/*

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:

*

*/

package com.nokia.microedition.m2g.connection;

import java.io.*;

import javax.microedition.io.*;

import javax.microedition.m2g.ExternalResourceHandler;

import javax.microedition.m2g.*;

/**

* <p>This private class is the default resource handler

* used to load external resources that are referenced

* within a ScalableImage, namely within a SVG document in the case of SVG.

* The default resource handler will be used by the platform in the following cases:

*   - if the MIDlet has not explicitly set its own handler to load external resources

*   - if the resource handler specified by the MIDlet is not able to load the

*     external resources (i.e. the MIDlet's SVGResourceHandle.getExternalResource()

*     returns null).</p>

* @see javax.microedition.m2g.ExternalResourceHandler

*/

public class M2GDefaultExternalResourceHandler implements ExternalResourceHandler

{

    /*

     * According to RFC 2396, the rules for determening the base URI can be summarized

     * as follows (highest priority to lowest):

     * 1.The base URI is embedded in the document's content.

     * 2.The base URI is that of the encapsulating document.

     * 3.The base URI is the URI used to retrieve  the entity.

     * 4.The base URI is defined by the context of the application

     *

     * Note that in the case of the M2GDefaultExternalResourceHandler  4. is not

     * applicable.

     */

    //--------------------------------------------------

    // VARIABLES

    //--------------------------------------------------

    private M2GUrlTokenizer iTokenizer = null;

    //--------------------------------------------------

    // METHODS

    //--------------------------------------------------

    /**

     * This constructor is used to create a default resource handler that can

     * load resources from absolute URLs and from URLs that are relative

     * to the aUrl.

     * NOTE: This handler will not be allowed to load resources from the application's

     * jar file.

     *

     * @param aUrl The already validated url used to load the svg document

     */

    M2GDefaultExternalResourceHandler(String aUrl)

    {

        if (aUrl == null || aUrl.equals(""))

        {

            iTokenizer = new M2GUrlTokenizer();

        }

        else

        {

            iTokenizer = new M2GUrlTokenizer(aUrl);

        }

    }

    /**

     * This constructor is used to create a default resource handler that can

     * load external resources from fully qualified URLs ONLY. Any relative URL

     * will be considered to be a link to a resource within the application's jar file.

     */

    M2GDefaultExternalResourceHandler()

    {

        this(null);

    }

    /**

      * This method is invoked when an external resource is required by the underlying implementation.

      * When the request is completed by the implementation of this handler, a notification

      * must be sent to the SVG engine through the requestCompleted() method of <code>ScalableImage</code>.

      * To get a synchronous behaviour, requestCompleted() can be called in the implementation

      * of requestResource. If called later, rendering the document before

      * completing all the requests will just display the currently available content.

      * Once the request is completed, the image will have to be redrawn to reflect the newly

      * available data.

      * For more details on required resources, please refer to the <code>externalResourcesRequired</code>

      * attribute description in the SVG specification.

      *

      * @param image image that originated the external data request

      * @param URL the an absolute or a relative URL for the external resource + drm mode

      */

    public void requestResource(ScalableImage aImage, String aUrl)

    {

        M2GConnectionProxy proxy = null;

        /* IMPLEMENTATION NOTE:

         * The default resource handler assumes that if there is an embedded base URL within the

         * document then is upon the svg engine to provide the absolute URL.

         * If the given URL is a relative URL then this handler will attempt to use as a base URL

         * to retrieve the containing svg document. However, if the document's base

         * URL is null then this handler will assume the given relative URL to be a file name

         * within the application's jar file.

         */

        try

        {

            // NOTE: if exception is thrown during the resolveExternalResourceUrl() call then

            // the requestCompleted should be called again with a null input stream.

            proxy = M2GConnectionFactory.resolveExternalResourceUrl(iTokenizer, aUrl);

            aImage.requestCompleted(aUrl, proxy.getInputStream());

        }

        catch (Exception e)

        {

            // e.printStackTrace();

            // The requestCompleted() failed

            try

            {

                aImage.requestCompleted(aUrl, null);

            }

            catch (Exception ee)

            {

                // ee.printStackTrace();

            }

        }

        // Close streams

        finally

        {

            try

            {

                if (proxy != null)

                {

                    proxy.close();

                }

            }

            catch (Exception e)

            {

                // e.printStackTrace();

            }

        }

    }

}