Практики применения JRuby

JRuby
Практика применения

Short history

• 2001 - the ﬁrst version of JRuby(by Jan
Arne Petersen)

Short history

Arne Petersen)
• 2006 - version 0.9.0(by Charles Nutter,
Thomas Enebo, Ola Bini and Nick Siege)

Short history

Arne Petersen)
• 2006 - version 0.9.0(by Charles Nutter,
Thomas Enebo, Ola Bini and Nick Siege)
• 2007 - version 1.0(passed all Rails tests)

Why JRuby?
• Multithreading
• JVM

Why JRuby?
• Multithreading
• JVM
• Cross-platform

Why JRuby?
• Multithreading
• JVM
• Cross-platform
• Just another .jar

Why JRuby?
• Multithreading
• JVM
• Cross-platform
• GUI

Why JRuby?
• Multithreading
• JVM
• Cross-platform
• GUI
• Android

JVM

• Concurrent threading
• Garbage collectors

JVM

• JIT compiler

JVM

• JIT compiler
• invokedynamic(JDK 7)

Missing features
• Memory footprint

Missing features
• No Kernel#fork

Missing features
• No Kernel#fork
• No continuations(callcc)

Missing features
• No Kernel#fork
• ObjectSpace off by default(-X+O to enable)

Missing features
• No Kernel#fork
• ObjectSpace off by default(-X+O to enable)
• set_trace_func off by default(--debug to
enable)

C extensions

since JRuby 1.6(still experimental)

Easy installing

• rvm install jruby
• rbenv install jruby-1.6.6 (*)
• Download from http://jruby.org

Compatibilities

Ruby 1.8.7 & 1.9.2 compatible
(default 1.8)
ﬂag `jruby --1.9` for 1.9.2 compatibility

Nailgun
(since 1.3.0 version)

Nailgun is a client, protocol, and server for
running Java programs in the server.

Nailgun
(since 1.3.0 version)

Nailgun is a client, protocol, and server for
running Java programs in the server.

$ jruby --ng-server &
$ jruby --ng -e "puts 1"

Multi-VM support
many apps in one process

Multi-VM support

JVM

Multi-VM support

JRuby JRuby JRuby JRuby JRuby

JVM

Benchmarks
jruby 1.7.0.dev(JDK 6) jruby 1.7.0.dev(JDK 7) invokedynamic=false
jruby 1.7.0.dev(JDK 7) ruby 1.9.3-p0

Benchmarks
jruby 1.7.0.dev(JDK 6) jruby 1.7.0.dev(JDK 7) invokedynamic=false
jruby 1.7.0.dev(JDK 7) ruby 1.9.3-p0

4

3

2

1

0
bench/bench_red_black.rb (sec)

JVM + JRuby

• Swing, SWT
• JavaFX

JVM + JRuby

• Swing, SWT
• JavaFX
• Spring & Hibernate

JVM + JRuby

• Swing, SWT
• JavaFX
• Spring & Hibernate
• Scala, Groovy, Jython, Clojure, ...

Java + Ruby
• require ‘java’

Java + Ruby
• Java namespace

Java + Ruby
• Java namespace
• Snake case(get_some vs getSome)

Java + Ruby
• Java namespace
• Ruby-style accessors(length= vs setLength)

Java + Ruby
• Java namespace
• Converting types

Java + Ruby
• Java namespace
• Converting types
• Swing IRB(command: jirb_swing)

Java bridge
Collections

Java List:
java_list[0]
java_list << 5
java_list += 7

Java bridge
Collections

Java List: Java Map:
java_list[0] java_list[‘key’]
java_list << 5 java_list[‘key’] = 5
java_list += 7

Java bridge
Collections

Java List: Java Map:
java_list[0] java_list[‘key’]
java_list << 5 java_list[‘key’] = 5
java_list += 7

Ruby List:
[1, 2, 3].to_java :int
[“string”].to_java :string

Java bridge
Overloading

Java:
public class Test {
public boolean isSome(String arg) {...}
public boolean isSome(int arg) {...}
public boolean isSome(long arg) {...}
public boolean isSome(Object arg) {...}
}

Java bridge
Overloading

Ruby:
Test.new.java_send :isSome, [Java::long], 1_000
or
class Test
java_alias :is_some, :isSome, [Java::long]
...
end

Java bridge
Annotations

Java:
@Bean(scope = Scope.PROTOTYPE)
public class Person {
...
}

Java bridge
Annotations

Ruby:
java_import Bean
java_import Scope

class Person
end

Person.add_class_annotation(Bean: {
‘scope’ => Scope.PROTOTYPE
})
Person.become_java!

