001 /*
002 * Copyright 2009-2014 UnboundID Corp.
003 * All Rights Reserved.
004 */
005 /*
006 * Copyright (C) 2009-2014 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 */
021 package com.unboundid.ldap.sdk;
022
023
024
025 import com.unboundid.util.Extensible;
026 import com.unboundid.util.ThreadSafety;
027 import com.unboundid.util.ThreadSafetyLevel;
028
029 import static com.unboundid.ldap.sdk.LDAPMessages.*;
030 import static com.unboundid.util.StaticUtils.*;
031
032
033
034 /**
035 * This class provides an API that may be used to determine whether connections
036 * associated with a connection pool are valid and suitable for use. It
037 * provides the ability to check the validity of a connection at the following
038 * times:
039 * <UL>
040 * <LI>Whenever a new connection is created for use in the pool, the
041 * {@link #ensureNewConnectionValid(LDAPConnection)} method will be called
042 * before making that connection available. The default implementation
043 * provided in this class does not perform any kind of processing, but
044 * subclasses may override this behavior if desired.</LI>
045 * <LI>Whenever a connection is checked out from the pool (including
046 * connections checked out internally for operations performed in the
047 * pool), the {@link #ensureConnectionValidForCheckout(LDAPConnection)}
048 * method will be called. The default implementation provided in this
049 * class does not perform any kind of processing, but subclasses may
050 * override this behavior if desired.</LI>
051 * <LI>Whenever a connection is released back to the pool (including
052 * connections checked out internally for operations performed in the
053 * pool), the {@link #ensureConnectionValidForRelease(LDAPConnection)}
054 * method will be called. The default implementation provided in this
055 * class does not perform any kind of processing, but subclasses may
056 * override this behavior if desired.</LI>
057 * <LI>The {@link #ensureConnectionValidForContinuedUse(LDAPConnection)}
058 * method will be invoked periodically by a background thread created by
059 * the connection pool to determine whether available connections within
060 * the pool are still valid. The default implementation provided in this
061 * class does not perform any kind of processing, but subclasses may
062 * override this behavior if desired.</LI>
063 * <LI>The {@link #ensureConnectionValidAfterException} method may be invoked
064 * if an exception is caught while processing an operation with a
065 * connection which is part of a connection pool. The default
066 * implementation provided in this class only examines the result code of
067 * the provided exception and uses the
068 * {@link ResultCode#isConnectionUsable(ResultCode)} method to make the
069 * determination, but subclasses may override this behavior if
070 * desired.</LI>
071 * </UL>
072 * Note that health check implementations should be designed so that they are
073 * suitable for use with connections having any authentication state. The
074 * {@link #ensureNewConnectionValid(LDAPConnection)} method will be invoked on
075 * unauthenticated connections, and the remaining health check methods will be
076 * invoked using whatever credentials are assigned to connections in the
077 * associated connection pool.
078 */
079 @Extensible()
080 @ThreadSafety(level=ThreadSafetyLevel.INTERFACE_THREADSAFE)
081 public class LDAPConnectionPoolHealthCheck
082 {
083 /**
084 * Creates a new instance of this LDAP connection pool health check.
085 */
086 public LDAPConnectionPoolHealthCheck()
087 {
088 // No implementation is required.
089 }
090
091
092
093 /**
094 * Performs any desired processing to determine whether the provided new
095 * connection is available to be checked out and used for processing
096 * operations. This method will be invoked by either {@link ServerSet} used
097 * by the connection pool (if it supports enhanced health checking) or by the
098 * connection pool itself at the time that a new connection is created.
099 *
100 * @param connection The connection to be examined.
101 *
102 * @throws LDAPException If a problem is detected which suggests that the
103 * provided connection is not suitable for use.
104 */
105 public void ensureNewConnectionValid(final LDAPConnection connection)
106 throws LDAPException
107 {
108 // No processing is performed in this default implementation.
