package org.jboss.resteasy.specimpl;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.ws.rs.core.MultivaluedMap;

/**
 * Unmodifiable implementation of {@link javax.ws.rs.core.MultivaluedMap} interface
 *
 * @author <a href="mailto:mstefank@redhat.conm">Martin Stefanko</a>
 * @version $Revision: 1 $
 */
public class UnmodifiableMultivaluedMap<K, V> implements MultivaluedMap<K, V>
{

   private final MultivaluedMap<K, V> delegate;

   private volatile Set<java.util.Map.Entry<K, List<V>>> entrySet;

   public UnmodifiableMultivaluedMap(final MultivaluedMap<K, V> delegate)
   {
      this(delegate, true);
   }

   public UnmodifiableMultivaluedMap(final MultivaluedMap<K, V> delegate, final boolean eagerlyInitializeEntrySet)
   {
      this.delegate = delegate;
      if (eagerlyInitializeEntrySet) {
         this.entrySet = buildEntrySet();
      }
   }

   private Set<java.util.Map.Entry<K, List<V>>> buildEntrySet()
   {
      Set<java.util.Map.Entry<K, List<V>>> entrySetDelegator = delegate.entrySet();
      Set<java.util.Map.Entry<K, List<V>>> entrySetToReturn = new HashSet<>();
      for (final java.util.Map.Entry<K, List<V>> entry : entrySetDelegator)
      {
         entrySetToReturn.add(new Entry<K, List<V>>()
         {

            @Override
            public K getKey()
            {
               return entry.getKey();
            }

            @Override
            public List<V> getValue()
            {
               List<V> value = entry.getValue();
               return value == null ? null : Collections.unmodifiableList(value);
            }

            @Override
            public List<V> setValue(List<V> value)
            {
               throw new UnsupportedOperationException();
            }
         });
      }
      return Collections.unmodifiableSet(entrySetToReturn);
   }

   @Override
   public void putSingle(K k, V v)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public void add(K k, V v)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public V getFirst(K key)
   {
      return delegate.getFirst(key);
   }

   @SuppressWarnings(value = "unchecked")
   @Override
   public void addAll(K k, V... vs)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public void addAll(K k, List<V> list)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public void addFirst(K k, V v)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public boolean equalsIgnoreValueOrder(MultivaluedMap<K, V> omap)
   {
      return delegate.equalsIgnoreValueOrder(omap);
   }

   @Override
   public void clear()
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public Set<Entry<K, List<V>>> entrySet()
   {
      if (this.entrySet == null) {
         this.entrySet = buildEntrySet();
      }
      return this.entrySet;
   }

   @Override
   public List<V> get(Object key)
   {
      List<V> list = delegate.get(key);
      return list == null ? null : Collections.unmodifiableList(list);
   }

   @Override
   public Set<K> keySet()
   {
      return Collections.unmodifiableSet(delegate.keySet());
   }

   @Override
   public List<V> put(K key, List<V> value)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public void putAll(Map<? extends K, ? extends List<V>> m)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public List<V> remove(Object key)
   {
      throw new UnsupportedOperationException();
   }

   @Override
   public Collection<List<V>> values()
   {
      return Collections.unmodifiableCollection(delegate.values());
   }

   @Override
   public boolean containsKey(Object o)
   {
      return delegate.containsKey(o);
   }

   @Override
   public boolean containsValue(Object o)
   {
      return delegate.containsValue(o);
   }

   @Override
   public int size()
   {
      return delegate.size();
   }

   @Override
   public boolean isEmpty()
   {
      return delegate.isEmpty();
   }

   @Override
   public String toString()
   {
      return delegate.toString();
   }
}
