de.nava.informa.exporters.RSS_0_91_Exporter.java Source code

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Here is the source code for de.nava.informa.exporters.RSS_0_91_Exporter.java

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//
// Informa -- RSS Library for Java
// Copyright (c) 2002 by Niko Schmuck
//
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// which accompanies this distribution, and is available at
// http://www.eclipse.org/legal/epl-v10.html
//

package de.nava.informa.exporters;

import de.nava.informa.core.ChannelExporterIF;
import de.nava.informa.core.ChannelIF;
import de.nava.informa.core.ItemIF;
import de.nava.informa.utils.ParserUtils;
import org.jdom2.DocType;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;

import java.io.*;
import java.util.Collection;
import java.util.Iterator;

/**
 * A channel exporter that can write channel objects out into the
 * interchange syntax defined by RSS 0.91.
 */
public class RSS_0_91_Exporter implements ChannelExporterIF {

    public static final String PUBLIC_ID = "-//Netscape Communications//DTD RSS 0.91//EN";
    public static final String SYSTEM_ID = "http://my.netscape.com/publish/formats/rss-0.91.dtd";
    public static final String RSS_VERSION = "0.91";

    private Writer writer;
    private String encoding;

    /**
     * Creates a channel exporter bound to the file given in the
     * argument. The channel will be written out in the UTF-8 encoding.
     *
     * @param filename - The name of the file to which the channel object
     *                 is to be written.
     */
    public RSS_0_91_Exporter(String filename) throws IOException {
        this(new File(filename), "utf-8");
    }

    /**
     * Creates a channel exporter bound to the file given in the
     * argument. The channel will be written out in the UTF-8 encoding.
     *
     * @param file - The file object to which the channel object is
     *             to be written.
     */
    public RSS_0_91_Exporter(File file) throws IOException {
        this(file, "utf-8");
    }

    /**
     * Creates a channel exporter bound to the file given in the
     * arguments.
     *
     * @param file     - The file object to which the channel object is
     *                 to be written.
     * @param encoding - The character encoding to write the channel
     *                 object in.
     */
    public RSS_0_91_Exporter(File file, String encoding) throws IOException {
        this.writer = new OutputStreamWriter(new FileOutputStream(file), encoding);
        this.encoding = encoding;
    }

    /**
     * Creates a channel exporter bound to the Writer given in
     * the arguments.
     *
     * @param writer   - The Writer to which the channel object is to be
     *                 written.
     * @param encoding - The character encoding the Writer writes in.
     */
    public RSS_0_91_Exporter(Writer writer, String encoding) {
        this.writer = writer;
        this.encoding = encoding;
    }

    // ------------------------------------------------------------
    // implementation of ChannelExporterIF interface
    // ------------------------------------------------------------

    public void write(ChannelIF channel) throws IOException {
        if (writer == null) {
            throw new RuntimeException("No writer has been initialized.");
        }

        // create XML outputter with indent: 2 spaces, print new lines.
        Format format = Format.getPrettyFormat();
        format.setEncoding(encoding);
        XMLOutputter outputter = new XMLOutputter(format);

        // ----
        Element rootElem = new Element("rss");
        rootElem.setAttribute("version", RSS_VERSION);
        Element channelElem = new Element("channel");

        channelElem.addContent(new Element("title").setText(channel.getTitle()));

        channelElem.addContent(new Element("description").setText(channel.getDescription()));
        if (channel.getSite() != null) {
            channelElem.addContent(new Element("link").setText(channel.getSite().toString()));
        }
        if (channel.getLanguage() != null) {
            channelElem.addContent(new Element("language").setText(channel.getLanguage()));
        }

        Collection items = channel.getItems();
        Iterator it = items.iterator();
        while (it.hasNext()) {
            channelElem.addContent(getItemElement((ItemIF) it.next()));
        }

        // export channel image
        if (channel.getImage() != null) {
            Element imgElem = new Element("image");
            imgElem.addContent(new Element("title").setText(channel.getImage().getTitle()));
            imgElem.addContent(new Element("url").setText(channel.getImage().getLocation().toString()));
            imgElem.addContent(new Element("link").setText(channel.getImage().getLink().toString()));
            imgElem.addContent(new Element("height").setText("" + channel.getImage().getHeight()));
            imgElem.addContent(new Element("width").setText("" + channel.getImage().getWidth()));
            imgElem.addContent(new Element("description").setText(channel.getImage().getDescription()));
            channelElem.addContent(imgElem);
        }

        // TODO: add exporting textinput field
        //     if (channel.getTextInput() != null) {
        //       channelElem.addContent(channel.getTextInput().getElement());
        //     }

        if (channel.getCopyright() != null) {
            channelElem.addContent(new Element("copyright").setText(channel.getCopyright()));
        }

        // we have all together for the channel definition
        rootElem.addContent(channelElem);
        // ---
        DocType docType = new DocType("rss", PUBLIC_ID, SYSTEM_ID);
        Document doc = new Document(rootElem, docType);
        outputter.output(doc, writer);
    }

    protected Element getItemElement(ItemIF item) {
        Element itemElem = new Element("item");
        itemElem.addContent(new Element("title").setText(item.getTitle()));
        if (item.getLink() != null) {
            itemElem.addContent(new Element("link").setText(item.getLink().toString()));
        }
        if (item.getDescription() != null) {
            itemElem.addContent(new Element("description").setText(item.getDescription()));
        }
        if (item.getDate() != null) {
            itemElem.addContent(new Element("pubDate").setText(ParserUtils.formatDate(item.getDate())));
        }
        return itemElem;
    }

}