java - Parsing XML feed die with "Element is already used"

Question

I'm trying to parse an XML feed using SimpleXML in Android: http://backend.deviantart.com/rss.xml?type=deviation&q=by%3Aspyed+sort%3Atime+meta%3Aall

Sample here:

<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:atom="http://www.w3.org/2005/Atom" xmlns:creativeCommons="http://backend.userland.com/creativeCommonsRssModule" xmlns:media="http://search.yahoo.com/mrss/" version="2.0">
    <channel>
        <title>DeviantArt: spyed's</title>
        <link>http://www.deviantart.com/?order=5&amp;q=by%3Aspyed</link>
        <description>DeviantArt RSS for sort:time by:spyed</description>
        <language>en-us</language>
        <copyright>Copyright 2015, DeviantArt.com</copyright>
        <pubDate>Thu, 20 Aug 2015 07:45:31 PDT</pubDate>
        <generator>DeviantArt.com</generator>
        <docs>http://blogs.law.harvard.edu/tech/rss</docs>
        <atom:icon>http://st.deviantart.net/minish/touch-icons/android-192.png</atom:icon>
        <atom:link type="application/rss+xml" rel="self" href="http://backend.deviantart.com/rss.xml?q=sort%3Atime+by%3Aspyed&amp;type=deviation" />
        <atom:link rel="next" href="http://backend.deviantart.com/rss.xml?q=sort%3Atime+by%3Aspyed&amp;type=deviation&amp;offset=60" />
        <item>
            <title>Happy 15th Birthday!</title>
            <link>http://spyed.deviantart.com/journal/Happy-15th-Birthday-552416478</link>
            <guid isPermaLink="true">http://spyed.deviantart.com/journal/Happy-15th-Birthday-552416478</guid>
            <pubDate>Sun, 09 Aug 2015 01:41:54 PDT</pubDate>
            <media:title type="plain">Happy 15th Birthday!</media:title>
            <media:keywords />
            <media:rating>nonadult</media:rating>
            <media:category label="Personal">journals/personal</media:category>
            <media:credit role="author" scheme="urn:ebu">spyed</media:credit>
            <media:credit role="author" scheme="urn:ebu">http://a.deviantart.net/avatars/s/p/spyed.gif</media:credit>
            <media:copyright url="http://spyed.deviantart.com">Copyright 2015 spyed</media:copyright>
            <media:description type="html" />
            <media:content url="http://spyed.deviantart.com/journal/Happy-15th-Birthday-552416478" medium="document" />
            <media:text type="html">In April I wrote a post reflecting on my 15 years at DeviantArt, since the project began in April of 2000 and was launched to the public on August 7th. I went back and re-read what I wrote, and wow, speaking of audacious I'm pretty hardcore in this post. I write from my heart sometimes and then I hit post and that's that. So for our official 15th Birthday I wanted to re-share a link to that post:&lt;br /&gt;&lt;br /&gt;And then today, I wrote this reflection for you as a toast &amp;amp; thanks for all the llamas:&lt;br /&gt;&lt;br /&gt;Happy 15th Birthday DeviantArt! We are evolving, and soon we will be able to share exactly how you can be a part of our transformation, ensuring that the De</media:text>
            <description />
        </item>
        <item>
            <title>The Floor is Open</title>
            <link>http://spyed.deviantart.com/journal/The-Floor-is-Open-548845475</link>
            <guid isPermaLink="true">http://spyed.deviantart.com/journal/The-Floor-is-Open-548845475</guid>
            <pubDate>Sat, 25 Jul 2015 11:38:46 PDT</pubDate>
            <media:title type="plain">The Floor is Open</media:title>
            <media:keywords />
            <media:rating>nonadult</media:rating>
            <media:category label="Personal">journals/personal</media:category>
            <media:credit role="author" scheme="urn:ebu">spyed</media:credit>
            <media:credit role="author" scheme="urn:ebu">http://a.deviantart.net/avatars/s/p/spyed.gif</media:credit>
            <media:copyright url="http://spyed.deviantart.com">Copyright 2015 spyed</media:copyright>
            <media:description type="html" />
            <media:content url="http://spyed.deviantart.com/journal/The-Floor-is-Open-548845475" medium="document" />
            <media:text type="html">Happy Saturday! I'm hanging out at home, so I thought I'd have an open conversation. Post anything, I'll reply. It's about 11:30am, I'll be in front of this thing for two hours before I go to my god daughters 7th birthday party! Yay!&lt;br /&gt;&lt;br /&gt;If you're wondering what we're up to, check out the DeviantArt Timeline ( http://www.deviantart.com/timeline/ ) -- It might compel you to ask some questions. Or, if there's anything you've been wondering about, ask!&lt;br /&gt;&lt;br /&gt;Here's some food for thought to get you started about the overall state of DeviantArt:&lt;br /&gt;&lt;br /&gt;Our team focuses on two things that matter most to us, the first is our mission to Entertain, Inspire &amp;amp; Em</media:text>
            <description />
        </item>
        ... etc ....

