Create multiple connection pools dynamically __java

System scenario: The system relies on multiple databases. One of the database servers runs Oracle, and there are several machines running the Objectserver memory database. You need to dynamically create a connection pool because you can determine the number of machines from the deployment

Scenario: Oracle databases use C3P0 to manage connection pooling. Write another connection manager to dynamically create a memory database connection pool

Code: Simplified, only to post key code, remove log, exception handling, NULL check, etc.

Obejctserver connection pool, the number of domains in the system corresponds to the public 
class Dbconnectionpool
{
    private int checkedout;//The number of connections checked out by the class instance one by one

    private Vector<connection> freeconnections = new vector<connection> ()//Free connection number

    //return connection
    Public synchronized void freeconnection (Connection con, Object Lock)
    {
        freeconnections.addelement (con);
        this.checkedout--;
        Lock.notifyall ();
    }

    Get connection from Connection pool public
    Connection getconnection (Object Lock)
    {
        Connection con;
        while (con = fetchconnection ()) = = null)//Loop call Fetchconnection () method
        {            
            lock.wait (timeout);
            //If timed out, return null
        }
        Return con.
    }
}

Objectserver Connection Manager public class Dbconnectionmanager {private hashtable<string, dbconnectionpool> pools;//connection Pool collection, each OS domain has a connection pool private static final byte[] lock = new byte[0];//sync lock//return connection public void Freeco Nnection (String DomainName, Connection conn) {synchronized (lock) {DbConnection          
        Pool pool = (dbconnectionpool) pools.get (domainname);//Get the domain name corresponding to the connection pooling pool.freeconnection (conn, lock); }///Get the available connection from the machine public Connection getconnection (String domainname) {Synchro

            Nized (lock) {Dbconnectionpool pool = (dbconnectionpool) pools.get (domainname);           
            if (null!= pool)//connection pool already exists, use {return pool.getconnection (lock) directly;
                else {registernewconnectionpool (poolprovide);//Register New Connection pool Return getconnection (DoMainname);//Recursive Call} return null;
 }
    }
}