001/*
002 * Copyright 2007-2014 UnboundID Corp.
003 * All Rights Reserved.
004 */
005/*
006 * Copyright (C) 2008-2014 UnboundID Corp.
007 *
008 * This program is free software; you can redistribute it and/or modify
009 * it under the terms of the GNU General Public License (GPLv2 only)
010 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
011 * as published by the Free Software Foundation.
012 *
013 * This program is distributed in the hope that it will be useful,
014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016 * GNU General Public License for more details.
017 *
018 * You should have received a copy of the GNU General Public License
019 * along with this program; if not, see <http://www.gnu.org/licenses>.
020 */
021package com.unboundid.ldap.sdk.controls;
022
023
024
025import com.unboundid.asn1.ASN1Element;
026import com.unboundid.asn1.ASN1OctetString;
027import com.unboundid.asn1.ASN1Sequence;
028import com.unboundid.ldap.sdk.Control;
029import com.unboundid.ldap.sdk.LDAPException;
030import com.unboundid.ldap.sdk.ResultCode;
031import com.unboundid.util.NotMutable;
032import com.unboundid.util.StaticUtils;
033import com.unboundid.util.ThreadSafety;
034import com.unboundid.util.ThreadSafetyLevel;
035
036import static com.unboundid.ldap.sdk.controls.ControlMessages.*;
037import static com.unboundid.util.Debug.*;
038
039
040
041/**
042 * This class provides an implementation of the LDAP pre-read request control
043 * as defined in <A HREF="http://www.ietf.org/rfc/rfc4527.txt">RFC 4527</A>.  It
044 * may be used to request that the server retrieve a copy of the target entry as
045 * it appeared immediately before processing a delete, modify, or modify DN
046 * operation.
047 * <BR><BR>
048 * If this control is included in a delete, modify, or modify DN request, then
049 * the corresponding response may include a {@link PreReadResponseControl}
050 * containing a version of the entry as it before after applying that change.
051 * Note that this response control will only be included if the operation was
052 * successful, so it will not be provided if the operation failed for some
053 * reason (e.g., if the change would have violated the server schema, or if the
054 * requester did not have sufficient permission to perform that operation).
055 * <BR><BR>
056 * The value of this control should contain a set of requested attributes to
057 * include in the entry that is returned.  The server should treat this set of
058 * requested attributes exactly as it treats the requested attributes from a
059 * {@link com.unboundid.ldap.sdk.SearchRequest}.  As is the case with a search
060 * request, if no attributes are specified, then all user attributes will be
061 * included.
062 * <BR><BR>
063 * The use of the LDAP pre-read request control is virtually identical to the
064 * use of the LDAP post-read request control.  See the documentation for the
065 * {@link PostReadRequestControl} for an example that illustrates its use.
066 */
067@NotMutable()
068@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
069public final class PreReadRequestControl
070       extends Control
071{
072  /**
073   * The OID (1.3.6.1.1.13.1) for the pre-read request control.
074   */
075  public static final String PRE_READ_REQUEST_OID = "1.3.6.1.1.13.1";
076
077
078
079  /**
080   * The set of requested attributes that will be used if none are provided.
081   */
082  private static final String[] NO_ATTRIBUTES = StaticUtils.NO_STRINGS;
083
084
085
086  /**
087   * The serial version UID for this serializable class.
088   */
089  private static final long serialVersionUID = 1205235290978028739L;
090
091
092
093  // The set of requested attributes to retrieve from the target entry.
094  private final String[] attributes;
095
096
097
098  /**
099   * Creates a new pre-read request control that will retrieve the specified set
100   * of attributes from the target entry.  It will be marked critical.
101   *
102   * @param  attributes  The set of attributes to retrieve from the target
103   *                     entry.  It behaves in the same way as the set of
104   *                     requested attributes for a search operation.  If this
105   *                     is empty or {@code null}, then all user attributes
106   *                     will be returned.
107   */
108  public PreReadRequestControl(final String... attributes)
109  {
110    this(true, attributes);
111  }
112
113
114
115  /**
116   * Creates a new pre-read request control that will retrieve the specified set
117   * of attributes from the target entry.
118   *
119   * @param  isCritical  Indicates whether this control should be marked
120   *                     critical.
