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| − | <div style="margin:5px;float:right;border:1px solid #000000;padding:5px">__TOC__</div>
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| − | =Dynamic JAXB: Flickr Example=
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| − | This example will demonstrate how to use MOXy's Dynamic JAXB features to work with public JSON and XML feeds, without having to create concrete Java classes. The following concepts are demonstrated:
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| − |
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| − | * Mapping to JSON and XML data without writing or generating concrete Java classes
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| − | * Using multiple EclipseLink binding files to modularize your metadata
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| − | * Bootstrapping a DynamicJAXBContext from multiple EclipseLink metadata files
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| − | * Using a single DynamicJAXBContext to read both JSON and XML data
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| − | * Using DynamicEntity APIs to interact with mapped data
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| − | * Using UnmarshallerProperties.JSON_INCLUDE_ROOT to read JSON that does not have a root element
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| − | * Using Marshaller.JAXB_FRAGMENT to omit the XML preamble when writing
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| − | * Using XPath Predicate mapping to map to an element based on an attribute value
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| − | This example uses MOXy to read a JSON stream from Reddit, an XML stream from Flickr, and uses the data from both to create an HTML file.
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| − | ==Running the Example==
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| − | The full code for this example is available under [http://git.eclipse.org/c/eclipselink/examples.git/tree/moxy/twitter moxy/dynamic/flickr] in the EclipseLink Examples Git repository:
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| − | <div style="width:50%">
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| − | <source lang="text">
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| − | git clone git://git.eclipse.org/gitroot/eclipselink/examples.git
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| − | </source>
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| − | </div>
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| − |
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| − | To run the example, just execute Maven:
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| − | <source lang="text">
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| − | mvn
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| − | </source>
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| − | This will connect to the Internet to read the JSON and XML feeds, and will launch the system browser on the generated HTML file.
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| − | {{note|Proxy Connections|If you require a proxy server to access the Internet, check the <code><systemProperties></code> section of <code>pom.xml</code>.}}
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| − | ==Getting JSON from Reddit==
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| − | Reddit provides a public JSON feed using the following URL format:
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| − | <code>
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| − | http://www.reddit.com/r/science/top/.json?sort=top&t=day&limit=5
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| − | </code>
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| − | This will return us JSON in the [[#Reddit JSON Format|following format]]. For this example, we are primarily interested in the '''title''' and '''url''' fields of '''data/children/data'''.
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| − | ==Mapping to Reddit JSON==
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| − | The EclipseLink metadata that defines our mappings to the JSON output is stored in the '''bindings-reddit.xml''' file. We define a '''RedditResults''' class that will hold a collection of '''RedditPost''' objects. Each '''RedditPost''' maps to the '''title''' and '''url''' returned by Reddit.
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| − |
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| − | <source lang="xml">
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| − | <java-types>
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| − | <java-type name="eclipselink.example.moxy.dynamic.flickr.RedditResults">
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| − | <xml-root-element/>
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| − | <java-attributes>
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| − | <xml-element java-attribute="posts" xml-path="data/children" container-type="java.util.ArrayList"
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| − | type="eclipselink.example.moxy.dynamic.flickr.RedditPost" />
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| − | </java-attributes>
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| − | </java-type>
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| − |
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| − | <java-type name="eclipselink.example.moxy.dynamic.flickr.RedditPost">
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| − | <java-attributes>
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| − | <xml-element java-attribute="title" xml-path="data/title/text()" type="java.lang.String"/>
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| − | <xml-element java-attribute="url" xml-path="data/url/text()" type="java.lang.String"/>
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| − | </java-attributes>
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| − | </java-type>
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| − |
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| − | </java-types>
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| − | </source>
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| − |
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| − |
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| − | ==Getting XML from Flickr==
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| − |
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| − | Flickr provides a public XML feed using the following URL format:
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| − |
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| − | <code>
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| − | http://api.flickr.com/services/feeds/photos_public.gne?tags=science
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| − | </code>
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| − |
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| − | This will return us XML in the [[#Flickr XML Format|following format]]. For each '''entry''', we want to locate the '''link''' element that has '''@type='image/jpeg'''', and extract the '''href''' attribute, pointing to the actual image.
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| − |
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| − |
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| − | ==Mapping to Flickr XML==
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| − |
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| − | The EclipseLink metadata that defines our mappings to Flickr's XML output is stored in the '''bindings-flickr.xml''' file. We define a '''FlickrResults''' class that will hold a collection of '''FlickrItem''' objects, as well as a '''description''' of the search being performed. Each '''FlickrItem''' simply contains a URL string pointing to an image file.
