com.qspin.qtaste.util.PythonHelper.java Source code

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Here is the source code for com.qspin.qtaste.util.PythonHelper.java

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/*
Copyright 2007-2009 QSpin - www.qspin.be
    
This file is part of QTaste framework.
    
QTaste is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
QTaste is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.
    
You should have received a copy of the GNU Lesser General Public License
along with QTaste. If not, see <http://www.gnu.org/licenses/>.
*/

package com.qspin.qtaste.util;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Properties;

import org.apache.commons.lang.StringUtils;
import org.python.core.PyException;
import org.python.util.PythonInterpreter;

import com.qspin.qtaste.config.StaticConfiguration;

/**
 * Python helper class.
 *
 * @author David Ergo
 */
public class PythonHelper {

    /**
     * Executes a python script and return its output.
     *
     * @param fileName the filename of the python script to execute
     * @param arguments the arguments to pass to the python script
     * @return the output of the python script execution (combined standard and error outputs)
     * @throws PyException in case of exception during Python script execution
     */
    public static String execute(String fileName, String... arguments) throws PyException {
        return execute(fileName, true, arguments);
    }

    /**
     * Executes a python script, returning its output or not.
     *
     * @param fileName the filename of the python script to execute
     * @param redirectOutput true to redirect outputs and return them, false otherwise
     * @param arguments the arguments to pass to the python script
     * @return the output of the python script execution (combined standard and error outputs) or null if outputs were not
     * redirected
     * @throws PyException in case of exception during Python script execution
     */
    public static String execute(String fileName, boolean redirectOutput, String... arguments) throws PyException {
        Properties properties = new Properties();
        properties.setProperty("python.home", StaticConfiguration.JYTHON_HOME);
        properties.setProperty("python.path", StaticConfiguration.FORMATTER_DIR);
        PythonInterpreter.initialize(System.getProperties(), properties, new String[] { "" });

        try (PythonInterpreter interp = new PythonInterpreter(new org.python.core.PyStringMap(),
                new org.python.core.PySystemState())) {
            StringWriter output = null;
            if (redirectOutput) {
                output = new StringWriter();
                interp.setOut(output);
                interp.setErr(output);
            }
            interp.cleanup();
            interp.exec("import sys;sys.argv[1:]= [r'" + StringUtils.join(arguments, "','") + "']");
            interp.exec("__name__ = '__main__'");
            interp.exec("execfile(r'" + fileName + "')");
            return redirectOutput ? output.toString() : null;
        }
    }

    /**
     * Gets message of a PyException.
     * If internal message is null, uses printStackTrace() method to build message.
     *
     * @param e PyException
     * @return message string
     */
    public static String getMessage(PyException e) {
        if (e.getMessage() != null) {
            return e.getMessage();
        } else {
            StringWriter stringWriter = new StringWriter();
            e.printStackTrace(new PrintWriter(stringWriter));
            return stringWriter.toString();
        }
    }
}