/*
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is the Kowari Metadata Store.
 *
 * The Initial Developer of the Original Code is Plugged In Software Pty
 * Ltd (http://www.pisoftware.com, mailto:info@pisoftware.com). Portions
 * created by Plugged In Software Pty Ltd are Copyright (C) 2001,2002
 * Plugged In Software Pty Ltd. All Rights Reserved.
 *
 * Contributor(s): N/A.
 *
 * [NOTE: The text of this Exhibit A may differ slightly from the text
 * of the notices in the Source Code files of the Original Code. You
 * should use the text of this Exhibit A rather than the text found in the
 * Original Code Source Code for Your Modifications.]
 *
 */

package org.mulgara.resolver.jar;

// Java 2 standard packages
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

// local packages
import org.jrdf.graph.Node;
import org.jrdf.graph.URIReference;
import org.mulgara.content.Content;
import org.mulgara.content.ContentHandler;
import org.mulgara.content.ContentHandlerManager;
import org.mulgara.content.ContentResolver;
import org.mulgara.resolver.spi.GlobalizeException;
import org.mulgara.resolver.spi.Resolver;
import org.mulgara.resolver.spi.ResolverException;
import org.mulgara.resolver.spi.ResolverSession;

// Third party packages
import org.apache.log4j.Logger;

/**
 * Resolves constraints in models defined by Jar URLs.
 *
 * @created 2004-11-09
 *
 * @author Tate Jones
 *
 * @version $Revision: 1.8 $
 *
 * @modified $Date: 2005/01/05 04:58:46 $ @maintenanceAuthor $Author: newmana $
 *
 * @company <a href="mailto:info@PIsoftware.com">Plugged In Software</a>
 *
 * @copyright © 2004 <a href="http://www.PIsoftware.com/">Plugged In
 *      Software Pty Ltd</a>
 *
 * @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
 */
public class JarResolver extends ContentResolver {
  /**
   * Logger.
   */
  @SuppressWarnings("unused")
  private static final Logger logger = Logger.getLogger(JarResolver.class.getName());

  /**
   * Construct a resolver.
   *
   * @param resolverSession  the session this resolver is associated with
   * @param contentHandlers  the available {@link ContentHandler}s
   * @throws IllegalArgumentException  if <var>resolverSession</var> is
   *   <code>null</code>
   */
  JarResolver(ResolverSession resolverSession,
              Resolver systemResolver,
              ContentHandlerManager contentHandlers) {

    super(resolverSession, systemResolver, contentHandlers);
  }

  //
  // Methods implementing ContentResolver
  //

  /**
   * Convert a local node number representing a <code>Jar:</code> model into
   * {@link JarContent}.
   *
   * @param model  the local node number of a <code>Jar:</code> URL
   * @throws ResolverException if the <var>model</var> doesn't correspond to a
   *   {@link URL} with the <code>Jar:</code> protocol.
   */
  protected Content toContent(long model) throws ResolverException {

    // Container for our model's URI
    URI modelURI;

    // Container for our globalised node
    Node globalModel = null;

    try {

      // Globalise the model
      globalModel = resolverSession.globalize(model);
    } catch (GlobalizeException e) {

      throw new ResolverException("Couldn't globalize Jar model", e);
    }

    if (!(globalModel instanceof URIReference)) {

      // Check that our node is a URIReference
      throw new ResolverException(
          "Graph parameter " + globalModel + " isn't a URI reference");
    }

    // Get the URI from the globalised node
    modelURI = ((URIReference) globalModel).getURI();

    assert modelURI != null;

    // Validate the URI
    if (!modelURI.getScheme().toLowerCase().startsWith("jar")) {

      throw new ResolverException(modelURI + " doesn't use the Jar: scheme");
    }

    // Container for our URL
    URL modelURL = null;

    try {

      // Convert the URI to a URL
      modelURL = modelURI.toURL();
    } catch (MalformedURLException malformedURLException) {

      throw new ResolverException(
          "Failed to convert the model's URI to a valid URL [" +
          modelURI +"]", malformedURLException);
    }

    try {
      return new JarContent(modelURL);
    }
    catch (URISyntaxException e) {
      throw new ResolverException(
        "Couldn't create JarContent from " + modelURL, e
      );
    }
  }
}