but I'm getting the following error:

08-13 15:55:38.529: W/System.err(1437): org.simpleframework.xml.core.PersistenceException: Element 'title' is already used with @org.simpleframework.xml.Element(data=false, name=title, required=false, type=void) on field 'title' public java.lang.String com.example.feedreader.SimpleRss$Channel$RssItem.title at line 1

I noticed that there is a title tag in two different levels, but I'm not sure how to make the distinction in code.

Here's what I have:

@Root(name = "rss", strict = false)
public class SimpleRss implements FeedRoot {

    @Root(name = "channel")
    public static class Channel {

        @Element(name = "title", required = false)
        public String title = "";

        @Attribute(name = "href", required = false)
        @ElementList(entry = "link", inline = true, required = false)
        private List<String> links;

        @Element(name = "description", required = false)
        @Namespace(prefix = "")
        public String description = "";

        @Element(name = "pubDate", required = false)
        public String pubDate = "";

        @Element(name = "event_link", required = false)
        public String event_link = "";

        @Root(name = "item")
        public static class RssItem implements SimpleFeedItem {

            public String parent = "";
            public String feedUrl = null;
            public Date date = null;

            @Element(name = "title", required = false)
            public String title = "";

            @Element(name = "link", required = false)
            public String link = "";

            @Element(name = "event_link", required = false)
            public String event_link = "";

            @Element(name = "description", required = false)
            public String description = "";

            @Element(name = "pubDate", required = false)
            public String pubDate = "";

            @Path("enclosure")
            @Attribute(name = "url", required = false)
            public String enclosureUrl = "";

            @Path("enclosure")
            @Attribute(name = "type", required = false)
            public String enclosureType = "";

            @Override
            public String getTitle() {
                return title;
            }

            @Override
            public String getDescription() {
                return description;
            }

            @Override
            public String getLink() {
                return link;
            }

            @Override
            public String getEventLink() {
                return event_link;
            }

            @Override
            public String getAdditional() {
                return parent;
            }

            @Override
            public String getPubDate() {
                return pubDate;
            }

            @Override
            public String getFeedUrl() {
                return feedUrl;
            }

            @Override
            public void setFeedUrl(String url) {

                feedUrl = url;
            }

            @Override
            public void setDate(Date date) {
                this.date = date;
            }

            @Override
            public Date getDate() {
                return date;
            }

            @Override
            public String getPictureUrl() {
                if (DataUtils.isEmpty(enclosureType)) {
                    return null;
                } else if (SimpleFeedItem.SupportedFeedImageTypes
                        .contains(enclosureType.toLowerCase(Locale.ENGLISH))) {
                    return enclosureUrl;
                } else {
                    return null;
                }
            }

        }

        @ElementList(inline = true, required = false)
        public List<RssItem> rssItems = J.newArrayList();

    }

    @Element(name = "channel")
    public Channel channel;

    @Override
    public List<SimpleFeedItem> getItems() {
        List<SimpleFeedItem> items = J.newArrayList();

        if (channel != null && channel.rssItems != null) {
            for (RssItem item : channel.rssItems) {
                String title = channel.title;
                if (title == null) {
                    title = "";
                }
                item.parent = title.intern();
                items.add(item);
            }
        }
        return items;
    }

    @Override
    public String getTitle() {
        if (channel == null) {
            return "";
        } else {
            return channel.title;
        }
    }

}

I've tried commenting out the

@Element(name = "title", required = false)
public String title = "";

in the Channel class and I get the same error. Also if I just rename it.

If I do the same with the one in the RssItem class however, it will work but I don't get the titles for the items.

Thanks!

Answer 1

This fixes the problem:

Remove this:

@Element(name = "title", required = false)

Replace with:

//inside the inner class RssItem
@Path("title")
@Text(required=false)
public String title = "";

This should be repeated for any other field that gets the exception.