001 /*
002 * Copyright 2008-2016 UnboundID Corp.
003 * All Rights Reserved.
004 */
005 /*
006 * Copyright (C) 2008-2016 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.util.Debug.*;
030
031
032
033 /**
034 * This class defines an API that can be used to select between multiple
035 * directory servers when establishing a connection. Implementations are free
036 * to use any kind of logic that they desire when selecting the server to which
037 * the connection is to be established. They may also support the use of
038 * health checks to determine whether the created connections are suitable for
039 * use.
040 * <BR><BR>
041 * Implementations MUST be threadsafe to allow for multiple concurrent attempts
042 * to establish new connections.
043 */
044 @Extensible()
045 @ThreadSafety(level=ThreadSafetyLevel.INTERFACE_THREADSAFE)
046 public abstract class ServerSet
047 {
048 /**
049 * Creates a new instance of this server set.
050 */
051 protected ServerSet()
052 {
053 // No implementation is required.
054 }
055
056
057
058 /**
059 * Attempts to establish a connection to one of the directory servers in this
060 * server set. The connection should be established but unauthenticated. The
061 * caller may determine the server to which the connection is established
062 * using the {@link LDAPConnection#getConnectedAddress} and
063 * {@link LDAPConnection#getConnectedPort} methods.
064 *
065 * @return An {@code LDAPConnection} object that is established to one of the
066 * servers in this server set.
067 *
068 * @throws LDAPException If it is not possible to establish a connection to
069 * any of the servers in this server set.
070 */
071 public abstract LDAPConnection getConnection()
072 throws LDAPException;
073
074
075
076 /**
077 * Attempts to establish a connection to one of the directory servers in this
078 * server set, using the provided health check to further validate the
079 * connection. The connection should be established but unauthenticated.
080 * The caller may determine the server to which the connection is established
081 * using the {@link LDAPConnection#getConnectedAddress} and
082 * {@link LDAPConnection#getConnectedPort} methods.
083 *
084 * @param healthCheck The health check to use to make the determination, or
085 * {@code null} if no additional health check should be
086 * performed.
087 *
088 * @return An {@code LDAPConnection} object that is established to one of the
089 * servers in this server set.
090 *
091 * @throws LDAPException If it is not possible to establish a connection to
092 * any of the servers in this server set.
093 */
094 public LDAPConnection getConnection(
095 final LDAPConnectionPoolHealthCheck healthCheck)
096 throws LDAPException
097 {
098 final LDAPConnection c = getConnection();
099
100 if (healthCheck != null)
101 {
102 try
103 {
104 healthCheck.ensureNewConnectionValid(c);
105 }
106 catch (LDAPException le)
107 {
108 debugException(le);
109 c.close();
110 throw le;
111 }
112 }
113
114 return c;
115 }
116
117
118
119 /**
120 * Retrieves a string representation of this server set.
121 *
122 * @return A string representation of this server set.
123 */
124 @Override()
125 public String toString()
126 {
127 final StringBuilder buffer = new StringBuilder();
128 toString(buffer);
129 return buffer.toString();
130 }
131
132
133
134 /**
135 * Appends a string representation of this server set to the provided buffer.
136 *
137 * @param buffer The buffer to which the string representation should be
138 * appended.
139 */
140 public void toString(final StringBuilder buffer)
141 {
142 buffer.append("ServerSet(className=");
143 buffer.append(getClass().getName());
144 buffer.append(')');
145 }
146 }