001    /*
002     * Copyright 2007-2015 UnboundID Corp.
003     * All Rights Reserved.
004     */
005    /*
006     * Copyright (C) 2008-2015 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     */
021    package com.unboundid.ldap.sdk.controls;
022    
023    
024    
025    import java.io.Serializable;
026    import java.util.ArrayList;
027    
028    import com.unboundid.asn1.ASN1Boolean;
029    import com.unboundid.asn1.ASN1Element;
030    import com.unboundid.asn1.ASN1OctetString;
031    import com.unboundid.asn1.ASN1Sequence;
032    import com.unboundid.ldap.sdk.LDAPException;
033    import com.unboundid.ldap.sdk.ResultCode;
034    import com.unboundid.util.NotMutable;
035    import com.unboundid.util.ThreadSafety;
036    import com.unboundid.util.ThreadSafetyLevel;
037    
038    import static com.unboundid.ldap.sdk.controls.ControlMessages.*;
039    import static com.unboundid.util.Debug.*;
040    import static com.unboundid.util.StaticUtils.*;
041    import static com.unboundid.util.Validator.*;
042    
043    
044    
045    /**
046     * This class provides a data structure for representing a sort key that is to
047     * be used in conjunction with the {@link ServerSideSortRequestControl} for
048     * requesting that the server sort the results before returning them to the
049     * client.
050     * <BR><BR>
051     * A sort key includes the following elements:
052     * <UL>
053     *   <LI>The name of the attribute for which sorting is to be performed.</LI>
054     *   <LI>A {@code reverseOrder} flag that indicates whether the results should
055     *       be sorted in ascending order (if the value is {@code false}) or
056     *       descending order (if the value is {@code true}).</LI>
057     *   <LI>An optional matching rule ID, which specifies the ordering matching
058     *       rule that should be used to perform the sorting.  If this is not
059     *       provided, then the default ordering matching rule for the specified
060     *       attribute will be used.</LI>
061     * </UL>
062     */
063    @NotMutable()
064    @ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
065    public final class SortKey
066           implements Serializable
067    {
068      /**
069       * The BER type that should be used for the matching rule ID element.
070       */
071      private static final byte TYPE_MATCHING_RULE_ID = (byte) 0x80;
072    
073    
074    
075      /**
076       * The BER type that should be used for the reverse order element.
077       */
078      private static final byte TYPE_REVERSE_ORDER = (byte) 0x81;
079    
080    
081    
082      /**
083       * The serial version UID for this serializable class.
084       */
085      private static final long serialVersionUID = -8631224188301402858L;
086    
087    
088    
089      // Indicates whether the sort should be performed in reverse order.
090      private final boolean reverseOrder;
091    
092      // The attribute name for this sort key.
093      private final String attributeName;
094    
095      // The matching rule ID for this sort key.
096      private final String matchingRuleID;
097    
098    
099    
100      /**
101       * Creates a new sort key with the specified attribute name.  It will use the
102       * default ordering matching rule associated with that attribute, and it will
103       * not use reverse order.
104       *
105       * @param  attributeName  The attribute name for this sort key.  It must not
106       *                        be {@code null}.
107       */
108      public SortKey(final String attributeName)
109      {
110        this(attributeName, null, false);
111      }
112    
113    
114    
115      /**
116       * Creates a new sort key with the specified attribute name.  It will use the
117       * default ordering matching rule associated with that attribute.
118       *
119       * @param  attributeName  The attribute name for this sort key.  It must not
120       *                        be {@code null}.
121       * @param  reverseOrder   Indicates whether the sort should be performed in
122       *                        reverse order.
123       */
124      public SortKey(final String attributeName, final boolean reverseOrder)
125      {
126        this(attributeName, null, reverseOrder);
127      }
128    
129    
130    
131      /**
132       * Creates a new sort key with the provided information.
133       *
134       * @param  attributeName   The attribute name for this sort key.  It must not
135       *                         be {@code null}.
136       * @param  matchingRuleID  The name or OID of the ordering matching rule that
137       *                         should be used to perform the sort.  It may be
138       *                         {@code null} if the default ordering matching rule
139       *                         for the specified attribute is to be used.
140       * @param  reverseOrder    Indicates whether the sort should be performed in
141       *                         reverse order.
142       */
143      public SortKey(final String attributeName, final String matchingRuleID,
144                     final boolean reverseOrder)
145      {
146        ensureNotNull(attributeName);
147    
148        this.attributeName  = attributeName;
149        this.matchingRuleID = matchingRuleID;
150        this.reverseOrder   = reverseOrder;
151      }
152    
153    
154    
155      /**
156       * Retrieves the attribute name for this sort key.
157       *
158       * @return  The attribute name for this sort key.
159       */
160      public String getAttributeName()
161      {
162        return attributeName;
163      }
164    
165    
166    
167      /**
168       * Retrieves the name or OID of the ordering matching rule that should be used
169       * to perform the sort, if defined.
