001/*
002 * CDDL HEADER START
003 *
004 * The contents of this file are subject to the terms of the
005 * Common Development and Distribution License, Version 1.0 only
006 * (the "License").  You may not use this file except in compliance
007 * with the License.
008 *
009 * You can obtain a copy of the license at
010 * docs/licenses/cddl.txt
011 * or http://www.opensource.org/licenses/cddl1.php.
012 * See the License for the specific language governing permissions
013 * and limitations under the License.
014 *
015 * When distributing Covered Code, include this CDDL HEADER in each
016 * file and include the License file at
017 * docs/licenses/cddl.txt.  If applicable,
018 * add the following below this CDDL HEADER, with the fields enclosed
019 * by brackets "[]" replaced with your own identifying information:
020 *      Portions Copyright [yyyy] [name of copyright owner]
021 *
022 * CDDL HEADER END
023 *
024 *
025 *      Copyright 2010-2019 Ping Identity Corporation
026 */
027package com.unboundid.directory.sdk.proxy.api;
028
029
030
031import java.util.Collections;
032import java.util.List;
033import java.util.Map;
034
035import com.unboundid.directory.sdk.common.internal.ExampleUsageProvider;
036import com.unboundid.directory.sdk.common.internal.Reconfigurable;
037import com.unboundid.directory.sdk.common.internal.UnboundIDExtension;
038import com.unboundid.directory.sdk.common.operation.AddRequest;
039import com.unboundid.directory.sdk.common.types.OperationContext;
040import com.unboundid.directory.sdk.proxy.config.PlacementAlgorithmConfig;
041import com.unboundid.directory.sdk.proxy.internal.DirectoryProxyServerExtension;
042import com.unboundid.directory.sdk.proxy.types.BackendSet;
043import com.unboundid.directory.sdk.proxy.types.ProxyServerContext;
044import com.unboundid.ldap.sdk.LDAPException;
045import com.unboundid.ldap.sdk.ResultCode;
046import com.unboundid.util.Extensible;
047import com.unboundid.util.ThreadSafety;
048import com.unboundid.util.ThreadSafetyLevel;
049import com.unboundid.util.args.ArgumentException;
050import com.unboundid.util.args.ArgumentParser;
051
052
053
054/**
055 * This class defines an API that must be implemented by extensions which are
056 * used to select the backend set in which a new entry should be added in an
057 * entry-balanced environment.  The decision may be based on a wide range of
058 * factors, including the contents of the entry to be added, the number of
059 * entries in each of the backend servers, or other kinds of criteria.
060 * <BR><BR>
061 * Note that the placement algorithm will only be used for entries which are
062 * immediate subordinates of the entry which is the balancing point.  Entries
063 * which are more than one level below the balancing point will automatically
064 * be added into the same backend set as their parent entry.
065 * <BR>
066 * <H2>Configuring Placement Algorithms</H2>
067 * In order to configure a placement algorithm created using this API, use a
068 * command like:
069 * <PRE>
070 *      dsconfig create-placement-algorithm \
071 *           --algorithm-name "<I>{algorithm-name}</I>" \
072 *           --processor-name "<I>{processor-name}</I>" \
073 *           --type third-party \
074 *           --set enabled:true \
075 *           --set "extension-class:<I>{class-name}</I>" \
076 *           --set "extension-argument:<I>{name=value}</I>"
077 * </PRE>
078 * where "<I>{algorithm-name}</I>" is the to use for the placement algorithm
079 * instance, "<I>{processor-name}</I>" is the name of the entry-balancing
080 * request processor for which the placement algorithm will be used,
081 * "<I>{class-name}</I>" is the fully-qualified name of the Java class
082 * that extends
083 * {@code com.unboundid.directory.sdk.proxy.api.PlacementAlgorithm}, and
084 * "<I>{name=value}</I>" represents name-value pairs for any arguments to
085 * provide to the placement algorithm.  If multiple arguments should be provided
086 * to the placement algorithm, then the
087 * "<CODE>--set extension-argument:<I>{name=value}</I></CODE>" option should be
088 * provided multiple times.
089 */
090@Extensible()
091@DirectoryProxyServerExtension(appliesToLocalContent=false,
092     appliesToRemoteContent=true)
093@ThreadSafety(level=ThreadSafetyLevel.INTERFACE_THREADSAFE)
094public abstract class PlacementAlgorithm
095       implements UnboundIDExtension, Reconfigurable<PlacementAlgorithmConfig>,
096                  ExampleUsageProvider
097{
098  /**
099   * Creates a new instance of this placement algorithm.  All placement
100   * algorithm implementations must include a default constructor, but any
101   * initialization should generally be done in the
102   * {@code initializePlacementAlgorithm} method.
103   */
104  public PlacementAlgorithm()
105  {
106    // No implementation is required.
107  }
108
109
110
111  /**
112   * {@inheritDoc}
113   */
114  public abstract String getExtensionName();
115
116
117
118  /**
119   * {@inheritDoc}
120   */
121  public abstract String[] getExtensionDescription();
122
123
124
125  /**
126   * {@inheritDoc}
127   */
128  public void defineConfigArguments(final ArgumentParser parser)
129         throws ArgumentException
130  {
131    // No arguments will be allowed by default.
