/*
 * 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 2006-2008 Sun Microsystems, Inc.
 */
package org.opends.server.controls;
import org.opends.messages.Message;


import org.opends.server.protocols.asn1.*;
import static org.opends.server.protocols.asn1.ASN1Constants.
    UNIVERSAL_OCTET_STRING_TYPE;
import org.opends.server.protocols.ldap.SearchResultEntryProtocolOp;
import org.opends.server.protocols.ldap.LDAPReader;
import org.opends.server.types.*;

import static org.opends.server.loggers.debug.DebugLogger.*;
import org.opends.server.loggers.debug.DebugTracer;
import static org.opends.messages.ProtocolMessages.*;
import static org.opends.server.util.ServerConstants.*;

import java.io.IOException;


/**
 * This class implements the pre-read response control as defined in RFC 4527.
 * This control holds the search result entry representing the state of the
 * entry immediately before a modify, delete, or modify DN operation.
 */
public class LDAPPreReadResponseControl
       extends Control
{
  /**
   * ControlDecoder implentation to decode this control from a ByteString.
   */
  private final static class Decoder
      implements ControlDecoder<LDAPPreReadResponseControl>
  {
    /**
     * {@inheritDoc}
     */
    public LDAPPreReadResponseControl decode(boolean isCritical,
                                             ByteString value)
        throws DirectoryException
    {
     if (value == null)
      {
        Message message = ERR_PREREADRESP_NO_CONTROL_VALUE.get();
        throw new DirectoryException(ResultCode.PROTOCOL_ERROR, message);
      }


      ASN1Reader reader = ASN1.getReader(value);
      SearchResultEntry searchEntry;
      try
      {
        SearchResultEntryProtocolOp searchResultEntryProtocolOp =
            LDAPReader.readSearchEntry(reader);
        searchEntry = searchResultEntryProtocolOp.toSearchResultEntry();
      }
      catch (LDAPException le)
      {
        if (debugEnabled())
        {
          TRACER.debugCaught(DebugLogLevel.ERROR, le);
        }

        Message message =
            ERR_PREREADRESP_CANNOT_DECODE_VALUE.get(le.getMessage());
        throw new DirectoryException(ResultCode.PROTOCOL_ERROR, message,
            le);
      }

      return new LDAPPreReadResponseControl(isCritical, searchEntry);
    }

    public String getOID()
    {
      return OID_LDAP_READENTRY_PREREAD;
    }

  }

  /**
   * The Control Decoder that can be used to decode this control.
   */
  public static final ControlDecoder<LDAPPreReadResponseControl> DECODER =
    new Decoder();

  /**
   * The tracer object for the debug logger.
   */
  private static final DebugTracer TRACER = getTracer();




  // The search result entry to include in the response control.
  private SearchResultEntry searchEntry;



  /**
   * Creates a new instance of this LDAP pre-read response control with the
   * provided information.
   *
   * @param  searchEntry  The search result entry to include in the response
   *                      control.
   */
  public LDAPPreReadResponseControl(SearchResultEntry searchEntry)
  {
    this(false, searchEntry);
  }



  /**
   * Creates a new instance of this LDAP pre-read response control with the
   * provided information.
   *
   * @param  isCritical   Indicates whether support for this control should be
   *                      considered a critical part of the server processing.
   * @param  searchEntry  The search result entry to include in the response
   *                      control.
   */
  public LDAPPreReadResponseControl(boolean isCritical,
                                    SearchResultEntry searchEntry)
  {
    super(OID_LDAP_READENTRY_PREREAD, isCritical);


    this.searchEntry = searchEntry;
  }



  /**
   * Writes this control's value to an ASN.1 writer. The value (if any) must be
   * written as an ASN1OctetString.
   *
   * @param writer The ASN.1 output stream to write to.
   * @throws IOException If a problem occurs while writing to the stream.
   */
  @Override
  public void writeValue(ASN1Writer writer) throws IOException {
    writer.writeStartSequence(UNIVERSAL_OCTET_STRING_TYPE);

    SearchResultEntryProtocolOp protocolOp =
        new SearchResultEntryProtocolOp(searchEntry);

    protocolOp.write(writer);
    writer.writeEndSequence();
  }



  /**
   * Retrieves the search result entry associated with this pre-read response
   * control.
   *
   * @return  The search result entry associated with this pre-read response
   *          control.
   */
  public SearchResultEntry getSearchEntry()
  {
    return searchEntry;
  }



  /**
   * Appends a string representation of this LDAP pre-read response control to
   * the provided buffer.
   *
   * @param  buffer  The buffer to which the information should be appended.
   */
  @Override
  public void toString(StringBuilder buffer)
  {
    buffer.append("LDAPPreReadResponseControl(criticality=");
    buffer.append(isCritical());
    buffer.append(",entry=");
    searchEntry.toSingleLineString(buffer);
    buffer.append(")");
  }
}