Add meaningful exception when trying to send message exchange before endpoint activation

A message exchange in PollingEndpoint.java's Poll method cannot be sent because the endpoint has yet to have been activated at that point. A meaningful exception would help.

This example code is an endpoint class derived from PollingEndpoint that gives a null pointer exception which isn't very meaningful.

public void poll() throws Exception

{ invokeIdentityService(); }

private boolean invokeIdentityService() throws MessagingException {

ComponentContext ctx = getServiceUnit().getComponent().getComponentContext();

QName identityService = new QName("http://servicemix.apache.org/servicemanagerassembly",
"httpService");

InOut identityExchange = exchangeFactory.createInOutExchange();

configureTarget("Identity Service", identityExchange, ctx,
null, identityService, "soap", "");

NormalizedMessage in = identityExchange.createMessage();
in.setContent(new StringSource("Testing"));
identityExchange.setInMessage(in);

sendSync(identityExchange);

NormalizedMessage out = identityExchange.getOutMessage();
boolean login = false;
if (out != null)

{ //login = support.parseIdentityOutMessage(out.getContent()); }

else

{ // TODO: how should we handle faults }

done(identityExchange);

return login;
}

public void configureTarget(String serviceDesc, MessageExchange
exchange, ComponentContext context, QName _interface, QName service,
String endpoint, String uri) throws MessagingException {

if (_interface == null && service == null && uri == null)

{ throw new MessagingException(serviceDesc + ": interface, service or uri should be specified"); }

/*if (uri != null)

{ URIResolver.configureExchange(exchange, context, uri); }

*/
if (_interface != null)

{ exchange.setInterfaceName(_interface); }

if (service != null) {
exchange.setService(service);
if (endpoint != null)

{ ServiceEndpoint se = context.getEndpoint(service, endpoint); exchange.setEndpoint(se); }

}
}