// SMSLib for Java v3
// A Java API library for sending and receiving SMS via a GSM modem
// or other supported gateways.
// Web Site: http://www.smslib.org
//
// Copyright (C) 2002-2008, Thanasis Delenikas, Athens/GREECE.
// SMSLib is distributed under the terms of the Apache License version 2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.smslib.v3;
import java.util.ArrayList;
import java.util.List;
/**
* Base message routing class. Service owns instance of Router (or its
* subclass), and uses its member functions to designate gateway(s) to send
* particular outgoing message. It is allowed that router designates more than
* modem to send message. It is responsibility of Router to decide which gateway
* will send the message. Custom routing rules are possible by creating
* subclass.
*
* @author Tomek Cejner
*/
public class Router
{
/** List of candidate gateways */
@SuppressWarnings("unchecked")
protected List candidates;
/** List of gateways that are allowed to send message */
@SuppressWarnings("unchecked")
protected List allowed;
protected Service srv;
@SuppressWarnings("unchecked")
public Router(Service srv)
{
candidates = new ArrayList();
allowed = new ArrayList();
this.srv = srv;
}
/**
* Perform early-stage routing, pick gateways that meet minimal requirements
* to send message (for example are set to handle outbound messages).
*
* @param msg
* Message to be routed
*/
@SuppressWarnings("unchecked")
protected void preroute(OutboundMessage msg)
{
for (int i = 0, n = srv.getGatewayList().size(); i < n; i ++)
{
AGateway gw = (AGateway) srv.getGatewayList().get(i);
if (gw.isOutbound()) candidates.add(gw);
}
}
/**
* Heart of routing & load balancing mechanism
*
* @param msg
*/
protected AGateway route(OutboundMessage msg)
{
AGateway gw;
beginRouting();
preroute(msg);
// perform custom routing
customRouting(msg);
// check if there are any gateways designated to send?
if (allowed.size() > 0)
{
gw = srv.getLoadBalancer().balance(msg, allowed);
}
else
{
msg.setFailureCause(FailureCauses.NO_ROUTE);
msg.setMessageStatus(MessageStatuses.FAILED);
gw = null;
}
// finish
finishRouting();
return gw;
}
/**
* Place for custom routing performed by specialized subclass. A "positive"
* approach is taken. Method has to copy references to gateways from
* <code>candidates</code> list to <code>allowed</code>. So, default
* behavior is to copy all references. Another possibility is to take
* "negative" approach, where method should delete unwanted gateways from
* list. This approach was found difficult to use at this time.
*
* @param msg
* Message to be routed
*/
@SuppressWarnings("unchecked")
public void customRouting(OutboundMessage msg)
{
if ((msg.getGatewayId().length() == 0) || (msg.getGatewayId().equals("*"))) allowed.addAll(candidates);
else
{
if (srv.findGateway(msg.getGatewayId()) != null) allowed.add(srv.findGateway(msg.getGatewayId()));
}
}
/**
* Prepare internal data for routing (clean internal data structures). Must
* be called when new message is routed.
*/
protected final void beginRouting()
{
candidates.clear();
allowed.clear();
}
/**
* Cleanup after routing
*/
protected final void finishRouting()
{
candidates.clear();
allowed.clear();
}
}