132  }
133
134
135
136  /**
137   * Initializes this placement algorithm.
138   *
139   * @param  serverContext    A handle to the server context for the Directory
140   *                          Proxy server in which this extension is running.
141   * @param  config           The general configuration for this placement
142   *                          algorithm.
143   * @param  parser           The argument parser which has been initialized
144   *                          from the configuration for this placement
145   *                          algorithm..
146   * @param  balancingBaseDN  The balancing base DN for the associated
147   *                          entry-balancing request processor.
148   * @param  backendSets      The list of backend sets that will be used with
149   *                          the entry-balancing request processor.
150   *
151   * @throws  LDAPException  If a problem occurs while initializing this LDAP
152   *                         health check.
153   */
154  public void initializePlacementAlgorithm(
155                   final ProxyServerContext serverContext,
156                   final PlacementAlgorithmConfig config,
157                   final ArgumentParser parser,
158                   final String balancingBaseDN,
159                   final List<BackendSet> backendSets)
160         throws LDAPException
161  {
162    // No initialization will be performed by default.
163  }
164
165
166
167  /**
168   * {@inheritDoc}
169   */
170  public boolean isConfigurationAcceptable(
171                      final PlacementAlgorithmConfig config,
172                      final ArgumentParser parser,
173                      final List<String> unacceptableReasons)
174  {
175    // No extended validation will be performed by default.
176    return true;
177  }
178
179
180
181  /**
182   * {@inheritDoc}
183   */
184  public ResultCode applyConfiguration(final PlacementAlgorithmConfig config,
185                                       final ArgumentParser parser,
186                                       final List<String> adminActionsRequired,
187                                       final List<String> messages)
188  {
189    // By default, no configuration changes will be applied.  If there are any
190    // arguments, then add an admin action message indicating that the extension
191    // needs to be restarted for any changes to take effect.
192    if (! parser.getNamedArguments().isEmpty())
193    {
194      adminActionsRequired.add(
195           "No configuration change has actually been applied.  The new " +
196                "configuration will not take effect until this placement " +
197                "algorithm is disabled and re-enabled or until the server " +
198                "is restarted.");
199    }
200
201    return ResultCode.SUCCESS;
202  }
203
204
205
206  /**
207   * Performs any cleanup which may be necessary when this LDAP health check is
208   * to be taken out of service.
209   */
210  public void finalizePlacementAlgorithm()
211  {
212    // No implementation is required.
213  }
214
215
216
217  /**
218   * Adapts to a change in the backend sets configured for use with the
219   * associated entry-balancing request processor.
220   *
221   * @param  balancingBaseDN  The updated balancing base DN for the associated
222   *                          entry-balancing request processor.
223   * @param  backendSets      The updated list of backend sets for the
224   *                          associated entry-balancing request processor.
225   */
226  public abstract void applyBalancingConfigurationChange(
227                            final String balancingBaseDN,
228                            final List<BackendSet> backendSets);
229
230
231
232  /**
233   * Determines the backend set that should be used to process the specified
234   * add operation.
235   *
236   * @param  operationContext  The operation context for the add operation
237   *                           to be processed.
238   * @param  addRequest        The add request being processed.
239   *
240   * @return  The backend set in which the add should be processed, or
241   *          {@code null} if there is no appropriate backend set.
242   */
243  public abstract BackendSet selectBackendSet(
244                                  final OperationContext operationContext,
245                                  final AddRequest addRequest);
246
247
248
249  /**
250   * Select a new backend set for an entry that has been modified or a child
251   * entry that has been added below an existing entry in a backend set.
252   *
253   * @param  operationContext  The operation context for the operation that was
254   *                           processed.
255   * @param  backendSet        The backend set that currently holds the entry.
256   *
257   * @return  The backend set where the modified or added entry should be
258   *          relocated, or {@code null} if the entry should not be relocated.
259   */
260  public BackendSet selectRebalancingBackendSet(
261                                  final OperationContext operationContext,
262                                  final BackendSet backendSet)
263  {
264    // The default implementation is not do any rebalancing.
265    return null;
266  }
267
268
269
270  /**
271   * Determines whether this placement algorithm implements the
272   * {@link #selectRebalancingBackendSet} method to rebalance existing entries.
273   *
274   * @return  {@code true} if this placement algorithm supports re-balancing,
275   *          or {@code false} if not.
276   */
277  public boolean supportsRebalancing()
278  {
279    // The default implementation is that re-balancing is not supported.
280    return false;
281  }
282
283
284
285  /**
286   * Retrieves a string representation of this placement algorithm.
287   *
288   * @return  A string representation of this placement algorithm.
289   */
290  @Override()
291  public final String toString()
292  {
293    final StringBuilder buffer = new StringBuilder();
294    toString(buffer);
295    return buffer.toString();
296  }
297
298
299
300  /**
301   * Appends a string representation of this placement algorithm to the provided
302   * buffer.
303   *
304   * @param  buffer  The buffer to which the string representation should be
305   *                 appended.
306   */
307  public abstract void toString(final StringBuilder buffer);
308
309
310
311  /**
312   * {@inheritDoc}
313   */
314  public Map<List<String>,String> getExamplesArgumentSets()
315  {
316    return Collections.emptyMap();
317  }
318}