Java bridge
Interfaces

Ruby:
class Posts
include java.util.Iterator
end

JRuby compiler
Ahead-Of-Time Compilation

$ jrubyc <script name>.rb
$ java -cp .:/path/to/jruby.jar <script name>

JRuby compiler
Generate .java classes from .rb

$ jrubyc --java <script name>.rb

JRuby compiler

Ruby:
require 'java'

class Vec
def initialize(x, y)
@xcoord = x
@ycoord = y
end
end

JRuby compiler
Ruby:
require 'java'

class Vec
java_signature 'Vec(double x, double y)'
def initialize(x, y)
@xcoord = x
@ycoord = y
end
end

JRuby compiler
Java:
import org.jruby.Ruby;
import org.jruby.RubyObject;
import org.jruby.RubyClass;
...
public class Vec extends RubyObject {
...
public Vec(double x, double y) {
...
}
}

Rake + Ant

Ant tasks like Rake tasks:
task :ant_import do
ant_import
end

Buildr
http://buildr.apache.org

Apache Buildr is a build system for Java-based
applications, including support for Scala, Groovy and a
growing number of JVM languages and tools.

Buildr

Buildr

• Projects and sub-projects

Buildr

• Compiling, copying and ﬁltering resources,
test cases, Javadoc and more

Buildr

• Builds what has changed since the last release

Buildr

• Support Maven 2.0

Buildr

• Support Ant

Buildr

• Support Ant
• Buildr is Ruby all the way down

Buildr
buildﬁle:
repositories.remote "http://repo.typesafe.com/typesafe/releases/"

desc "The Springmongodb project"
deﬁne "SpringMongoDB" do
project.version = "0.1"
project.group = "SpringMongoDB"

run.with "org.jruby:jruby-complete:jar:1.6.6",
"org.mongodb:mongo-java-driver:jar:2.7.2",
"org.springframework:spring-core:jar:3.1.0.RELEASE",
"org.springframework:spring-context:jar:3.1.0.RELEASE",
"org.springframework:spring-beans:jar:3.1.0.RELEASE",
'org.springframework.data:spring-data-commons-core:jar:1.1.0.RELEASE',
"org.springframework.data:spring-data-mongodb:jar:1.0.0.RC1"

run.using main: ['org.jruby.Main', _(:src, :main, :ruby, "app.rb")]
end

Rawr
http://rawr.rubyforge.org

Rawr, a packaging and deployment tool, that allows turns your
code into an executable jar, a .exe for Windows, and a .app for
OS X.

Rawr
http://rawr.rubyforge.org

$ gem install rawr
$ rawr install
...
$ rake rawr:jar

JRuby-Rack

Servlet JRuby-Rack Rack
Rack
container servlet ﬁlter application

JRuby servers

WEBrick

Trinidad

JRuby servers

WEBrick

Trinidad

TorqueBox

TorqueBox
http://torquebox.org

TorqueBox

Installation:
jruby -S gem install torquebox-server --pre

TorqueBox

Usage:
torquebox deploy ~/Projects/rails_app
torquebox run

Warbler

Warbler is a gem to make a Java jar or war ﬁle
out of any Ruby, Rails, Merb, or Rack application.

Warbler

Installation:
jruby -S gem install warbler

Warbler
Standalone application:

Tuning ﬂags

• --server - server compiler

Tuning ﬂags

• -Xmx - max heap size

Tuning ﬂags

• -Xmx - max heap size
• -XX:+UnlockExperimentalVMOptions
-XX:+UseG1GC - new GC(JDK 7)

Clouds
• Amazon Elastic Beans(http://aws.amazon.com/
elasticbeanstalk/)

• Jelastic(http://jelastic.com)
• Engine Yard(http://www.engineyard.com)
• Google App Engine(http://
appengine.google.com)

Bot Hunter

• Multithreading

Bot Hunter

• Multithreading
• Some logic on Scala

Yukihiro Matsumoto: “I would remove the
thread and add actors or some other more
advanced concurrency features”.

Akka
http://akka.io/

Simpler Concurrency, Scalability & Fault-
tolerance through Actors

slidesha.re/akka-scala-days-2010

Actor Model of
Concurrency


Actor Model of
Concurrency
• Implements Message-Passing Concurrency


Actor Model of
Concurrency
• Share nothing


Actor Model of
Concurrency
• Share nothing
• Isolated lightweight process


Actor Model of
Concurrency
• Share nothing
• Communicates through messages


Actor Model of
Concurrency
• Share nothing
• Asynchronous and non-blocking

Actor Model of
Concurrency
• Share nothing
• Asynchronous and non-blocking
• Each actor has a mailbox(message queue)

Two different models



• Thread-based



• Thread-based
• Event-based



• Thread-based
• Event-based
• Very lightweight(~300 bytes per actor)



• Thread-based
• Event-based
• Very lightweight(~300 bytes per actor)
• Can easily create millions on a single
workstation


Example


Server code
class HelloWorldActor extends UntypedActor {
public void onReceive(Object msg) {
getContext().tryReply(msg + " World");
}
}
remote().start("localhost", 2552).register(
"hello-service",
actorOf(HelloWorldActor.class));


Client code

actor = Actors.remote.actorFor(
"hello-service", "localhost", 2552)
res = actor.ask("Hello").get


java.lang.NullPointerException

Questions?

Email: klimtimothy@gmail.com

Практики применения JRuby

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