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
javaexecutable 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.