public static  void closeAll() throws Exception 
{
        //Get iterator to loop over all instances of this datasource.
        Iterator instanceIterator = instanceMap.entrySet().iterator();
        while (instanceIterator.hasNext()) {
            ((InstanceKeyDataSource)
                ((Map.Entry) instanceIterator.next()).getValue()).close();
        }
        instanceMap.clear();
}

Close all pools associated with this class.

 protected static final Object deserialize(byte[] data) throws ClassNotFoundException, IOException 
{
        ObjectInputStream in = null;
        try {
            in = new ObjectInputStream(new ByteArrayInputStream(data));
            return in.readObject();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException ex) {
                }
            }
        }
}

used to set some properties saved within a Reference

 abstract protected InstanceKeyDataSource getNewInstance(Reference ref) throws ClassNotFoundException, IOException
Creates an instance of the subclass and sets any properties
contained in the Reference.

 public Object getObjectInstance(Object refObj,
    Name name,
    Context context,
    Hashtable env) throws ClassNotFoundException, IOException 
{
        // The spec says to return null if we can't create an instance
        // of the reference
        Object obj = null;
        if (refObj instanceof Reference) {
            Reference ref = (Reference) refObj;
            if (isCorrectClass(ref.getClassName())) {
                RefAddr ra = ref.get("instanceKey");
                if (ra != null && ra.getContent() != null) {
                    // object was bound to jndi via Referenceable api.
                    obj = instanceMap.get(ra.getContent());
                }
                else
                {
                    // tomcat jndi creates a Reference out of server.xml
                    // < ResourceParam > configuration and passes it to an
                    // instance of the factory given in server.xml.
                    String key = null;
                    if (name != null)
                    {
                        key = name.toString();
                        obj = instanceMap.get(key);
                    }
                    if (obj == null)
                    {
                        InstanceKeyDataSource ds = getNewInstance(ref);
                        setCommonProperties(ref, ds);
                        obj = ds;
                        if (key != null)
                        {
                            instanceMap.put(key, ds);
                        }
                    }
                }
            }
        }
        return obj;
}

implements ObjectFactory to create an instance of SharedPoolDataSource or PerUserPoolDataSource

 abstract protected boolean isCorrectClass(String className)

 static synchronized String registerNewInstance(InstanceKeyDataSource ds) 
{
         
        int max = 0;
        Iterator i = instanceMap.keySet().iterator();
        while (i.hasNext()) {
            Object obj = i.next();
            if (obj instanceof String)
            {
                try {
                    max = Math.max(max, Integer.valueOf((String)obj).intValue());
                }
                catch (NumberFormatException e) {
                    // no sweat, ignore those keys
                }
            }
        }
        String instanceKey = String.valueOf(max + 1);
        // put a placeholder here for now, so other instances will not
        // take our key.  we will replace with a pool when ready.
        instanceMap.put(instanceKey, ds);
        return instanceKey;
}

 static  void removeInstance(String key) 
{
        instanceMap.remove(key);
}