/*
 * Copyright (c) 1998-2005 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *   Free SoftwareFoundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Sam
 */

package com.caucho.widget.impl;

import com.caucho.util.L10N;
import com.caucho.widget.WidgetException;

import javax.script.*;

public class WidgetScript
{
  private static final L10N L = new L10N(WidgetScript.class);

  private ScriptEngineManager _scriptEngineManager;

  private String _text;
  private String _language = "js";

  private ScriptEngine _scriptEngine;
  private CompiledScript _compiledScript;

  public WidgetScript()
  {
    _scriptEngineManager = new ScriptEngineManager();
  }

  void setLanguage(String language)
  {
    if (_language == null)
      throw new IllegalArgumentException(L.l("`{0}' cannot be null", "language"));

    _language = language;
  }

  public void setText(String text)
  {
    _text = text;
  }

  public void init()
    throws WidgetException
  {
    if (_text == null || _text.length() == 0)
      throw new WidgetException(L.l("script has no contents"));
  }

  public void compile()
    throws WidgetException
  {
    ScriptEngine engine = _scriptEngineManager.getEngineByName(_language);

    if (engine == null)
      throw new IllegalArgumentException(L.l("No script engine found for language `{0}'", _language));

    _scriptEngine = engine;
    
    if (engine instanceof Compilable) {
      Compilable compilable = (Compilable) _scriptEngine;

      try {
        _compiledScript = compilable.compile(_text);
      }
      catch (ScriptException e) {
        throw new WidgetException(e);
      }
    }
  }

  public void exec(WidgetScriptContext scriptContext)
    throws WidgetException
  {
    try {
      if (_compiledScript != null)
        _compiledScript.eval(scriptContext);
      else
        _scriptEngine.eval(_text, scriptContext);
    }
    catch (Exception e) {
      throw new WidgetException(e);
    }
  }
}
