1. The Internet Communications Engine (Ice)
ZeroC’s
object-oriented distributed middleware platform
Presented by Michael Borosh
UChicago MPCS QuickTalk

2. The Internet Communications Engine (Ice)
Core product of ZeroC (small private company based in Jupiter, FL; founded in 2002; partial client list above)
Available under GPL and commercial license

3. Context: CORBA
Common Object Request Broker Architecture (CORBA)—middleware that enables communication between software components (which can be written in multiple computer languages and running on multiple computers). Broker design pattern (distributed system with decoupled components interacting by remote service invocations).
Standard, defined by the Object Management Group (OMG, also associated with UML)
Provides RPC invocation through a middle layer called the ORB
Interface Definition Language (IDL)—mapping to Ada, C, C++, C++11, Lisp, Ruby, Smalltalk, Java, COBOL, PL/I, Java
Michi Henning Essay: The Rise and Fall of Corba (

4. How Ice Differs From CORBA
No “Design By Committee”
Specification Language for Ice (SLICE) vs IDL
Language Mappings: C++, Java, Python, Ruby, PHP, .NET
Working with databases: SLICE can describe the state of persistent Ice objects
Working with C++: C++ Mapping Based on STL
No “Any” Type (something extensively used in CORBA)
Asynchronous Message Invocation (supported by few CORBA products)
Partial list. Source:

5. Ice Advantages Disadvantages
Performance (
Ease of use
Forums/Support
Documentation
Disadvantages
Lack of standardization
Price

6. Ice Features
IceStorm—service to efficiently distribute messages that have one source but many destinations (pub-sub); event subscriptions can be made persistent and there are tools for managing dysfunctional clients
IceFIX—integrates the FIX protocol into Ice (

7. Installation—Ice 3.5.1 Download at: http://zeroc.com/download.html
Working with AWS ec2, I installed on Ubuntu and with minimal success before trying Red Hat Enterprise Linux 6, which I can recommend
Note: uses Third-Party Frameworks including Qt that have to be compatibly installed and configured. Also, I had to separately install php-zeroc-ice package.
Nice ZeroC supplied Demo—Chat Application (

8. Chat Demo: Requirements
Client/Server architecture (clients are active entities that send requests while servers are passive entities that respond to requests)
Minimal or no server administration
Traffic between client/server must be secure
Must work with firewalls
Clients may be implemented in various languages
Minimal network traffic as clients may have bandwidth constraints
Source:

9. Chat Demo: Push Model
Push Model: Reversal of normal roles. Clients provide an Ice object with an operation that the chat server invokes (asynchronously) to deliver messages to clients.
// Slice
module Chat {
interface ChatRoomCallback // Implemented by clients
void init(Ice::StringSeq users);
//server invokes init when client first connects to the chat room, users informs clients of currently connected users
void join(long timestamp, string name);
void leave(long timestamp, string name);
void send(long timestamp, string name, string message); //server invokes send when a client sends a message };
Source:

10. Chat Demo: Glacier2 Router
Bidirectional connections—allows requests to flow in both directions, without regard to which side opened the connection. Server can invoke methods without having to open up a new connection from server to client.
Source:

11. Glacier2::SessionPrx
ChatSessionManagerI::create( const string& name, const Glacier2::SessionControlPrx& sessionControl, const Ice::Current& c)
{ string vname;
try {
vname = validateName(name);
_chatRoom->reserve(vname);
} …
Glacier2::SessionPrx proxy;
ChatSessionIPtr session = new ChatSessionI(_chatRoom, vname, _trace, _logger);
proxy = Glacier2::SessionPrx::uncheckedCast( c.adapter -> addWithUUID(session));
Ice::IdentitySeq ids;
ids.push_back(proxy->ice_getIdentity());
sessionControl->identities()->add(ids);
if(_trace) {
ostringstream os; os<< "Push session created for user '" << vname << "'.";
_logger->trace("info", os.str()); }
return proxy; }
Session example

12. Code Sample Ice::Long Send Example
ChatRoom::send(const string& name, const string& message) {
IceUtil::Mutex::Lock sync(_mutex);
IceUtil::Int64 timestamp = IceUtil::Time::now().toMilliSeconds();
PollingChat::MessageEventPtr e = new PollingChat::MessageEvent(timestamp, name, message);
for(ChatRoomCallbackMap::iterator q = _members.begin(); q != _members.end(); ++q)
q->second->send(e); }
if(_trace)
ostringstream os;
os << "User '" << name << "' sent a message to the chat room."; _logger->trace("info", os.str());
return timestamp;
Send Example
Code Sample
Source::

13. Overall Architecture

14. Training / Resources Documentation
Manual [3000+ Pages] (
Training (
C++ Deck [300+ Slides] (
C++ Student Workbook [400+ Slides] (
Chat Demo
Source (
Technical Articles (

15. Questions?