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| − |
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| − | <source lang="xml">
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| − | <xml-schema element-form-default="QUALIFIED" namespace="http://www.w3.org/2005/Atom"/>
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| − |
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| − | <java-types>
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| − |
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| − | <java-type name="eclipselink.example.moxy.dynamic.flickr.FlickrResults">
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| − | <xml-root-element name="feed"/>
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| − | <java-attributes>
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| − | <xml-element java-attribute="description" xml-path="title/text()" type="java.lang.String"/>
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| − | <xml-element java-attribute="items" xml-path="entry" container-type="java.util.ArrayList"
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| − | type="eclipselink.example.moxy.dynamic.flickr.FlickrItem"/>
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| − | </java-attributes>
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| − | </java-type>
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| − |
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| − | <java-type name="eclipselink.example.moxy.dynamic.flickr.FlickrItem">
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| − | <java-attributes>
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| − | <xml-attribute java-attribute="imageUrl" xml-path="link[@type='image/jpeg']/@href" type="java.lang.String"/>
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| − | </java-attributes>
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| − | </java-type>
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| − |
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| − | </java-types>
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| − | </source>
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| − |
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| − |
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| − | ==Appendix - Data Formats==
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| − |
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| − | ===Reddit JSON Format===
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| − |
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| − | <source lang="text">
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| − | {
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| − | "kind":"Listing",
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| − | "data":{
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| − | "modhash":"qdohhwkxss9091dc13eed91db333b619420a787aa2a39b3982",
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| − | "children":[
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| − | {
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| − | "kind":"t3",
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| − | "data":{
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| − | "domain":"news.mongabay.com",
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| − | "banned_by":null,
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| − | "media_embed":{
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| − |
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| − | },
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| − | "subreddit":"science",
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| − | "selftext_html":null,
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| − | "selftext":"",
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| − | "likes":null,
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| − | "link_flair_text":null,
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| − | "id":"1f5jv3",
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| − | "clicked":false,
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| − | "title":"Plants re-grow after 500 years under the ice",
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| − | "media":null,
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| − | "score":2665,
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| − | "approved_by":null,
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| − | "over_18":false,
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| − | "hidden":false,
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| − | "thumbnail":"",
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| − | "subreddit_id":"t5_mouw",
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| − | "edited":false,
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| − | "link_flair_css_class":null,
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| − | "author_flair_css_class":null,
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| − | "downs":5569,
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| − | "saved":false,
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| − | "is_self":false,
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| − | "permalink":"/r/science/comments/1f5jv3/plants_regrow_after_500_years_under_the_ice/",
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| − | "name":"t3_1f5jv3",
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| − | "created":1369712639.0,
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| − | "url":"http://news.mongabay.com/2013/0527-dimitrova-ice-plants.html",
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| − | "author_flair_text":null,
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| − | "author":"soyuz-capsule",
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| − | "created_utc":1369683839.0,
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| − | "ups":8234,
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| − | "num_comments":178,
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| − | "num_reports":null,
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| − | "distinguished":null
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| − | }
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| − | },
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| − | ...
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| − | </source>
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| − |
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| − |
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| − | ===Flickr XML Format===
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| − |
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| − | <source lang="text">
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| − | <?xml version="1.0" encoding="UTF-8"?>
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| − | <feed xmlns="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:flickr="urn:flickr:user" xmlns:media="http://search.yahoo.com/mrss/">
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| − | <title>Recent Uploads tagged science</title>
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| − | <link rel="self" href="http://api.flickr.com/services/feeds/photos_public.gne?tags=science" />
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| − | <link rel="alternate" type="text/html" href="http://www.flickr.com/photos/tags/science/" />
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| − | <id>tag:flickr.com,2005:/photos/public/tagged/all/science</id>
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| − | <icon>http://l.yimg.com/g/images/buddyicon.gif</icon>
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| − | <subtitle />
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| − | <updated>2013-05-28T17:54:28Z</updated>
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| − | <generator uri="http://www.flickr.com/">Flickr</generator>
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| − | <entry>
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| − | <title>Space Shuttle Endeavour</title>
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| − | <link rel="alternate" type="text/html" href="http://www.flickr.com/photos/d3capmode/8869663050/" />
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| − | <id>tag:flickr.com,2005:/photo/8869663050</id>
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| − | <published>2013-05-28T17:54:28Z</published>
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| − | <updated>2013-05-28T17:54:28Z</updated>
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| − | <flickr:date_taken>2013-05-26T14:11:25-08:00</flickr:date_taken>
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| − | <dc:date.Taken>2013-05-26T14:11:25-08:00</dc:date.Taken>
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| − | <content type="html"><p><a href="http://www.flickr.com/people/d3capmode/">Jason Scheier</a> posted a photo:</content>
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| − | <author>
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| − | <name>Jason Scheier</name>
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| − | <uri>http://www.flickr.com/people/d3capmode/</uri>
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| − | <flickr:nsid>49842342@N07</flickr:nsid>
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| − | <flickr:buddyicon>http://farm6.staticflickr.com/5452/buddyicons/49842342@N07.jpg?1369198532#49842342@N07</flickr:buddyicon>
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| − | </author>
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| − | <link rel="enclosure" type="image/jpeg" href="http://farm8.staticflickr.com/7366/8869663050_e0aa1331fe_b.jpg" />
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| − | <category term="park" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="love" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="los" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="memorial" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="day" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="control" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="angeles" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="space" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="engineering" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="center" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="science" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="nasa" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="exposition" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="shuttle" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="mission" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="jpl" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="starship" scheme="http://www.flickr.com/photos/tags/" />
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| − | <category term="endeavour" scheme="http://www.flickr.com/photos/tags/" />
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| − | </entry>
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| − | <entry>
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| − | ...
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| − | </source>
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