/**
 * =========================================================
 * Pentaho-Reporting-Classic : a free Java reporting library
 * =========================================================
 *
 * Project Info:  http://reporting.pentaho.org/
 *
 * (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ------------
 * BeanShellModule.java
 * ------------
 * (C) Copyright 2001-2007, by Object Refinery Ltd, Pentaho Corporation and Contributors.
 */

package org.jfree.report.modules.misc.beanshell;

import java.io.InputStream;
import java.net.URL;

import org.jfree.report.metadata.ExpressionRegistry;
import org.pentaho.reporting.libraries.base.boot.AbstractModule;
import org.pentaho.reporting.libraries.base.boot.ModuleInitializeException;
import org.pentaho.reporting.libraries.base.boot.SubSystem;
import org.pentaho.reporting.libraries.base.util.ObjectUtilities;


/**
 * The module definition for the beanshell expression support module.
 *
 * @author Thomas Morgner
 */
public class BeanShellModule extends AbstractModule
{
  /**
   * DefaultConstructor. Loads the module specification.
   *
   * @throws ModuleInitializeException if an error occured.
   */
  public BeanShellModule ()
          throws ModuleInitializeException
  {
    loadModuleInfo();
  }

  /**
   * Initializes the module. Use this method to perform all initial setup operations. This
   * method is called only once in a modules lifetime. If the initializing cannot be
   * completed, throw a ModuleInitializeException to indicate the error,. The module will
   * not be available to the system.
   *
   * @param subSystem the subSystem.
   * @throws ModuleInitializeException if an error ocurred while initializing the module.
   */
  public void initialize (final SubSystem subSystem)
          throws ModuleInitializeException
  {
    final InputStream in =
            ObjectUtilities.getClassLoader(getClass()).getResourceAsStream(BSHExpression.BSHHEADERFILE);
    if (in == null)
    {
      throw new ModuleInitializeException("Unable to locate BSHHeaderFile. " + //$NON-NLS-1$
              "This file is required to execute the BeanShellExpressions."); //$NON-NLS-1$
    }
    try
    {
      ObjectUtilities.getClassLoader(getClass()).loadClass("bsh.Interpreter"); //$NON-NLS-1$
    }
    catch (Exception e)
    {
      throw new ModuleInitializeException("Unable to load the bean shell interpreter class. " + //$NON-NLS-1$
              "This class is required to execute the BeanShellExpressions."); //$NON-NLS-1$
    }

    final URL expressionMetaSource = ObjectUtilities.getResource
        ("org/jfree/report/modules/misc/beanshell/meta-expressions.xml", BeanShellModule.class);
    if (expressionMetaSource == null)
    {
      throw new ModuleInitializeException("Error: Could not find the expression meta-data description file");
    }
    try
    {
      ExpressionRegistry.getInstance().registerFromXml(expressionMetaSource);
    }
    catch (Exception e)
    {
      throw new ModuleInitializeException("Error: Could not parse the element meta-data description file", e);
    }

  }
}