/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2009-2010 Sun Microsystems, Inc.
 */

package com.sun.opends.sdk.util;



import java.util.*;



/**
 * Additional {@code Collection} based utility methods.
 */
public final class Collections2
{
  private static class TransformedCollection<M, N, P, C extends Collection<M>>
      extends AbstractCollection<N> implements Collection<N>
  {

    protected final C collection;

    protected final Function<? super M, ? extends N, P> funcMtoN;

    protected final Function<? super N, ? extends M, P> funcNtoM;

    protected final P p;



    protected TransformedCollection(final C collection,
        final Function<? super M, ? extends N, P> funcMtoN,
        final Function<? super N, ? extends M, P> funcNtoM, final P p)
    {
      this.collection = collection;
      this.funcMtoN = funcMtoN;
      this.funcNtoM = funcNtoM;
      this.p = p;
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public boolean add(final N e)
    {
      return collection.add(funcNtoM.apply(e, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public void clear()
    {
      collection.clear();
    }



    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public boolean contains(final Object o)
    {
      final N tmp = (N) o;
      return collection.contains(funcNtoM.apply(tmp, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isEmpty()
    {
      return collection.isEmpty();
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public Iterator<N> iterator()
    {
      return Iterators.transformedIterator(collection.iterator(), funcMtoN, p);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public boolean remove(final Object o)
    {
      final N tmp = (N) o;
      return collection.remove(funcNtoM.apply(tmp, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public int size()
    {
      return collection.size();
    }

  }



  private static final class TransformedList<M, N, P> extends
      TransformedCollection<M, N, P, List<M>> implements List<N>
  {

    private TransformedList(final List<M> list,
        final Function<? super M, ? extends N, P> funcMtoN,
        final Function<? super N, ? extends M, P> funcNtoM, final P p)
    {
      super(list, funcMtoN, funcNtoM, p);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public void add(final int index, final N element)
    {
      collection.add(index, funcNtoM.apply(element, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public boolean addAll(final int index, final Collection<? extends N> c)
    {
      // We cannot transform c here due to type-safety.
      boolean result = false;
      for (final N e : c)
      {
        result |= add(e);
      }
      return result;
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public N get(final int index)
    {
      return funcMtoN.apply(collection.get(index), p);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public int indexOf(final Object o)
    {
      final N tmp = (N) o;
      return collection.indexOf(funcNtoM.apply(tmp, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public int lastIndexOf(final Object o)
    {
      final N tmp = (N) o;
      return collection.lastIndexOf(funcNtoM.apply(tmp, p));
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public ListIterator<N> listIterator()
    {
      return listIterator(0);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public ListIterator<N> listIterator(final int index)
    {
      final ListIterator<M> iterator = collection.listIterator(index);
      return new ListIterator<N>()
      {

        @Override
        public void add(final N e)
        {
          iterator.add(funcNtoM.apply(e, p));
        }



        @Override
        public boolean hasNext()
        {
          return iterator.hasNext();
        }



        @Override
        public boolean hasPrevious()
        {
          return iterator.hasPrevious();
        }



        @Override
        public N next()
        {
          return funcMtoN.apply(iterator.next(), p);
        }



        @Override
        public int nextIndex()
        {
          return iterator.nextIndex();
        }



        @Override
        public N previous()
        {
          return funcMtoN.apply(iterator.previous(), p);
        }



        @Override
        public int previousIndex()
        {
          return iterator.previousIndex();
        }



        @Override
        public void remove()
        {
          iterator.remove();
        }



        @Override
        public void set(final N e)
        {
          iterator.set(funcNtoM.apply(e, p));
        }

      };
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public N remove(final int index)
    {
      return funcMtoN.apply(collection.remove(index), p);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public N set(final int index, final N element)
    {
      final M result = collection.set(index, funcNtoM.apply(element, p));
      return funcMtoN.apply(result, p);
    }



    /**
     * {@inheritDoc}
     */
    @Override
    public List<N> subList(final int fromIndex, final int toIndex)
    {
      final List<M> subList = collection.subList(fromIndex, toIndex);
      return new TransformedList<M, N, P>(subList, funcMtoN, funcNtoM, p);
    }