109 }
110
111
112
113 /**
114 * Performs any desired processing to determine whether the provided
115 * connection is available to be checked out and used for processing
116 * operations. This method will be invoked by the
117 * {@link LDAPConnectionPool#getConnection()} method before handing out a
118 * connection. This method should return normally if the connection is
119 * believed to be valid, or should throw an {@code LDAPException} if a problem
120 * is detected.
121 *
122 * @param connection The connection to be examined.
123 *
124 * @throws LDAPException If a problem is detected which suggests that the
125 * provided connection is not suitable for use.
126 */
127 public void ensureConnectionValidForCheckout(final LDAPConnection connection)
128 throws LDAPException
129 {
130 // No processing is performed in this default implementation.
131 }
132
133
134
135 /**
136 * Performs any desired processing to determine whether the provided
137 * connection is valid and should be released back to the pool to be used for
138 * processing other operations. This method will be invoked by the
139 * {@link LDAPConnectionPool#releaseConnection(LDAPConnection)} method before
140 * making the connection available for use in processing other operations.
141 * This method should return normally if the connection is believed to be
142 * valid, or should throw an {@code LDAPException} if a problem is detected.
143 *
144 * @param connection The connection to be examined.
145 *
146 * @throws LDAPException If a problem is detected which suggests that the
147 * provided connection is not suitable for use.
148 */
149 public void ensureConnectionValidForRelease(final LDAPConnection connection)
150 throws LDAPException
151 {
152 // No processing is performed in this default implementation.
153 }
154
155
156
157 /**
158 * Performs any desired processing to determine whether the provided
159 * connection is valid and should continue to be made available for
160 * processing operations. This method will be periodically invoked by a
161 * background thread used to test availability of connections within the pool.
162 * This method should return normally if the connection is believed to be
163 * valid, or should throw an {@code LDAPException} if a problem is detected.
164 *
165 * @param connection The connection to be examined.
166 *
167 * @throws LDAPException If a problem is detected which suggests that the
168 * provided connection is not suitable for use.
169 */
170 public void ensureConnectionValidForContinuedUse(
171 final LDAPConnection connection)
172 throws LDAPException
173 {
174 // No processing is performed in this default implementation.
175 }
176
177
178
179 /**
180 * Indicates whether the provided connection may still be considered valid
181 * after an attempt to process an operation yielded the given exception. This
182 * method will be invoked by the
183 * {@link LDAPConnectionPool#releaseConnectionAfterException} method, and it
184 * may also be manually invoked by external callers if an exception is
185 * encountered while processing an operation on a connection checked out from
186 * the pool. It may make a determination based solely on the provided
187 * exception, or it may also attempt to use the provided connection to further
188 * test its validity. This method should return normally if the connection is
189 * believed to be valid, or should throw an {@code LDAPException} if a problem
190 * is detected.
191 *
192 * @param connection The connection to be examined.
193 * @param exception The exception that was caught while processing an
194 * operation on the connection.
195 *
196 * @throws LDAPException If a problem is detected which suggests that the
197 * provided connection is not suitable for use.
198 */
199 public void ensureConnectionValidAfterException(
200 final LDAPConnection connection,
201 final LDAPException exception)
202 throws LDAPException
203 {
204 if (! ResultCode.isConnectionUsable(exception.getResultCode()))
205 {
206 throw new LDAPException(ResultCode.SERVER_DOWN,
207 ERR_POOL_HEALTH_CHECK_CONN_INVALID_AFTER_EXCEPTION.get(
208 getExceptionMessage(exception)),
209 exception);
210 }
211 }
212
213
214
215 /**
216 * Retrieves a string representation of this LDAP connection pool health
217 * check.
218 *
219 * @return A string representation of this LDAP connection pool health check.
220 */
221 @Override()
222 public final String toString()
223 {
224 final StringBuilder buffer = new StringBuilder();
225 toString(buffer);
226 return buffer.toString();
227 }
228
229
230
231 /**
232 * Appends a string representation of this LDAP connection pool health check
233 * to the provided buffer.
234 *
235 * @param buffer The buffer to which the information should be appended.
236 */
237 public void toString(final StringBuilder buffer)
238 {
239 buffer.append("LDAPConnectionPoolHealthCheck()");
240 }
241 }