javaROOT

Created by Unknown User (mlynch), last modified by Jan Strube on Aug 20, 2012

Java to ROOT Interface (M. Lynch, M. Stanitzki, J. Strube)

Introduction

This provides a Java interface to a limited subset of ROOT. The code for this is currently stored on the SVN server (https://heplnm060.pp.rl.ac.uk/repos/javaROOT/trunk). There is also a precompiled version of a later version available, which does not require SWIG. Only the C++ sources then need to be built locally.

This has been tested on

Scientific Linux Fermi version 4.4, GCC version 3.4.6, Java version 1.6.0.13, ROOT version 5.25 and SWIG version 1.3.40.
Windows XP SP3, Microsoft C++ Compiler version 15.00.30729.01, MinGW 5.1.4, Java version 1.6.0.14, ROOT version 5.25 and SWIG version 1.3.40.

The libraries are built using a set of makefiles. (On Windows, these are executed using the MinGW port of GNU make, mingw32-make.)

javaROOT requires SWIG version 1.3.40 or higher, and on Windows, ROOT v.5.25

Features

javaROOT can:

create histograms (TH1Fs, TH1Ds, TH2Fs, TH2Ds, TProfiles) and fill them with data.

sess.newTH1F( "demoA", "demoA", 100, 0, 1 );
for( int i = 0; i < 4096; i++ )
{
	sess.fillTH1F( "demoA", (float) r.nextGaussian() );
}
sess.delete();

create TTrees and fill them with data (branches of type float, int, double, bool, TVector3, TLorentzVector, std::vector<float>, std::vector<int>, std::vector<double>, std::vector<bool>, std::vector<TVector3>, std::vector<TLorentzVector>).
```
sess.newTTree( "demoT", "TestTree", 99 );
sess.branchTTreeFloat( "demoT", "fX" );
for( int i = 0; i < 4096; i++ )
{
	sess.fillBranchFloat( "demoT", "fX", (float) r.nextGaussian() );
	sess.fillTTree( "demoT" );
}
sess.delete();
```

There are a set of example programs demonstrating the available functionality in ./Examples/. These are also built when the main libraries are built with "make all".

There are also a series of tests in ./Tests/ to check that certain basic ROOT functions work correctly on your platform. These are built and run using ./make Tests.

The Java libraries integrate well with Eclipse, with auto-complete working out of the box.

Building the Libraries (Linux)

Setup the JAVA_HOME environment variable. The java executable is supposed to be found in $JAVA_HOME/bin/java
Setup the ROOT environment: source <wherever you installed ROOT>/bin/thisroot.sh
Cd to the javaROOT directory.
Run make OSTYPE=linux-gnu all.
Tell the linker where to find the new shared objects. E.g. if running the example "C++", calling export LD_LIBRARY_PATH:$LD_LIBRARY_PATH:. is necessary for the program to run.
Running the Java programs requires the classpath to be set approriately, e.g. java -cp ../../jar/javaROOT.jar:../../jar/freehep-physics-2.1.jar:. Test.
If there are any problems with network exceptions on the LCSIM example, it is due to proxy servers: set these when Java is run by adding -Dhttp.proxyHost=<hostname> -Dhttp.proxyPort=<hostport> in the call to Java.

Building the Libraries (Windows)

Ensure the %ROOT_SYS% and %JDK_HOME% environment variables are set (go to System Properties (WinKey+Break), Advanced, Environment Variables) to the root folders of ROOT and the JDK respectively.
Run a Visual Studio Command Prompt.
Cd to the javaROOT root folder.
Run mingw32-make all.
Running the Java programs requires the classpath to be set approriately, e.g. java -cp ../../jar/javaROOT.jar:../../jar/freehep-physics-2.1.jar:. Test.
If there are any problems with network exceptions on the LCSIM example, it is due to proxy servers: set these when Java is run by adding-Dhttp.proxyHost=<hostname> -Dhttp.proxyPort=<hostport> in the call to Java.

Further Details

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