  }



  /**
   * Returns a view of {@code collection} whose values have been mapped to
   * elements of type {@code N} using {@code funcMtoN}. The returned collection
   * supports all operations.
   *
   * @param <M>
   *          The type of elements contained in {@code collection}.
   * @param <N>
   *          The type of elements contained in the returned collection.
   * @param <P>
   *          The type of the additional parameter to the function's
   *          {@code apply} method. Use {@link java.lang.Void} for functions
   *          that do not need an additional parameter.
   * @param collection
   *          The collection to be transformed.
   * @param funcMtoN
   *          A function which maps values of type {@code M} to values of type
   *          {@code N}. This function will be used when retrieving values from
   *          {@code collection}.
   * @param funcNtoM
   *          A function which maps values of type {@code N} to values of type
   *          {@code M}. This function will be used when performing queries and
   *          adding values to {@code collection} .
   * @param p
   *          A predicate specified parameter.
   * @return A view of {@code collection} whose values have been mapped to
   *         elements of type {@code N} using {@code funcMtoN}.
   */
  public static <M, N, P> Collection<N> transformedCollection(
      final Collection<M> collection,
      final Function<? super M, ? extends N, P> funcMtoN,
      final Function<? super N, ? extends M, P> funcNtoM, final P p)
  {
    return new TransformedCollection<M, N, P, Collection<M>>(collection,
        funcMtoN, funcNtoM, p);
  }



  /**
   * Returns a view of {@code collection} whose values have been mapped to
   * elements of type {@code N} using {@code funcMtoN}. The returned collection
   * supports all operations.
   *
   * @param <M>
   *          The type of elements contained in {@code collection}.
   * @param <N>
   *          The type of elements contained in the returned collection.
   * @param collection
   *          The collection to be transformed.
   * @param funcMtoN
   *          A function which maps values of type {@code M} to values of type
   *          {@code N}. This function will be used when retrieving values from
   *          {@code collection}.
   * @param funcNtoM
   *          A function which maps values of type {@code N} to values of type
   *          {@code M}. This function will be used when performing queries and
   *          adding values to {@code collection} .
   * @return A view of {@code collection} whose values have been mapped to
   *         elements of type {@code N} using {@code funcMtoN}.
   */
  public static <M, N> Collection<N> transformedCollection(
      final Collection<M> collection,
      final Function<? super M, ? extends N, Void> funcMtoN,
      final Function<? super N, ? extends M, Void> funcNtoM)
  {
    return new TransformedCollection<M, N, Void, Collection<M>>(collection,
        funcMtoN, funcNtoM, null);
  }



  /**
   * Returns a view of {@code list} whose values have been mapped to elements of
   * type {@code N} using {@code funcMtoN}. The returned list supports all
   * operations.
   *
   * @param <M>
   *          The type of elements contained in {@code list}.
   * @param <N>
   *          The type of elements contained in the returned list.
   * @param <P>
   *          The type of the additional parameter to the function's
   *          {@code apply} method. Use {@link java.lang.Void} for functions
   *          that do not need an additional parameter.
   * @param list
   *          The list to be transformed.
   * @param funcMtoN
   *          A function which maps values of type {@code M} to values of type
   *          {@code N}. This function will be used when retrieving values from
   *          {@code list}.
   * @param funcNtoM
   *          A function which maps values of type {@code N} to values of type
   *          {@code M}. This function will be used when performing queries and
   *          adding values to {@code list} .
   * @param p
   *          A predicate specified parameter.
   * @return A view of {@code list} whose values have been mapped to elements of
   *         type {@code N} using {@code funcMtoN}.
   */
  public static <M, N, P> List<N> transformedList(final List<M> list,
      final Function<? super M, ? extends N, P> funcMtoN,
      final Function<? super N, ? extends M, P> funcNtoM, final P p)
  {
    return new TransformedList<M, N, P>(list, funcMtoN, funcNtoM, p);
  }



  /**
   * Returns a view of {@code list} whose values have been mapped to elements of
   * type {@code N} using {@code funcMtoN}. The returned list supports all
   * operations.
   *
   * @param <M>
   *          The type of elements contained in {@code list}.
   * @param <N>
   *          The type of elements contained in the returned list.
   * @param list
   *          The list to be transformed.
   * @param funcMtoN
   *          A function which maps values of type {@code M} to values of type
   *          {@code N}. This function will be used when retrieving values from
   *          {@code list}.
   * @param funcNtoM
   *          A function which maps values of type {@code N} to values of type
   *          {@code M}. This function will be used when performing queries and
   *          adding values to {@code list} .
   * @return A view of {@code list} whose values have been mapped to elements of
   *         type {@code N} using {@code funcMtoN}.
   */
  public static <M, N> List<N> transformedList(final List<M> list,
      final Function<? super M, ? extends N, Void> funcMtoN,
      final Function<? super N, ? extends M, Void> funcNtoM)
  {
    return new TransformedList<M, N, Void>(list, funcMtoN, funcNtoM, null);
  }



  // Prevent instantiation
  private Collections2()
  {
    // Do nothing.
  }

}