001 /*
002 * Copyright 2008-2014 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 */
021 package com.unboundid.ldap.sdk;
022
023
024
025
026 import static com.unboundid.util.Debug.*;
027
028
029
030 /**
031 * This class defines an API that can be used to select between multiple
032 * directory servers when establishing a connection. Implementations are free
033 * to use any kind of logic that they desire when selecting the server to which
034 * the connection is to be established. They may also support the use of
035 * health checks to determine whether the created connections are suitable for
036 * use.
037 * <BR><BR>
038 * Implementations MUST be threadsafe to allow for multiple concurrent attempts
039 * to establish new connections.
040 */
041 public abstract class ServerSet
042 {
043 /**
044 * Creates a new instance of this server set.
045 */
046 protected ServerSet()
047 {
048 // No implementation is required.
049 }
050
051
052
053 /**
054 * Attempts to establish a connection to one of the directory servers in this
055 * server set. The connection should be established but unauthenticated. The
056 * caller may determine the server to which the connection is established
057 * using the {@code LDAPConnection#getConnectedAddress} and
058 * {@code LDAPConnection#getConnectedPort} methods.
059 *
060 * @return An {@code LDAPConnection} object that is established to one of the
061 * servers in this server set.
062 *
063 * @throws LDAPException If it is not possible to establish a connection to
064 * any of the servers in this server set.
065 */
066 public abstract LDAPConnection getConnection()
067 throws LDAPException;
068
069
070
071 /**
072 * Attempts to establish a connection to one of the directory servers in this
073 * server set, using the provided health check to further validate the
074 * connection. The connection should be established but unauthenticated.
075 * The caller may determine the server to which the connection is established
076 * using the {@code LDAPConnection#getConnectedAddress} and
077 * {@code LDAPConnection#getConnectedPort} methods.
078 *
079 * @param healthCheck The health check to use to make the determination, or
080 * {@code null} if no additional health check should be
081 * performed.
082 *
083 * @return An {@code LDAPConnection} object that is established to one of the
084 * servers in this server set.
085 *
086 * @throws LDAPException If it is not possible to establish a connection to
087 * any of the servers in this server set.
088 */
089 public LDAPConnection getConnection(
090 final LDAPConnectionPoolHealthCheck healthCheck)
091 throws LDAPException
092 {
093 final LDAPConnection c = getConnection();
094
095 if (healthCheck != null)
096 {
097 try
098 {
099 healthCheck.ensureNewConnectionValid(c);
100 }
101 catch (LDAPException le)
102 {
103 debugException(le);
104 c.close();
105 throw le;
106 }
107 }
108
109 return c;
110 }
111
112
113
114 /**
115 * Retrieves a string representation of this server set.
116 *
117 * @return A string representation of this server set.
118 */
119 @Override()
120 public String toString()
121 {
122 final StringBuilder buffer = new StringBuilder();
123 toString(buffer);
124 return buffer.toString();
125 }
126
127
128
129 /**
130 * Appends a string representation of this server set to the provided buffer.
131 *
132 * @param buffer The buffer to which the string representation should be
133 * appended.
134 */
135 public void toString(final StringBuilder buffer)
136 {
137 buffer.append("ServerSet(className=");
138 buffer.append(getClass().getName());
139 buffer.append(')');
140 }
141 }