/*
 * 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 legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * 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 legal-notices/CDDLv1_0.txt.
 * 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 2006-2008 Sun Microsystems, Inc.
 *      Portions Copyright 2014-2015 ForgeRock AS
 */
package org.opends.server.types;

/**
 * This class defines a Directory Server cache entry, which is simply
 * used to store an entry with its associated backend and entry ID.
 */
@org.opends.server.types.PublicAPI(
     stability=org.opends.server.types.StabilityLevel.VOLATILE,
     mayInstantiate=true,
     mayExtend=false,
     mayInvoke=true,
     notes="This should only be used within a backend")
public final class CacheEntry
{
  /** ID of the backend with which this cache entry is associated. */
  private final String backendID;

  /** The entry itself. */
  private final Entry entry;

  /** The entry ID for the entry within the backend. */
  private final long entryID;

  /**
   * Creates a new cache entry with the provided information.
   *
   * @param  entry    The entry for this cache entry.
   * @param  backendID  ID of the backend for this cache entry.
   * @param  entryID  The entry ID for this cache entry.
   */
  public CacheEntry(Entry entry, String backendID, long entryID)
  {
    this.entry   = entry;
    this.backendID = backendID;
    this.entryID = entryID;
  }

  /**
   * Retrieves the entry for this cache entry.
   *
   * @return  The entry for this cache entry.
   */
  public Entry getEntry()
  {
    return entry;
  }

  /**
   * Retrieves the backend ID for this cache entry.
   *
   * @return  ID of the backend for this cache entry.
   */
  public String getBackendID()
  {
    return backendID;
  }

  /**
   * Retrieves the entry ID for this cache entry.
   *
   * @return  The entry ID for this cache entry.
   */
  public long getEntryID()
  {
    return entryID;
  }

  /**
   * Retrieves the DN for this cache entry.
   *
   * @return  The DN for this cache entry.
   */
  public DN getDN()
  {
    return entry.getName();
  }

  /**
   * Retrieves the hash code for this cache entry.  It will be the
   * integer representation of the entry ID.
   *
   * @return  The hash code for this cache entry.
   */
  @Override
  public int hashCode()
  {
    return (int) entryID;
  }

  /**
   * Indicates whether this cache entry is equal to the provided \
   * object.  They will be considered equal if the provided object is
   * a cache entry with the same entry and entry ID.
   *
   * @param  o  The object for which to make the determination.
   *
   * @return  <CODE>true</CODE> if the provided object is equal to
   *          this cache entry, or <CODE>false</CODE> if not.
   */
  @Override
  public boolean equals(Object o)
  {
    if (o == null)
    {
      return false;
    }

    if (o == this)
    {
      return true;
    }

    if (! (o instanceof CacheEntry))
    {
      return false;
    }

    CacheEntry e = (CacheEntry) o;
    return e.entryID == entryID && e.entry.equals(entry);
  }
}