170       *
171       * @return  The name or OID of the ordering matching rule that should be used
172       *          to perform the sort, or {@code null} if the sort should use the
173       *          default ordering matching rule associated with the specified
174       *          attribute.
175       */
176      public String getMatchingRuleID()
177      {
178        return matchingRuleID;
179      }
180    
181    
182    
183      /**
184       * Indicates whether the sort should be performed in reverse order.
185       *
186       * @return  {@code true} if the sort should be performed in reverse order, or
187       *          {@code false} if it should be performed in the standard order for
188       *          the associated ordering matching rule.
189       */
190      public boolean reverseOrder()
191      {
192        return reverseOrder;
193      }
194    
195    
196    
197      /**
198       * Encodes this sort key into an ASN.1 sequence suitable for use in the
199       * server-side sort control.
200       *
201       * @return  An ASN.1 sequence containing the encoded representation of this
202       *          sort key.
203       */
204      ASN1Sequence encode()
205      {
206        final ArrayList<ASN1Element> elements = new ArrayList<ASN1Element>(3);
207        elements.add(new ASN1OctetString(attributeName));
208    
209        if (matchingRuleID != null)
210        {
211          elements.add(new ASN1OctetString(TYPE_MATCHING_RULE_ID, matchingRuleID));
212        }
213    
214        if (reverseOrder)
215        {
216          elements.add(new ASN1Boolean(TYPE_REVERSE_ORDER, reverseOrder));
217        }
218    
219        return new ASN1Sequence(elements);
220      }
221    
222    
223    
224      /**
225       * Decodes the provided ASN.1 element as a sort key.
226       *
227       * @param  element  The ASN.1 element to decode as a sort key.
228       *
229       * @return  The decoded sort key.
230       *
231       * @throws  LDAPException  If the provided ASN.1 element cannot be decoded as
232       *                         a sort key.
233       */
234      public static SortKey decode(final ASN1Element element)
235             throws LDAPException
236      {
237        final ASN1Element[] elements;
238        try
239        {
240          elements = ASN1Sequence.decodeAsSequence(element).elements();
241        }
242        catch (Exception e)
243        {
244          debugException(e);
245          throw new LDAPException(ResultCode.DECODING_ERROR,
246                                  ERR_SORT_KEY_NOT_SEQUENCE.get(e), e);
247        }
248    
249        if ((elements.length < 1) || (elements.length > 3))
250        {
251          throw new LDAPException(ResultCode.DECODING_ERROR,
252                                  ERR_SORT_KEY_INVALID_ELEMENT_COUNT.get(
253                                       elements.length));
254        }
255    
256        boolean reverseOrder   = false;
257        String  matchingRuleID = null;
258        final String  attributeName  =
259             ASN1OctetString.decodeAsOctetString(elements[0]).stringValue();
260        for (int i=1; i < elements.length; i++)
261        {
262          switch (elements[i].getType())
263          {
264            case TYPE_MATCHING_RULE_ID:
265              matchingRuleID =
266                   ASN1OctetString.decodeAsOctetString(elements[i]).stringValue();
267              break;
268    
269            case TYPE_REVERSE_ORDER:
270              try
271              {
272                reverseOrder =
273                     ASN1Boolean.decodeAsBoolean(elements[i]).booleanValue();
274              }
275              catch (Exception e)
276              {
277                debugException(e);
278                throw new LDAPException(ResultCode.DECODING_ERROR,
279                                        ERR_SORT_KEY_REVERSE_NOT_BOOLEAN.get(e), e);
280              }
281              break;
282    
283            default:
284              throw new LDAPException(ResultCode.DECODING_ERROR,
285                                      ERR_SORT_KEY_ELEMENT_INVALID_TYPE.get(
286                                           toHex(elements[i].getType())));
287          }
288        }
289    
290        return new SortKey(attributeName, matchingRuleID, reverseOrder);
291      }
292    
293    
294    
295      /**
296       * Retrieves a string representation of this sort key.
297       *
298       * @return  A string representation of this sort key.
299       */
300      @Override()
301      public String toString()
302      {
303        final StringBuilder buffer = new StringBuilder();
304        toString(buffer);
305        return buffer.toString();
306      }
307    
308    
309    
310      /**
311       * Appends a string representation of this sort key to the provided buffer.
312       *
313       * @param  buffer  The buffer to which to append a string representation of
314       *                 this sort key.
315       */
316      public void toString(final StringBuilder buffer)
317      {
318        buffer.append("SortKey(attributeName=");
319        buffer.append(attributeName);
320    
321        if (matchingRuleID != null)
322        {
323          buffer.append(", matchingRuleID=");
324          buffer.append(matchingRuleID);
325        }
326    
327        buffer.append(", reverseOrder=");
328        buffer.append(reverseOrder);
329        buffer.append(')');
330      }
331    }