ScriptCommandlet.java

package me.desht.scrollingmenusign.commandlets;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;

import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.SimpleBindings;

import me.desht.dhutils.Debugger;
import me.desht.dhutils.LogUtils;
import me.desht.scrollingmenusign.DirectoryStructure;
import me.desht.scrollingmenusign.SMSException;
import me.desht.scrollingmenusign.SMSValidate;
import me.desht.scrollingmenusign.ScrollingMenuSign;
import me.desht.scrollingmenusign.views.CommandTrigger;
import me.desht.scrollingmenusign.views.SMSView;

import org.bukkit.command.CommandSender;

public class ScriptCommandlet extends BaseCommandlet {

    public ScriptCommandlet() {
        super("SCRIPT");
    }

    @Override
    public boolean execute(ScrollingMenuSign plugin, CommandSender sender, CommandTrigger trigger, String cmd, String[] args) {
        SMSValidate.isTrue(args.length >= 2, "Usage: " + cmd + " <script-name> [<script-args>]");

        ScriptEngineManager manager = new ScriptEngineManager();
        String scriptName = args[1];
        int idx = scriptName.lastIndexOf('.');
        String ext = scriptName.substring(idx + 1);
        ScriptEngine engine = manager.getEngineByExtension(ext);
        SMSValidate.notNull(engine, "no scripting engine for " + scriptName);
        Debugger.getInstance().debug("running script " + scriptName + " with " + engine.getFactory().getEngineName());

        Bindings bindings = new SimpleBindings();
        if (args.length > 2) {
            String[] scriptArgs = new String[args.length - 2];
            System.arraycopy(args, 2, scriptArgs, 0, scriptArgs.length);
            bindings.put("args", scriptArgs);
        } else {
            bindings.put("args", new String[0]);
        }
        bindings.put("view", trigger instanceof SMSView ? trigger : null);
        bindings.put("trigger", trigger);
        bindings.put("commandSender", sender);
        bindings.put("result", true);
        File scriptFile = new File(DirectoryStructure.getScriptsFolder(), scriptName);
        boolean retval = true;
        try {
            engine.eval(new BufferedReader(new FileReader(scriptFile)), bindings);
            Object o = bindings.get("result");
            if (o instanceof Boolean) {
                retval = (Boolean) o;
                Debugger.getInstance().debug("script " + scriptName + " returns: " + retval);
            }
        } catch (FileNotFoundException e) {
            throw new SMSException("no such script " + scriptName);
        } catch (ScriptException e) {
            LogUtils.warning("Script " + scriptName + " encountered an error:");
            LogUtils.warning("  " + e.getMessage());
            throw new SMSException("script encountered an error (see server log)");
        }
        return retval;
    }
}