ScriptModuleLoader.java

package org.freecode.irc.votebot;

import org.freecode.irc.votebot.api.ExternalModule;
import org.freecode.irc.votebot.modules.admin.LoadModules;
import org.python.core.PyObject;
import org.python.util.PythonInterpreter;

import javax.script.ScriptException;
import java.io.File;
import java.io.IOException;
import java.util.Properties;

/**
 * Loads scripted modules for FreeVoteBot.
 * Modules may be scripted in Jython
 *
 * @author Shivam Mistry
 */

public class ScriptModuleLoader {


    private final FreeVoteBot fvb;


    /**
     * Initialises a ScriptModuleLoader
     *
     * @param fvb the instance of {@link FreeVoteBot} where the modules should be loaded to
     */
    public ScriptModuleLoader(FreeVoteBot fvb) {
        this.fvb = fvb;
        Properties props = new Properties();
        props.setProperty("python.path", new File(".", "target").getAbsolutePath()
                + ":" + LoadModules.MODULES_DIR.getAbsolutePath());
        PythonInterpreter.initialize(System.getProperties(), props,
                new String[]{""});
    }


    /**
     * Loads a module from a Python file that contains a class with the <b>SAME</b> name as the file.
     * The class must extend {@link ExternalModule}.
     *
     * @param f the file to load the {@link org.freecode.irc.votebot.api.ExternalModule} from
     * @return the {@link ExternalModule} loaded, or <tt>null</tt>
     * @throws IOException     if the file was not found
     * @throws ScriptException if the script failed to load
     */
    public ExternalModule loadFromFile(final File f) throws IOException, ScriptException {
        if (f == null || !f.exists()) {
            throw new IOException("Invalid file");
        }
        if (f.getName().endsWith(".py")) {
            PythonInterpreter interpreter = new PythonInterpreter();
            String clzName = f.getName().replace(".py", "");
            interpreter.exec(String.format("from %s import %s", clzName, clzName));
            PyObject pyClass = interpreter.get(clzName);
            PyObject buildObject = pyClass.__call__();
            ExternalModule ext = (ExternalModule) buildObject.__tojava__(ExternalModule.class);
            ext.setFvb(fvb);
            ext.setExtName(clzName);
            interpreter.cleanup();
            return ext;
        }
        return null;

    }
}