // We use a copied version of the Enumeration from getAttributeNames()
         // here, because directly using it might cause a ConcurrentModificationException
         // when performing remove(). Note that we can do this since the Enumeration
         // from getAttributeNames() will contain exactly the attribute names from the time
         // getAttributeNames() was called and it will not be updated if attributes are 
         // removed or added.
         protected final Iterator _i = _list(getAttributeNames()).iterator();
         protected Object _currentKey;
 
         public void remove()
         {
             if (_currentKey == null)
             {
                 throw new NoSuchElementException(
                     "You must call next() at least once");
             }
             AbstractThreadSafeAttributeMap.this.remove(_currentKey);
         }
 
         public boolean hasNext()
         {
             return _i.hasNext();
         }
 
         public Object next()
         {
             return _currentKey = _i.next();
         }
     }
 
     private class Values extends KeySet
     {
         public Iterator iterator()
         {
             return new ValuesIterator();
         }
 
         public boolean contains(Object o)
         {
             return AbstractThreadSafeAttributeMap.this.containsValue(o);
         }
 
         public boolean remove(Object o)
         {
             if (o == null)
             {
                 return false;
             }
 
             for (Iterator it = iterator(); it.hasNext();)
             {
                 if (o.equals(it.next()))
                 {
                     it.remove();
                     return true;
                 }
             }
 
             return false;
         }
     }
 
     private class ValuesIterator extends KeyIterator
     {
         public Object next()
         {
             super.next();
             return AbstractThreadSafeAttributeMap.this.get(_currentKey);
         }
     }
 
     private class EntrySet extends KeySet
     {
         public Iterator iterator() {
             return new EntryIterator();
         }
 
         public boolean contains(Object o) {
             if (!(o instanceof Entry))
             {
                 return false;
             }
 
             Entry entry = (Entry) o;
             Object key = entry.getKey();
             Object value = entry.getValue();
             if (key == null || value == null)
             {
                 return false;
             }
 
             return value.equals(AbstractThreadSafeAttributeMap.this.get(key));
         }
 
         public boolean remove(Object o) {
             if (!(o instanceof Entry))
             {
                 return false;
             }
 
             Entry entry = (Entry) o;
             Object key = entry.getKey();
             Object value = entry.getValue();
             if (key == null || value == null
                 || !value.equals(AbstractThreadSafeAttributeMap.this.get(key)))
             {
                 return false;
             }
 
             return AbstractThreadSafeAttributeMap.this.remove(((Entry) o).getKey()) != null;
         }
     }
 
     /**
      * Not very efficient since it generates a new instance of <code>Entry</code>
      * for each element and still internaly uses the <code>KeyIterator</code>.
      * It is more efficient to use the <code>KeyIterator</code> directly.
      */
     private class EntryIterator extends KeyIterator
     {
         public Object next()
         {
             super.next();
             // Must create new Entry every time--value of the entry must stay
             // linked to the same attribute name
             return new EntrySetEntry(_currentKey);
         }
     }
 
     private class EntrySetEntry implements Entry
     {
         private final Object _currentKey;
 
         public EntrySetEntry(Object currentKey)
         {
             _currentKey = currentKey;
         }
 
         public Object getKey()
         {
             return _currentKey;
         }
 
         public Object getValue()
         {
             return AbstractThreadSafeAttributeMap.this.get(_currentKey);
         }
 
         public Object setValue(Object value)
         {
             return AbstractThreadSafeAttributeMap.this.put(_currentKey, value);
         }
 
         public int hashCode() {
             return _currentKey == null ? 0 : _currentKey.hashCode();
         }
 
         public boolean equals(Object obj) {
             if (!(obj instanceof EntrySetEntry))
                 return false;
             return _currentKey != null && _currentKey.equals(obj);
         }
     }
 }