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Jep embeds CPython in Java through JNI.
There is a newer version: 4.2.1
/**
 * Copyright (c) 2017 JEP AUTHORS.
 *
 * This file is licensed under the the zlib/libpng License.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any
 * damages arising from the use of this software.
 * 
 * Permission is granted to anyone to use this software for any
 * purpose, including commercial applications, and to alter it and
 * redistribute it freely, subject to the following restrictions:
 * 
 *     1. The origin of this software must not be misrepresented; you
 *     must not claim that you wrote the original software. If you use
 *     this software in a product, an acknowledgment in the product
 *     documentation would be appreciated but is not required.
 * 
 *     2. Altered source versions must be plainly marked as such, and
 *     must not be misrepresented as being the original software.
 * 
 *     3. This notice may not be removed or altered from any source
 *     distribution.
 */
package jep;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptException;

/**
 * Implements {@link javax.script.ScriptEngineFactory}
 * 
 * @author Mike Johnson
 */
public class JepScriptEngineFactory implements ScriptEngineFactory {

    private static List names;

    private static List extensions;

    private static List mimeTypes;

    static {
        names = new ArrayList<>(1);
        names.add("jep");
        names = Collections.unmodifiableList(names);

        extensions = new ArrayList<>(1);
        extensions.add("py");
        // TODO add support for running compiled scripts.
        // l.add("pyo");
        // l.add("pyc");
        extensions = Collections.unmodifiableList(extensions);

        mimeTypes = new ArrayList<>(0);
        mimeTypes = Collections.unmodifiableList(mimeTypes);
    }

    /**
     * Describe getEngineName method here.
     * 
     * @return a String value
     */
    @Override
    public String getEngineName() {
        return "jep";
    }

    /**
     * Describe getEngineVersion method here.
     * 
     * @return a String value
     */
    @Override
    public String getEngineVersion() {
        return "2.x";
    }

    /**
     * (non-Javadoc)
     * 
     * @see javax.script.ScriptEngineFactory#getExtensions()
     */
    @Override
    public List getExtensions() {
        return extensions;
    }

    /**
     * Describe getLanguageName method here.
     * 
     * @return a String value
     */
    @Override
    public String getLanguageName() {
        return "CPython";
    }

    /**
     * Describe getLanguageVersion method here.
     * 
     * @return a String value
     */
    @Override
    public String getLanguageVersion() {
        return "Whatever you compiled with";
    }

    /**
     * Describe getMethodCallSyntax method here.
     * 
     * @param obj
     *            a String value
     * @param m
     *            a String value
     * @param args
     *            a String[] value
     * @return a String value
     */
    @Override
    public String getMethodCallSyntax(String obj, String m, String[] args) {
        // copied from javadoc. might be right. *shrugs*

        String ret = obj;
        ret += "." + m + "(";
        for (int i = 0; i < args.length; i++) {
            ret += args[i];
            if (i == args.length - 1)
                ret += ")";
            else
                ret += ",";
        }

        return ret;
    }

    /**
     * (non-Javadoc)
     * 
     * @see javax.script.ScriptEngineFactory#getMimeTypes()
     */
    @Override
    public List getMimeTypes() {
        return mimeTypes;
    }

    /**
     * (non-Javadoc)
     * 
     * @see javax.script.ScriptEngineFactory#getNames()
     */
    @Override
    public List getNames() {
        return names;
    }

    /**
     * Describe getOutputStatement method here.
     * 
     * @param o
     *            a String value
     * @return a String value
     */
    @Override
    public String getOutputStatement(String o) {
        return "print " + o;
    }

    /**
     * Describe getParameter method here.
     * 
     * @param p
     *            a String value
     * @return an Object value
     */
    @Override
    public Object getParameter(String p) {
        if (p == null)
            return null;

        // this is fucking retarded
        if (p.equals(ScriptEngine.ENGINE))
            return getEngineName();

        if (p.equals(ScriptEngine.ENGINE_VERSION))
            return getEngineVersion();

        if (p.equals(ScriptEngine.NAME))
            return "jep";

        if (p.equals(ScriptEngine.LANGUAGE))
            return getLanguageName();

        if (p.equals(ScriptEngine.LANGUAGE_VERSION))
            return getLanguageVersion();

        return null;
    }

    /**
     * Describe getProgram method here.
     * 
     * @param lines
     *            a String[] value
     * @return a String value
     */
    @Override
    public String getProgram(String[] lines) {
        StringBuffer ret = new StringBuffer();

        for (int i = 0; i < lines.length; i++) {
            ret.append(lines[i]);
            ret.append("\n");
        }

        return ret.toString();
    }

    /**
     * Describe getScriptEngine method here.
     * 
     * @return a ScriptEngine value
     */
    @Override
    public ScriptEngine getScriptEngine() {
        try {
            JepScriptEngine e = new JepScriptEngine();
            e.setFactory(this);
            return e;
        } catch (ScriptException e) {
            // aint this grand.
            // we can throw it in the constructor, but not here.
            throw new RuntimeException(e);
        }
    }

}