Package com.unboundid.ldap.sdk

Class FewestConnectionsServerSet

  • @NotMutable
@ThreadSafety(level=COMPLETELY_THREADSAFE)
public final class FewestConnectionsServerSet
extends ServerSet
    This class provides a server set implementation that will establish a connection to the server with the fewest established connections previously created by the same server set instance. If there are multiple servers that share the fewest number of established connections, the first one in the list will be chosen. If a server is unavailable when an attempt is made to establish a connection to it, then the connection will be established to the available server with the next fewest number of established connections.

    This server set implementation has the ability to maintain a temporary blacklist of servers that have been recently found to be unavailable or unsuitable for use. If an attempt to establish or authenticate a connection fails, if post-connect processing fails for that connection, or if health checking indicates that the connection is not suitable, then that server may be placed on the blacklist so that it will only be tried as a last resort after all non-blacklisted servers have been attempted. The blacklist will be checked at regular intervals to determine whether a server should be re-instated to availability.

    Note that this server set implementation is primarily intended for use with connection pools, but is also suitable for cases in which standalone connections are created as long as there will not be any attempt to close the connections when they are re-established. It is not suitable for use in connections that may be re-established one or more times after being closed.

    Example

    The following example demonstrates the process for creating a fewest connections server set that may be used to establish connections to either of two servers. 
     // Create arrays with the addresses and ports of the directory server
 // instances.
 String[] addresses =
 {
   server1Address,
   server2Address
 };
 int[] ports =
 {
   server1Port,
   server2Port
 };

 // Create the server set using the address and port arrays.
 FewestConnectionsServerSet fewestConnectionsSet =
      new FewestConnectionsServerSet(addresses, ports);

 // Verify that we can establish a single connection using the server set.
 LDAPConnection connection = fewestConnectionsSet.getConnection();
 RootDSE rootDSEFromConnection = connection.getRootDSE();
 connection.close();

 // Verify that we can establish a connection pool using the server set.
 SimpleBindRequest bindRequest =
      new SimpleBindRequest("uid=pool.user,dc=example,dc=com", "password");
 LDAPConnectionPool pool =
      new LDAPConnectionPool(fewestConnectionsSet, bindRequest, 10);
 RootDSE rootDSEFromPool = pool.getRootDSE();
 pool.close();

    • Constructor Summary

      Constructors 
      Constructor Description
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports, LDAPConnectionOptions connectionOptions)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports, javax.net.SocketFactory socketFactory)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports, javax.net.SocketFactory socketFactory, LDAPConnectionOptions connectionOptions)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports, javax.net.SocketFactory socketFactory, LDAPConnectionOptions connectionOptions, BindRequest bindRequest, PostConnectProcessor postConnectProcessor)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.
      FewestConnectionsServerSet​(java.lang.String[] addresses, int[] ports, javax.net.SocketFactory socketFactory, LDAPConnectionOptions connectionOptions, BindRequest bindRequest, PostConnectProcessor postConnectProcessor, long blacklistCheckIntervalMillis)
      Creates a new fewest connections server set with the specified set of directory server addresses and port numbers.

    • Constructor Detail

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the default socket factory provided by the JVM to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports,
                                  LDAPConnectionOptions connectionOptions)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the default socket factory provided by the JVM to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.
        connectionOptions - The set of connection options to use for the underlying connections.

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports,
                                  javax.net.SocketFactory socketFactory)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the provided socket factory to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.
        socketFactory - The socket factory to use to create the underlying connections.

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports,
                                  javax.net.SocketFactory socketFactory,
                                  LDAPConnectionOptions connectionOptions)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the provided socket factory to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.
        socketFactory - The socket factory to use to create the underlying connections.
        connectionOptions - The set of connection options to use for the underlying connections.

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports,
                                  javax.net.SocketFactory socketFactory,
                                  LDAPConnectionOptions connectionOptions,
                                  BindRequest bindRequest,
                                  PostConnectProcessor postConnectProcessor)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the provided socket factory to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.
        socketFactory - The socket factory to use to create the underlying connections.
        connectionOptions - The set of connection options to use for the underlying connections.
        bindRequest - The bind request that should be used to authenticate newly established connections. It may be null if this server set should not perform any authentication.
        postConnectProcessor - The post-connect processor that should be invoked on newly established connections. It may be null if this server set should not perform any post-connect processing.

