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 }