LdapConnectionPool.java

/*
 ************************************************************************
 *******************  CANADIAN ASTRONOMY DATA CENTRE  *******************
 **************  CENTRE CANADIEN DE DONNÉES ASTRONOMIQUES  **************
 *
 *  (c) 2015.                            (c) 2015.
 *  Government of Canada                 Gouvernement du Canada
 *  National Research Council            Conseil national de recherches
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package ca.nrc.cadc.ac.server.ldap;

import org.apache.log4j.Logger;
import org.seleniumhq.jetty7.util.log.Log;

import ca.nrc.cadc.ac.server.ldap.LdapConfig.LdapPool;
import ca.nrc.cadc.ac.server.ldap.LdapConfig.PoolPolicy;
import ca.nrc.cadc.profiler.Profiler;

import com.unboundid.ldap.sdk.FewestConnectionsServerSet;
import com.unboundid.ldap.sdk.LDAPConnection;
import com.unboundid.ldap.sdk.LDAPConnectionPool;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.LDAPReadWriteConnectionPool;
import com.unboundid.ldap.sdk.RoundRobinServerSet;
import com.unboundid.ldap.sdk.ServerSet;
import com.unboundid.ldap.sdk.SimpleBindRequest;

/**
 * This object is designed to be shared between the DAO classes
 * for access to LDAP.  There should only be a single instance.
 * It contains a connection pool object from the UnboundID library.
 *
 * @author majorb
 */
public class LdapConnectionPool
{
    private static final Logger logger = Logger.getLogger(LdapUserPersistence.class);

    private static final int POOL_CHECK_INTERVAL_MILLESCONDS = 10000; // 10 seconds

    Profiler profiler = new Profiler(LdapPersistence.class);

    protected LdapConfig currentConfig;
    private LDAPReadWriteConnectionPool pool;
    private Object poolMonitor = new Object();

    private long lastPoolCheck = System.currentTimeMillis();

    LdapConnectionPool()
    {
        this.currentConfig = LdapConfig.getLdapConfig();
        pool = createPool(currentConfig);
        profiler.checkpoint("Create pool");
    }

    protected LDAPConnection getReadOnlyConnection() throws LDAPException
    {
        synchronized (poolMonitor)
        {
            poolCheck();
            LDAPConnection conn = pool.getReadConnection();
            profiler.checkpoint("get read write connection");
            return conn;
        }
    }

    protected LDAPConnection getReadWriteConnection() throws LDAPException
    {
        synchronized (poolMonitor)
        {
            poolCheck();
            LDAPConnection conn = pool.getWriteConnection();
            profiler.checkpoint("get read write connection");
            return conn;
        }
    }

    protected void releaseReadOnlyConnection(LDAPConnection conn)
    {
        synchronized (poolMonitor)
        {
            pool.releaseReadConnection(conn);
        }
    }

    protected void releaseReadWriteConnection(LDAPConnection conn)
    {
        synchronized (poolMonitor)
        {
            pool.releaseWriteConnection(conn);
        }
    }

    protected void shutdown()
    {
        logger.debug("Shutting down pool");
        pool.close();
        profiler.checkpoint("Shutdown pool");
    }

    private void poolCheck()
    {
        if (timeToCheckPool())
        {
            synchronized (poolMonitor)
            {
                if (timeToCheckPool())
                {
                    // check to see if the configuration has changed
                    logger.debug("checking for ldap config change");
                    LdapConfig newConfig = LdapConfig.getLdapConfig();
                    if (!newConfig.equals(currentConfig))
                    {
                        logger.debug("Detected ldap configuration change, rebuilding pools");
                        this.currentConfig = newConfig;

                        pool.close();
                        profiler.checkpoint("Close old pool");

                        pool = createPool(currentConfig);
                        profiler.checkpoint("Rebuild pool");
                    }
                    lastPoolCheck = System.currentTimeMillis();
                }
            }
        }
    }

    private boolean timeToCheckPool()
    {
        return System.currentTimeMillis() - lastPoolCheck > POOL_CHECK_INTERVAL_MILLESCONDS;
    }

    static LDAPReadWriteConnectionPool createPool(LdapConfig config)
    {
        LDAPConnectionPool ro = createPool(config.getReadOnlyPool(), config);
        LDAPConnectionPool rw = createPool(config.getReadOnlyPool(), config);
        LDAPReadWriteConnectionPool pool = new LDAPReadWriteConnectionPool(ro, rw);
        return pool;
    }

    private static LDAPConnectionPool createPool(LdapPool pool, LdapConfig config)
    {
        try
        {
            logger.debug("LDAP Config: " + config);
            String[] hosts = pool.getServers().toArray(new String[0]);
            int[] ports = new int[pool.getServers().size()];
            for (int i=0; i<pool.getServers().size(); i++)
            {
                ports[i] = config.getPort();
            }

            ServerSet serverSet = null;
            if (pool.getPolicy().equals(PoolPolicy.roundRobin))
            {
                serverSet = new RoundRobinServerSet(hosts, ports, LdapDAO.getSocketFactory(config));
            }
            else if (pool.getPolicy().equals(PoolPolicy.fewestConnections))
            {
                serverSet = new FewestConnectionsServerSet(hosts, ports, LdapDAO.getSocketFactory(config));
            }
            else
            {
                throw new IllegalStateException("Unconfigured pool policy: " + pool.getPolicy());
            }

            SimpleBindRequest bindRequest = new SimpleBindRequest(config.getAdminUserDN(), config.getAdminPasswd());
            LDAPConnectionPool connectionPool = new LDAPConnectionPool(
                serverSet, bindRequest, pool.getInitSize(), pool.getMaxSize());

            return connectionPool;
        }
        catch (Exception e)
        {
            logger.error("Failed to create connection pool", e);
            throw new IllegalStateException(e);
        }
    }

}