/*
 * 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
 *
 *
 *      Portions Copyright 2006 Sun Microsystems, Inc.
 */
package org.opends.server.backends.jeb;

import org.opends.server.protocols.asn1.ASN1OctetString;
import org.opends.server.types.Attribute;
import org.opends.server.types.Entry;
import org.opends.server.types.Modification;

import com.sleepycat.je.Transaction;
import com.sleepycat.je.DatabaseException;

import java.util.Comparator;
import java.util.List;
import java.util.Set;

/**
 * An implementation of an Indexer for attribute presence.
 */
public class PresenceIndexer extends Indexer
{
  /**
   * The fully-qualified name of this class for debugging purposes.
   */
  private static final String CLASS_NAME =
       "org.opends.server.backends.jeb.PresenceIndexer";


  /**
   * The comparator for index keys generated by this class.
   */
  private static final Comparator<byte[]> comparator =
       new AttributeIndex.KeyComparator();

  /**
   * The attribute index configuration for which this instance will
   * generate index keys.
   */
  private IndexConfig indexConfig;

  /**
   * Create a new attribute presence indexer.
   * @param indexConfig The attribute index configuration for which the indexer
   * is required.
   */
  public PresenceIndexer(IndexConfig indexConfig)
  {
    this.indexConfig = indexConfig;
  }

  /**
   * Get a string representation of this object.
   * @return A string representation of this object.
   */
  public String toString()
  {
    return indexConfig.getAttributeType().getNameOrOID() + ".presence";
  }

  /**
   * Get the comparator that must be used to compare index keys
   * generated by this class.
   *
   * @return A byte array comparator.
   */
  public Comparator<byte[]> getComparator()
  {
    return comparator;
  }



  /**
   * Generate the set of index keys for an entry.
   *
   * @param txn A database transaction to be used if the database need to be
   * accessed in the course of generating the index keys.
   * @param entry The entry.
   * @param keys The set into which the generated keys will be inserted.
   * @throws DatabaseException If an error occurs in the JE database.
   */
  public void indexEntry(Transaction txn, Entry entry,
                       Set<ASN1OctetString> keys) throws DatabaseException
  {
    List<Attribute> attrList =
         entry.getAttribute(indexConfig.getAttributeType());
    if (attrList != null)
    {
      if (!attrList.isEmpty())
      {
        keys.add(new ASN1OctetString(AttributeIndex.presenceKey.getData()));
      }
    }
  }



  /**
   * Generate the set of index keys to be added and the set of index keys
   * to be deleted for an entry that has been replaced.
   *
   * @param txn A database transaction to be used if the database need to be
   * accessed in the course of generating the index keys.
   * @param oldEntry The original entry contents.
   * @param newEntry The new entry contents.
   * @param addKeys The set into which the keys to be added will be inserted.
   * @param delKeys The set into which the keys to be deleted will be inserted.
   * @throws DatabaseException If an error occurs in the JE database.
   */
  public void replaceEntry(Transaction txn, Entry oldEntry, Entry newEntry,
                           Set<ASN1OctetString> addKeys,
                           Set<ASN1OctetString> delKeys)
       throws DatabaseException
  {
    List<Attribute> beforeList, afterList;

    beforeList = oldEntry.getAttribute(indexConfig.getAttributeType());
    afterList = newEntry.getAttribute(indexConfig.getAttributeType());

    if (beforeList == null || beforeList.isEmpty())
    {
      if (afterList != null && !afterList.isEmpty())
      {
        addKeys.add(new ASN1OctetString(AttributeIndex.presenceKey.getData()));
      }
    }
    else if (afterList == null || afterList.isEmpty())
    {
      delKeys.add(new ASN1OctetString(AttributeIndex.presenceKey.getData()));
    }
  }



  /**
   * Generate the set of index keys to be added and the set of index keys
   * to be deleted for an entry that was modified.
   *
   * @param txn A database transaction to be used if the database need to be
   * accessed in the course of generating the index keys.
   * @param oldEntry The original entry contents.
   * @param newEntry The new entry contents.
   * @param mods The set of modifications that were applied to the entry.
   * @param addKeys The set into which the keys to be added will be inserted.
   * @param delKeys The set into which the keys to be deleted will be inserted.
   * @throws DatabaseException If an error occurs in the JE database.
   */
  public void modifyEntry(Transaction txn, Entry oldEntry, Entry newEntry,
                          List<Modification> mods,
                          Set<ASN1OctetString> addKeys,
                          Set<ASN1OctetString> delKeys)
       throws DatabaseException
  {
    replaceEntry(txn, oldEntry, newEntry, addKeys, delKeys);
  }
}