Jalimo Slides Linuxtag2007 (English)

Java-Linux-Mobile Platform

Status
Increasing number of small mobile Linux devices
Java on mobile mobile and embedded devices
Classpath & friends are 'grown up'
but!
Free java on Linux-embedded is rarely in use

Java embedded?
What is Java?
J2ME CLDC
J2ME CDC
J2ME CDC + AGUI (JSR 209)
J2SE
Only certified platforms (JVMs+class libraries) are allowed to be named 'Java'.
The alternative, free JVMs are not certified

Java and Java-like Implementations
Sun J2SE – (GPL and proprietary)
Sun J2ME PhoneME (GPL)
J2ME IBM J9 (proprietary)
Gnu Classpath (GPL) with different JVMs
cacaojvm (GPL)
jamvm (GPL)
kaffe (GPL)
...
Aonix, Perc (proprietary)
Aicas, JamaicaVM (proprietary)
...
}
Realtime capable

As always - the GUI makes it!
Except J2ME CLDC everything is ~ Java 1.3.
Concise: The different GUI attempts.
MIDP 2.0 (minimal)
AWT (small amount of features)
Swing (problems in performance)
SWT (with GTK peer: many dependencies)
SWT (with QT peer: proprietary)
further possibilities
Java-gnome
escher (pure java X library)
jsdl (java sdl bindings)

Pocket-Size Linux
Distributions
Familiar (OpenEmbedded, ipkg)
Ångström (OpenEmbedded, ipkg)
Maemo (Scratchbox, apt, dpkg)
OpenMoko (OpenEmbedded, ipkg)
Environments
Opie (Framebuffer/QT embedded)
GPE (Xserver/GTK)
Maemo (Xserver/GTK + Hildon + Osso)
OpenMoko (Xserver/GTK + libmokoui + libmokocore)

Java @ Pocket-Size Linux
mostly sporadic:
e.g. jamvm and the old gnu classpath
seldomly updated
no concept for packaging and further integration
GUI: mostly AWT (with gtk peer)
OpenEmbedded: jamvm 1.4.2/classpath 0.90
Maemo:
jamvm 1.4.2/classpath 0.91 (without 'hildonizing')
sun PhoneME (as tar.gz, without gui)
JaLiMo

Which problems exist?
at the Java-Porting
the Build Process is different, mostly
dependencies for the GUI
missing optimisation for the embedded area
size & modularization
startup-speed
in development
Embedded Java is different
missing integration in the environments
packaging + dependency management
missing dependencies and bindings
bad framework/toolchain support

JaLiMo
JaLiMo is an initiative to build a complete free Java-Stack for mobile Linux devices.
the integration and completion of existing projects has the focus.
"Java-like environment for mobile Linux devices" Main tasks are the problems after porting the JVM!

JaLiMo - Who?
sponsored by the Tarent GmbH
Sebastian Mancke
Robert Schuster (Gnu Classpath)
Fabian Köster
Unterstützt durch
Christian Thalinger (cacaojvm.org)
Roman Kennke (Gnu Classpath, escher)
Guillaume Legris (MIDPath)
Andrew Cowie (java-gnome)
...

JaLiMo - What? Integration Integration GUI Runtime Build Plattform CACAO JVM JamVM GNU Classpath phoneME MIDPath Swing/escher java-gnome SWT maven packaging plugin OpenEmbedded integration mvn2deb libjalimo-core libopenmoko libmaemo maemo ...?... openmoko

Build Strategies - Cross Compiling
Cross Toolchain (gcc, ld, .. for arm)
Rootstrap
setting: PATH, CC, LD, AR, PKG_CONFIG_PATH
wrapper for: dpkg-architecture and pkg-config
Advantages:
the host tools (z.B. javac, javah, jar) are available.
useage in combination with dpkg-buildpackage
Problems:
keeping Rootstrap up to date
prone to errors by missing chroot

Build Strategies - Scratchbox
an emulator based on Qemu
integrated with Toolchain and Rootstrap
Advantages:
direct copy of the target system
no more Cross Compiling
Problems:
no support of special Build Tools (z.B. javac, javah, ..)
Java binaries (e.g. jamvm or cacao) are not working in scratchbox

Build Strategies - maven2
established Java Build environment
Advantages:
Management of dependencies
Standardized Build Process
Plugin Architekture
Disadvantages:
highly Java centred
bad support for JNI and Cross Compiling
no packaging conzept

maven packaging plugin
Packaging
IzPack installer (for desktop)
.deb (for desktop and embedded)
.ipkg (planned)
generation of startscripts
orientation towards debian guidelines
conversion of the maven dependencies to debian dependencies
A maven plugin, developed by the tarent (Robert Schuster) to pack projects – released under (GPL).

maven packaging plugin
Java package for maemo in 5 minutes!
.. writing of code and adaptation of pom.xml ..
.. and the .deb archive is complete!
mvn archetype:create -DarchetypeGroupId=org.jalimo.archetype -DarchetypeArtifactId=gtkapp -DarchetypeVersion=0.1.0-SNAPSHOT -DremoteRepositories=http://www.jalimo.org/maven -DgroupId=<your project group id> -DartifactId=<your artifact id> mvn -Dmaven.test.skip=true pkg:deb

maven with JNI code
normal maven packaging project + makefile
Process: mvn pkg:deb
compiling of the Java classes
generation of the header files with javah
compiling of the C-code in scratchbox through /scratchbox/login <scriptfile>
collection of the binaries
generation of the .deb archives
Many projects are composed of java and C code
} } }
Host
Host
Emulator
example: java-gnome

Java-gnome
Java-gnome a project, that already exists for 9 years
the 2 nd version has a quite high API-cover, but too many problems
since the last 1,5 years: rewrite java-gnome4
clean Design
lightweight
small API-cover
unfortunately just makes slow progress
But: a good concept

Java-gnome - concept
Code Generation of the JNI layer
Object definitions are built from the GTK header files.
For each Gtk 'class' a C and Java file is generated that contains the whole JNI-code.
Java scopes of this layer are restricted to 'package'.
In a clean API layer the realization of the procedural code happens in a object-oriented API.
The GTK's pseudo-class structure is properly mapped in Java.
This way and the code generator are possibly suitable for other libraries: e. g. hildon or libopenmoko.

