/*
 * 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:
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 * CDDL HEADER END
 *
 *
 *      Portions Copyright 2006-2007 Sun Microsystems, Inc.
 */
package org.opends.server.schema;



import java.text.SimpleDateFormat;
import java.util.TimeZone;
import java.util.concurrent.locks.ReentrantLock;

import org.opends.server.admin.std.server.EqualityMatchingRuleCfg;
import org.opends.server.api.EqualityMatchingRule;
import org.opends.server.config.ConfigException;
import org.opends.server.core.DirectoryServer;
import org.opends.server.protocols.asn1.ASN1OctetString;
import org.opends.server.types.ByteString;
import org.opends.server.types.DirectoryException;
import org.opends.server.types.ErrorLogCategory;
import org.opends.server.types.ErrorLogSeverity;
import org.opends.server.types.InitializationException;

import org.opends.server.types.DebugLogLevel;
import static org.opends.server.loggers.ErrorLogger.*;
import static org.opends.server.loggers.debug.DebugLogger.*;
import org.opends.server.loggers.debug.DebugTracer;
import static org.opends.server.schema.SchemaConstants.*;
import static org.opends.server.util.ServerConstants.*;


/**
 * This class defines the generalizedTimeMatch matching rule defined in X.520
 * and referenced in RFC 2252.
 */
public class GeneralizedTimeEqualityMatchingRule
       extends EqualityMatchingRule
{
  /**
   * The tracer object for the debug logger.
   */
  private static final DebugTracer TRACER = getTracer();

  /**
   * The lock that will be used to provide threadsafe access to the date
   * formatter.
   */
  private static ReentrantLock dateFormatLock;



  /**
   * The date formatter that will be used to convert dates into generalized time
   * values.  Note that all interaction with it must be synchronized.
   */
  private static SimpleDateFormat dateFormat;



  /**
   * The time zone used for UTC time.
   */
  private static TimeZone utcTimeZone;



  /*
   * Create the date formatter that will be used to construct and parse
   * normalized generalized time values.
   */
  static
  {
    utcTimeZone = TimeZone.getTimeZone("UTC");

    dateFormat = new SimpleDateFormat(DATE_FORMAT_GENERALIZED_TIME);
    dateFormat.setLenient(false);
    dateFormat.setTimeZone(utcTimeZone);

    dateFormatLock = new ReentrantLock();
  }



  /**
   * Creates a new instance of this generalizedTimeMatch matching rule.
   */
  public GeneralizedTimeEqualityMatchingRule()
  {
    super();
  }



  /**
   * {@inheritDoc}
   */
  public void initializeMatchingRule(EqualityMatchingRuleCfg configuration)
         throws ConfigException, InitializationException
  {
    // No initialization is required.
  }



  /**
   * Retrieves the common name for this matching rule.
   *
   * @return  The common name for this matching rule, or <CODE>null</CODE> if
   * it does not have a name.
   */
  public String getName()
  {
    return EMR_GENERALIZED_TIME_NAME;
  }



  /**
   * Retrieves the OID for this matching rule.
   *
   * @return  The OID for this matching rule.
   */
  public String getOID()
  {
    return EMR_GENERALIZED_TIME_OID;
  }



  /**
   * Retrieves the description for this matching rule.
   *
   * @return  The description for this matching rule, or <CODE>null</CODE> if
   *          there is none.
   */
  public String getDescription()
  {
    // There is no standard description for this matching rule.
    return null;
  }



  /**
   * Retrieves the OID of the syntax with which this matching rule is
   * associated.
   *
   * @return  The OID of the syntax with which this matching rule is associated.
   */
  public String getSyntaxOID()
  {
    return SYNTAX_GENERALIZED_TIME_OID;
  }



  /**
   * Retrieves the normalized form of the provided value, which is best suited
   * for efficiently performing matching operations on that value.
   *
   * @param  value  The value to be normalized.
   *
   * @return  The normalized version of the provided value.
   *
   * @throws  DirectoryException  If the provided value is invalid according to
   *                              the associated attribute syntax.
   */
  public ByteString normalizeValue(ByteString value)
         throws DirectoryException
  {
    try
    {
      long timestamp = GeneralizedTimeSyntax.decodeGeneralizedTimeValue(value);
      return new ASN1OctetString(GeneralizedTimeSyntax.format(timestamp));
    }
    catch (DirectoryException de)
    {
      if (debugEnabled())
      {
        TRACER.debugCaught(DebugLogLevel.ERROR, de);
      }

      switch (DirectoryServer.getSyntaxEnforcementPolicy())
      {
        case REJECT:
          throw de;

        case WARN:
          logError(ErrorLogCategory.SCHEMA, ErrorLogSeverity.SEVERE_WARNING,
                   de.getErrorMessage(), de.getMessageID());
          return new ASN1OctetString(value.value());

        default:
          return new ASN1OctetString(value.value());
      }
    }
  }



  /**
   * Indicates whether the two provided normalized values are equal to each
   * other.
   *
   * @param  value1  The normalized form of the first value to compare.
   * @param  value2  The normalized form of the second value to compare.
   *
   * @return  <CODE>true</CODE> if the provided values are equal, or
   *          <CODE>false</CODE> if not.
   */
  public boolean areEqual(ByteString value1, ByteString value2)
  {
    try
    {
      long time1 = GeneralizedTimeSyntax.decodeGeneralizedTimeValue(value1);
      long time2 = GeneralizedTimeSyntax.decodeGeneralizedTimeValue(value2);
      return (time1 == time2);
    }
    catch (DirectoryException de)
    {
      if (debugEnabled())
      {
        TRACER.debugCaught(DebugLogLevel.ERROR, de);
      }

      return false;
    }
  }
}