ICE MINI GUIDE

Getting start

Ady@SOHU 2012/02/28

What is ICE?

The Internet Communications Engine

An object-oriented distributed middleware platform.

ICE Content

object-oriented RPC mechanism

language-neutral specification language (Slice)

language mappings for various languages

support for different transports (TCP, SSL, UDP) with highly-efficient protocol

external services (server activation, firewall traversal, etc.)

integrated persistence (Freeze)

threading support

Client and Server Structure

Server ApplicationClient Application

Generated Code

Proxy

Code

Network

Ice API

Client Ice Core

Object

AdapterIce API

Server Ice Core

Skeleton

Ice API

What is slice?

language-independent types

a compiler creates language-specific source

code

only type definitions without statements

define operations and exchange type defined

Java Programming Model

Basic Slice Types

Type Range of Mapped Type Size of Mapped Type

bool false or true ≥ 1 bits

byte -128-127 or 0-255 ≥ 8 bits

short -215 to 215-1 ≥ 16 bits

int -231 to 231-1 ≥ 32 bits

long -263 to 263-1 ≥ 64 bits

float IEEE single-precision ≥ 32 bits

double IEEE double-precision ≥ 64 bits

string Unicode (UTF-8 for java) Variable-length

Enumerations

enum CounterType {

BLOG,

ALBUM,

FEED,

GUEST

};

Rules

• Like Java Enum

• Cannot specify the value

• Empty enumerations are illegal

Structures

struct TimeOfDay {

short hour; // 0-23

short minute; // 0-59

short second; // 0-59

};

Sequences

sequences<AccountIndex> AccountIndexList;

Default Type(Arrays): AccountIndex[]

Define other types (ArrayList/LinkedList)

["java:type:java.util.ArrayList"]

sequences<AccountIndex> AccountIndexList;

Dictionaries

dictionary<string,string> AccountCacheMap;

dictionary<string,AccountCacheMap> AccountCacheMapMap;

Default type: java.util.HashMap

The key rule:

An integral type (bool, byte, short, int, long, enum) or string

A structure containing only members of integral type or type string

Interfaces

dictionary<string,string> AccountCacheMap;

dictionary<string,AccountCacheMap> AccountCacheMapMap;

["java:type:java.util.ArrayList"] sequence<string> StringList;

interface AccountCacheService {

AccountCacheMap get(string passport);

AccountCacheMapMap gets(StringList passports);

};

Interfaces Operations And Parameters

rules

an operation name

a return type (or void if none)

zero or more parameters

an optional exception specification

operation cannot be overloaded

A SIMPLE DEMO

Step 1: write a slice file

module sce{

module demo{

interface CounterService{

int incr();

int decr();

int get();

void set(int num);

};

};

};

Step 2: slice2java

slice2java demo.ice

C:\Users\xylz\workspace\sce-demo>ll sce-demo

-rw-rw-rw- 1 user group 1089 Feb 28 16:34 Callback_CounterService_decr.java

-rw-rw-rw- 1 user group 1086 Feb 28 16:34 Callback_CounterService_get.java

-rw-rw-rw- 1 user group 1089 Feb 28 16:34 Callback_CounterService_incr.java

-rw-rw-rw- 1 user group 639 Feb 28 16:34 Callback_CounterService_set.java

-rw-rw-rw- 1 user group 697 Feb 28 16:34 CounterService.java

-rw-rw-rw- 1 user group 1149 Feb 28 16:34 CounterServiceHolder.java

-rw-rw-rw- 1 user group 3112 Feb 28 16:34 CounterServicePrx.java

-rw-rw-rw- 1 user group 17744 Feb 28 16:34 CounterServicePrxHelper.java

-rw-rw-rw- 1 user group 808 Feb 28 16:34 CounterServicePrxHolder.java

-rw-rw-rw- 1 user group 1034 Feb 28 16:34 _CounterServiceDel.java

-rw-rw-rw- 1 user group 7998 Feb 28 16:34 _CounterServiceDelD.java

-rw-rw-rw- 1 user group 5642 Feb 28 16:34 _CounterServiceDelM.java

-rw-rw-rw- 1 user group 6210 Feb 28 16:34 _CounterServiceDisp.java

-rw-rw-rw- 1 user group 769 Feb 28 16:34 _CounterServiceOperations.java

-rw-rw-rw- 1 user group 687 Feb 28 16:34 _CounterServiceOperationsNC.java

Step 3: write a server

package sce.demo.server;

import java.util.concurrent.atomic.AtomicInteger;

import Ice.Current;

import sce.demo._CounterServiceDisp;

public class CounterServiceI extends _CounterServiceDisp {

final AtomicInteger counter = new AtomicInteger(0);

public int incr(Current __current) { return counter.incrementAndGet(); }

public int decr(Current __current) {return counter.decrementAndGet();}

public int get(Current __current) {return counter.get();}

public void set(int num, Current __current) {counter.set(num); }

}

Step 4: start the server package sce.demo.server;

public class Server {

public static void main(String[] args) throws Exception {

Ice.Communicator ic = null;

try {

ic = Ice.Util.initialize(args);

Ice.ObjectAdapter adapter = ic.createObjectAdapterWithEndpoints("Demo", "default -p 2012");

adapter.add(new CounterServiceI(), ic.stringToIdentity("Counter"));

adapter.activate();

ic.waitForShutdown();

} finally {

if (ic != null) ic.destroy();

}

}

}

Step 5: write a client package sce.demo.client;

import sce.demo.CounterServicePrx;

import sce.demo.CounterServicePrxHelper;

public class Client {

public static void main(String[] args) {

Ice.Communicator ic = null;

try {

ic = Ice.Util.initialize(args);

Ice.ObjectPrx base = ic.stringToProxy("Counter:default -p 2012");

CounterServicePrx counter = CounterServicePrxHelper.checkedCast(base);

//

final int initValue = 100;

counter.set(initValue);

System.out.println((initValue+1)+" => "+counter.incr());

System.out.println((initValue+1)+" => "+counter.get());

System.out.println((initValue)+" => "+counter.decr());

} finally {

if (ic != null) ic.destroy();

}

}

}

101 => 101

101 => 101

100 => 100

Common Steps

1. write the slice files

2. convert slice to java source files (slice2java)

3. write the server (active the object)

4. write the client

Source Code

git

git clone git@github.com:adyliu/sce-demo.git

web

https://github.com/adyliu/sce-demo

Multi-language supported

Next

SCE full samples with Protocol Buffers

ICE more advanced topic