121   * @param  attributes  The set of attributes to retrieve from the target
122   *                     entry.  It behaves in the same way as the set of
123   *                     requested attributes for a search operation.  If this
124   *                     is empty or {@code null}, then all user attributes
125   *                     will be returned.
126   */
127  public PreReadRequestControl(final boolean isCritical,
128                               final String... attributes)
129  {
130    super(PRE_READ_REQUEST_OID, isCritical, encodeValue(attributes));
131
132    if (attributes == null)
133    {
134      this.attributes = NO_ATTRIBUTES;
135    }
136    else
137    {
138      this.attributes = attributes;
139    }
140  }
141
142
143
144  /**
145   * Creates a new pre-read request control which is decoded from the provided
146   * generic control.
147   *
148   * @param  control  The generic control to be decoded as a pre-read request
149   *                  control.
150   *
151   * @throws  LDAPException  If the provided control cannot be decoded as a
152   *                         pre-read request control.
153   */
154  public PreReadRequestControl(final Control control)
155         throws LDAPException
156  {
157    super(control);
158
159    final ASN1OctetString value = control.getValue();
160    if (value == null)
161    {
162      throw new LDAPException(ResultCode.DECODING_ERROR,
163                              ERR_PRE_READ_REQUEST_NO_VALUE.get());
164    }
165
166    try
167    {
168      final ASN1Element valueElement = ASN1Element.decode(value.getValue());
169      final ASN1Element[] attrElements =
170           ASN1Sequence.decodeAsSequence(valueElement).elements();
171      attributes = new String[attrElements.length];
172      for (int i=0; i < attrElements.length; i++)
173      {
174        attributes[i] =
175             ASN1OctetString.decodeAsOctetString(attrElements[i]).stringValue();
176      }
177    }
178    catch (Exception e)
179    {
180      debugException(e);
181      throw new LDAPException(ResultCode.DECODING_ERROR,
182                              ERR_PRE_READ_REQUEST_CANNOT_DECODE.get(e), e);
183    }
184  }
185
186
187
188  /**
189   * Encodes the provided information into an octet string that can be used as
190   * the value for this control.
191   *
192   * @param  attributes  The set of attributes to retrieve from the target
193   *                     entry.  It behaves in the same way as the set of
194   *                     requested attributes for a search operation.  If this
195   *                     is empty or {@code null}, then all user attributes
196   *                     will be returned.
197   *
198   * @return  An ASN.1 octet string that can be used as the value for this
199   *          control.
200   */
201  private static ASN1OctetString encodeValue(final String[] attributes)
202  {
203    if ((attributes == null) || (attributes.length == 0))
204    {
205      return new ASN1OctetString(new ASN1Sequence().encode());
206    }
207
208    final ASN1OctetString[] elements = new ASN1OctetString[attributes.length];
209    for (int i=0; i < attributes.length; i++)
210    {
211      elements[i] = new ASN1OctetString(attributes[i]);
212    }
213
214    return new ASN1OctetString(new ASN1Sequence(elements).encode());
215  }
216
217
218
219  /**
220   * Retrieves the set of attributes that will be requested for inclusion in the
221   * entry returned in the response control.
222   *
223   * @return  The set of attributes that will be requested for inclusion in the
224   *          entry returned in the response control, or an empty array if all
225   *          user attributes should be returned.
226   */
227  public String[] getAttributes()
228  {
229    return attributes;
230  }
231
232
233
234  /**
235   * {@inheritDoc}
236   */
237  @Override()
238  public String getControlName()
239  {
240    return INFO_CONTROL_NAME_PRE_READ_REQUEST.get();
241  }
242
243
244
245  /**
246   * {@inheritDoc}
247   */
248  @Override()
249  public void toString(final StringBuilder buffer)
250  {
251    buffer.append("PreReadRequestControl(attributes={");
252    for (int i=0; i < attributes.length; i++)
253    {
254      if (i > 0)
255      {
256        buffer.append(", ");
257      }
258      buffer.append('\'');
259      buffer.append(attributes[i]);
260      buffer.append('\'');
261    }
262    buffer.append("}, isCritical=");
263    buffer.append(isCritical());
264    buffer.append(')');
265  }
266}