Java Analysis Studio

Tony Johnson

tony_johnson@slac.stanford.edu

Stanford Linear Accelerator Center

CHEP 97 - April 1997

Contents

• Java Analysis Studio - Goals

• Intro to Java
  • Why Java for Distributed Physics Analysis?

• Implementation
  • Why Java - Reprise

• Demo

• Current Status + Plans + Call for Input

Java Analysis Studio - Goals

• Project based
  • Data, histograms, fits, programs all stored in project.
  • Can close project and return to exact same place tomorrow

• Experiment/Data format independent

• Distributed data analysis

• Integrated with other applications

• Analysis code written in Java
  • Java excellent language for RAD == physics analysis
  • Build on SLD experience with IDA
  • Provide a rich set of OO analysis tools
    • Histograms, plots, fits etc.
  • Portable
    • compiled on desktop
    • executed on dataserver
    • Supports Remote debugging
  • Efficient (JIT)
  • Widespread industry support

PPT Slide

What is Java?

• History
  • Originally designed (1991) as a small language for consumer electronics (cable boxes, toasters etc.)
  • Eventually someone wrote HotJava Browser, which could run Java Applets
  • Adopted by Netscape, Microsoft, Sun etc. as Web Programming Language.

• More than just a Web Tool
  • Java is a fully functional, platform independent, programming language
  • Powerful set of machine independent libraries, including windowing library.

Totally Buzzword Compliant

• Simple
  • well, simpler than C++

• Object Orientated
  • more so than C++

• Distributed
  • Built in support for Internet protocols, URL’s, HTTP, Remote Method Invocation, DB access etc.

• Robust
  • “Impossible” to create memory leaks, go beyond the end of an array, corrupt stack or code

• Secure
  • Bytecode “verifier”, padded cell

• Architecture Neural, Portable
  • Runs on PC, MAC, Unix, VMS

• Interpreted
  • “Compiler” converts code into machine independent “bytecodes”

• High Performance
  • With JIT compiler still 2-3 times slower than native C++, but...

• Multithreaded
  • Language has direct support for multithreading (cf. subprocesses)

• Dynamic
  • Libraries can change without recompiling programs that use them

Where’s the Meat?

• JDK 1.1 adds:
  • Object reflection
  • Object serialization
  • Remote Method Invocation
  • CORBA support
  • JDBC interface
  • Standardized native interface
  • 2d+3d API on the way

• Extensive built in library (including Math)

• Can read in unknown data and analyze it

• Can really store objects in databases (not just object data)

• Client Server applications straightforward

PPT Slide

Why Learn Java?

• Stepping stone to C++
  • Cleaner syntax
    • not backward compatible with C
    • More concerned with programmer efficiency than run-time efficiency
  • Far less gotchas
    • Especially memory management
  • Full object orientated language
  • Syntax very similar to C++

• Good language for writing medium sized portable applications, including GUI applications

• Good candidate to replace KUIP/Comis/IDA/etc as physics analysis language

• Web Applets
  • Hopefully useful ones
    • Database access
    • Data presentation

Java for Physics Analysis

Java for Physics Analysis - 2

Implementation- Model

GUI

Data

Analysis

Engine

Experiment

Interface

Experiment

Extensions

(Event Display)

TCP/IP Network

Padded Cell

C++ Code

Data

• Zebra
• Jazelle
• Paw
• Root
• Objectivity

Implementation - Details

• Original plan was to write C++/MFC/COM application for Windows

• Later converted to 100% pure Java
  • Works everywhere
  • Fast (enough)
  • Rapid deployment of commercial tools
    • IDE’s
    • Extensions
    • Components

• Use commercial “components” where ever possible
  • Don’t want to write our own plotting package
    • Olectra Chart
      • C++ activeX control
    • Jchart
      • Java “Bean”
    • Wrap in interface layer to make it possible to change later.

C++/Java Comparison

Implementation - Local Objects

Histogram

Analysis

Studio

Histogram

Analysis

Studio

Plot

Plot

Data request

Data + Update Notifications

PPT Slide

Implementation - Remote Objects

Histogram

Analysis

Studio

Histogram

Analysis

Studio

Plot

Plot

Remote Adaptors

Deal with data batching,

Caching, network

exceptions

Lessons Learned - 1

• Microsoft programmers drink too much Jolt Cola
  • Win32/MFC/COM/ActiveX system was not designed to be easy to learn
    • WHILE (< having problems learning system>)
      < more documentation>
  • Microsoft is changing/extending things faster than the speed of learning
  • Once things fall into place it is possible to exploit Microsoft environment to rapidly build applications

Lessons Learned - 2

• Commercial software components can be very cost effective
  • Commodity software has large market, therefore cheap
    • Commercial plot package with more options than HBOOK cost $249, with no run time license.
  • Can wrap commercial components with HEP component layer

Demo!!!

Current Status + Plans

• Web site
  • http://www-sldnt.slac.stanford.edu/JAS
    • Version 0.1 available for download end of April
      • client+server
      • masochists only!
    • Join discussion group
    • We want your input
      • Ideas, Opinions and/or Code!