net.dancioi.jcsphotogallery.client.model.ReadXMLGeneric.java Source code

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Here is the source code for net.dancioi.jcsphotogallery.client.model.ReadXMLGeneric.java

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/*   
 *    File    : AlbumsDataAccess.java
 * 
 *    Copyright (C) 2011-2011 Daniel Cioi <dan@dancioi.net>
 *                              
 *   www.dancioi.net/projects/Jcsphotogallery
 *
 *   This file is part of Jcsphotogallery.
 *
 *  Jcsphotogallery 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  Jcsphotogallery 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Jcsphotogallery.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */
package net.dancioi.jcsphotogallery.client.model;

import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.xml.client.Document;
import com.google.gwt.xml.client.Element;
import com.google.gwt.xml.client.XMLParser;
import com.google.gwt.xml.client.impl.DOMParseException;

/**
 * Generic class for Read XML files.
 * 
 * @author Daniel Cioi <dan@dancioi.net>
 * @version $Revision$ Last modified: $Date$, by: $Author$
 */
public abstract class ReadXMLGeneric extends ElementXML {

    /**
     * Gets the XML file from http server.
     */
    public void readXmlFile(final String file, final int flag) {
        RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, file);
        try {
            requestBuilder.sendRequest(null, new RequestCallback() {
                public void onError(Request request, Throwable exception) {
                    showException("Error sending request");
                }

                public void onResponseReceived(Request request, Response response) {
                    if (200 == response.getStatusCode()) {
                        parseXMLString(response.getText(), flag); // careful here, this is an asynchronous callback.
                    } else if (404 == response.getStatusCode()) {
                        showException("File " + file + " not found on server. Wrong name or missing.");
                    } else {
                        showException("Other exception on GET the " + file + " file");
                    }
                }
            });
        } catch (RequestException ex) {
            new ReadException("Error sending request");
        }
    }

    /*
     * Parse the xml file.
     * 
     * @param file
     * 
     * @return element
     */
    private void parseXMLString(String xmlText, int flag) {
        Document document = null;
        try {
            document = XMLParser.parse(xmlText);

            Element element = document.getDocumentElement();
            XMLParser.removeWhitespace(element);

            if (flag == ReadXML.FLAG_ALBUMS)
                albumsCallback(element);
            else if (flag == ReadXML.FLAG_ALBUMPHOTOS)
                albumPhotosCallback(element);
        } catch (DOMParseException de) {
            showException("File parse exception. Use a XML editor to avoid syntax errors in xml file.");
        }
    }

    private void showException(String msg) {
        new ReadException(msg);
    }

    public abstract void albumsCallback(Element element);

    public abstract void albumPhotosCallback(Element element);

}