Java-gnome
Why Java-gnome
high-performance, small
Possibility of smooth integration
support by Glade2 GUI Builder
simple, lovely API

Java-gnome - coverage
very low in the upstream:
Window, Widget, Button, Label, Hbox, VBox
prototypical enhancements on two evenings:
Entry
TextView, TextBuffer
ToggleButton
CheckButton
ComboBox
MenuBar, Menu, MenuItem
ScrolledWindow
Frame
Notebook
HSeparator, VSeparator
Image
Obviously: good concept!

libmaemo
Enhancements of the java-gnome components with bindings to the Hildon framework. Necessary steps:
Wrapper for HildonWindow and HildonProgram (already existing)
Enhanced Widgets of the Hildon Frameworks
Bindings for Status Bar Plugins
Wrapper for the libosso
communication between applications
maybe possible with the existing project java-dbus

MIDPath
MIDPath is a MIDP2 implementation based on MIDP
code of Sun's PhoneME.
On the opposite to PhoneME, MIDPath runs on Java SE as well as Java ME CLDC.
By that it can be used out of the box with Kaffe, Cacao, JamVM or other JVMs.
Guillaume Legris has written a GTK Backend for JaLiMo, that we were able to fit to the Maemo Input Framework.

MIDPath - architekture
By different Backends, the MIDPath is quite portable.
For the use on small devices, there is an alternative using the Cacao CLDC Version.
MIDPATH Java ME CLDC AWT SWT JavaSound SDL X11 ALSA Cacao JamVM Kaffe Cacao CLDC GNU Classpath JVMs Standard Libraries Backends Core GTK

MIDPath - Status
Status:
quite stable
APIs: JSR-118 + FileConnection (JSR-75)
Missing: SSL, UDP, tone playing
OGG/MP3 support
Soon:
Audio streaming support
Midlet managment for Maemo
Future:
adding further Java ME JSRs

Swing/Escher
Swing/AWT Support of GNU Classpath in maemo would require a higher gtk version.
Alternative
Pure Java X library: Escher
Classpath has different peers for AWT and Swing
Swing/Escher runs on maemo, but is still in progress:
problems with the handlig of windows
repainting
soft keyboard input
look and feel customizing

Swing/Escher – Difficulty of Maemo Input
Soft Keyboard doesn't activate any X Key-Events
text oriented
undocumented Xmessages, that are realized over the Hildon/GTK Input Framework in GTK.
TODO:
Generation of XMessages on Softkeyboard (raise/lower)
Receiving of Messages, conversion in AWT Key Events

lib-JaLiMo
the JaLiMo project ist still getting off the ground
completeness of a 1.0 is planned for the end of 2008
so far: focus on the basis platform
the main focus is on applikation framework
Creation of mobile applications for the realization of end-to-end business processes.

lib-JaLiMo concepts
Messaging
Asynchrone messaging as the application's basis
connection of different sources with connectors, e.g. SOAP/HTTP, XMPP, RMI, dbus
application MessageBroker

lib-JaLiMo concepts
Data-Binding
Bindung of data and view through messages to each other
declarative connection, without two-way referencing of the specific objects
offers stronger decoupling than MVC-paradigm
Action Framework
consequent use of the Command Pattern in GUI applications
All actions are definded as Action and can be used in different cases.

lib-JaLiMo Konzepte
GUI Templating
Creation of parts of the GUI by using description languages, e.g.
HTML embedded in Swing
Glade für Java-Gnome
JSP oder Velocity für Web
Combination of GUI and application with actions and bindings
Aim:
easier re-use of applications in different contexts
rapid prototyping
division of designing and development

JaLiMo - Robots
Why? To clarify how easy open standard components are for comlpex architectures.
autonomous Java controller
Java-gnome GUI
Asynchronous communication over XMPP
effort of the development
~ 1 week

Jazelle DBX (Direct Bytecode eXecution)
The N770 and the N800 have the proprietary Jazelle enhancement in their processor.
DBX is an additional instruction modus of the arm processor.
after a so called branch to java, the bytecode can be executed local.
123 bytecodes are supported, directly. A software interrupt is activated for the rest.
Unfortunately Arm holds back the specification!!!
Is it possible to use it, anyway?

Jazelle DBX (Direct Bytecode eXecution)
To change to the DBX-Modus seems to be no problem
Debugging with gdb shows, that the program always crashes after the last correct bytecode. All the earlier ones seem to be proceeded.
After one of the untreated bytecodes, the program counter is 0x11000. This seems to be the state after an interrupt.
Open questions:
Who has an interupt handler to look like?
How may parameters beeing passed and returned?

JaLiMo Resources
www.jalimo.org
Soon in addition: www.elvolvis.org
Gforge infrastructure
open svn
Mailinglists
better management of individual projects
in other respects: [email_address]

http://www.jalimo.org	49
http://wendong.ngphone.com	32
http://ngphone.com	32
http://jalimo.org	14
http://www.netvibes.com	2

Jalimo Slides Linuxtag2007 (English)

by smancke on Jun 04, 2007

Accessibility

Categories

Tags

Upload Details

Usage Rights

5 Embeds 129

Statistics

Jalimo Slides Linuxtag2007 (English) — Presentation Transcript