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package com.hfg.util.collection;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

//------------------------------------------------------------------------------
/**
 * HashMap that keeps a dirty flag.
 * @author J. Alex Taylor, hairyfatguy.com
 */
//------------------------------------------------------------------------------
// com.hfg Library
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// J. Alex Taylor, President, Founder, CEO, COO, CFO, OOPS hairyfatguy.com
// [email protected]
//------------------------------------------------------------------------------

public class DirtyMap extends HashMap
{
   private boolean mIsDirty;
   private Set  mDirtyKeySet;

   //##########################################################################
   // CONSTRUCTORS
   //##########################################################################

   //--------------------------------------------------------------------------
   public DirtyMap()
   {
      super();
   }

   //--------------------------------------------------------------------------
   public DirtyMap(int inInitialCapacity)
   {
      super(inInitialCapacity);
   }

   //--------------------------------------------------------------------------
   public DirtyMap(int inInitialCapacity, float inLoadFactor)
   {
      super(inInitialCapacity, inLoadFactor);
   }

   //--------------------------------------------------------------------------
   public DirtyMap(Map inMap)
   {
      super(inMap);
   }

   //##########################################################################
   // PUBLIC METHODS
   //##########################################################################

   //--------------------------------------------------------------------------
   public void bless()
   {
      mIsDirty = false;
      mDirtyKeySet = null;
   }

   //--------------------------------------------------------------------------
   public boolean isDirty()
   {
      return mIsDirty;
   }

   //--------------------------------------------------------------------------
   public Set dirtyKeySet()
   {
      return CollectionUtil.hasValues(mDirtyKeySet) ? mDirtyKeySet : null;
   }

   //--------------------------------------------------------------------------
   @Override
   public void clear()
   {
      if (size() > 0)
      {
         mIsDirty = true;
         super.clear();

         mDirtyKeySet = null;
      }
   }

   //--------------------------------------------------------------------------
   @Override
   public V put(K inKey, V inValue)
   {
      if (containsKey(inKey))
      {
         V currentValue = get(inKey);

         boolean changed;
         if (null == inValue)
         {
            changed = (currentValue != null);
         }
         else if (null == currentValue)
         {
            changed = true;
         }
         else
         {
            changed = !currentValue.equals(inValue);
         }

         if (changed)
         {
            if (null == mDirtyKeySet)
            {
               mDirtyKeySet = new HashSet<>(size());
            }

            mDirtyKeySet.add(inKey);

            if (!isDirty())
            {
               mIsDirty = changed;
            }
         }
      }
      else
      {
         // New key
         if (null == mDirtyKeySet)
         {
            mDirtyKeySet = new HashSet<>(size());
         }

         mDirtyKeySet.add(inKey);

         mIsDirty = true;
      }

      return super.put(inKey, inValue);
   }

   //--------------------------------------------------------------------------
   @Override
   public void putAll(Map m)
   {
      for (K key : m.keySet())
      {
         put(key, m.get(key));
      }
   }

   //--------------------------------------------------------------------------
   @Override
   public V remove(Object inKey)
   {
      boolean containsKey = containsKey(inKey);
      if (mDirtyKeySet != null
          && containsKey)
      {
         mDirtyKeySet.remove(inKey);
      }

      if (! isDirty()
          && containsKey)
      {
         mIsDirty = true;
      }

      return super.remove(inKey);
   }

}