      • FewestConnectionsServerSet

        public FewestConnectionsServerSet​(java.lang.String[] addresses,
                                  int[] ports,
                                  javax.net.SocketFactory socketFactory,
                                  LDAPConnectionOptions connectionOptions,
                                  BindRequest bindRequest,
                                  PostConnectProcessor postConnectProcessor,
                                  long blacklistCheckIntervalMillis)
        Creates a new fewest connections server set with the specified set of directory server addresses and port numbers. It will use the provided socket factory to create the underlying sockets.
        Parameters:
        addresses - The addresses of the directory servers to which the connections should be established. It must not be null or empty.
        ports - The ports of the directory servers to which the connections should be established. It must not be null, and it must have the same number of elements as the addresses array. The order of elements in the addresses array must correspond to the order of elements in the ports array.
        socketFactory - The socket factory to use to create the underlying connections.
        connectionOptions - The set of connection options to use for the underlying connections.
        bindRequest - The bind request that should be used to authenticate newly established connections. It may be null if this server set should not perform any authentication.
        postConnectProcessor - The post-connect processor that should be invoked on newly established connections. It may be null if this server set should not perform any post-connect processing.
        blacklistCheckIntervalMillis - The length of time in milliseconds between checks of servers on the blacklist to determine whether they are once again suitable for use. A value that is less than or equal to zero indicates that no blacklist should be maintained.

    • Method Detail

      • getAddresses

        public java.lang.String[] getAddresses()
        Retrieves the addresses of the directory servers to which the connections should be established.
        Returns:
        The addresses of the directory servers to which the connections should be established.

      • getPorts

        public int[] getPorts()
        Retrieves the ports of the directory servers to which the connections should be established.
        Returns:
        The ports of the directory servers to which the connections should be established.

      • getSocketFactory

        public javax.net.SocketFactory getSocketFactory()
        Retrieves the socket factory that will be used to establish connections.
        Returns:
        The socket factory that will be used to establish connections.

      • getConnectionOptions

        public LDAPConnectionOptions getConnectionOptions()
        Retrieves the set of connection options that will be used for underlying connections.
        Returns:
        The set of connection options that will be used for underlying connections.

      • includesAuthentication

        public boolean includesAuthentication()
        Indicates whether connections created by this server set will be authenticated.
        Overrides:
        includesAuthentication in class ServerSet
        Returns:
        true if connections created by this server set will be authenticated, or false if not.

      • includesPostConnectProcessing

        public boolean includesPostConnectProcessing()
        Indicates whether connections created by this server set will have post-connect processing performed.
        Overrides:
        includesPostConnectProcessing in class ServerSet
        Returns:
        true if connections created by this server set will have post-connect processing performed, or false if not.

      • getConnection

        public LDAPConnection getConnection​(LDAPConnectionPoolHealthCheck healthCheck)
                             throws LDAPException
        Attempts to establish a connection to one of the directory servers in this server set, using the provided health check to further validate the connection. The connection that is returned must be established. The ServerSet.includesAuthentication() must return true if and only if the connection will also be authenticated, and the ServerSet.includesPostConnectProcessing() method must return true if and only if pre-authentication and post-authentication post-connect processing will have been performed. The caller may determine the server to which the connection is established using the LDAPConnection.getConnectedAddress() and LDAPConnection.getConnectedPort() methods.
        Overrides:
        getConnection in class ServerSet
        Parameters:
        healthCheck - The health check to use to verify the health of the newly-created connection. It may be null if no additional health check should be performed. If it is non-null and this server set performs authentication, then the health check's ensureConnectionValidAfterAuthentication method will be invoked immediately after the bind operation is processed (regardless of whether the bind was successful or not). And regardless of whether this server set performs authentication, the health check's ensureNewConnectionValid method must be invoked on the connection to ensure that it is valid immediately before it is returned.
        Returns:
        An LDAPConnection object that is established to one of the servers in this server set.
        Throws:
        LDAPException - If it is not possible to establish a connection to any of the servers in this server set.

      • handleConnectionClosed

        protected void handleConnectionClosed​(LDAPConnection connection,
                                      java.lang.String host,
                                      int port,
                                      DisconnectType disconnectType,
                                      java.lang.String message,
                                      java.lang.Throwable cause)
        Performs any processing that may be required when the provided connection is closed. This will only be invoked for connections created by this server set, and only if the ServerSet.associateConnectionWithThisServerSet(com.unboundid.ldap.sdk.LDAPConnection) method was called on the connection when it was created by this server set.
        Overrides:
        handleConnectionClosed in class ServerSet
        Parameters:
        connection - The connection that has been closed.
        host - The address of the server to which the connection had been established.
        port - The port of the server to which the connection had been established.
        disconnectType - The disconnect type, which provides general information about the nature of the disconnect.
        message - A message that may be associated with the disconnect. It may be null if no message is available.
        cause - A Throwable that was caught and triggered the disconnect. It may be null if the disconnect was not triggered by a client-side exception or error.

      • toString

        public void toString​(java.lang.StringBuilder buffer)
        Appends a string representation of this server set to the provided buffer.
        Overrides:
        toString in class ServerSet
        Parameters:
        buffer - The buffer to which the string representation should be appended.