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POXPATH in Java: parent node missing
 

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    <p>I have the following XML structure:</p> <pre><code>&lt;map name="testmap"&gt; &lt;definitions&gt; &lt;tile name="ground"&gt; &lt;!-- a normal tile that has no special obstacles --&gt; &lt;centralObstacle&gt;ground&lt;/centralObstacle&gt; &lt;neighbourObstacles&gt; &lt;north&gt;&lt;/north&gt; &lt;east&gt;&lt;/east&gt; &lt;south&gt;&lt;/south&gt; &lt;west&gt;&lt;/west&gt; &lt;/neighbourObstacles&gt; &lt;/tile&gt; &lt;tile name="wallE"&gt; &lt;!-- a ground tile with a wall obstacle at the east--&gt; &lt;centralObstacle&gt;ground&lt;/centralObstacle&gt; &lt;neighbourObstacles&gt; &lt;north&gt;&lt;/north&gt; &lt;east&gt;wall&lt;/east&gt; &lt;south&gt;&lt;/south&gt; &lt;west&gt;&lt;/west&gt; &lt;/neighbourObstacles&gt; &lt;/tile&gt; &lt;/definitions&gt; &lt;/map&gt; </code></pre> <p>And I would like to query it with XPATH. What I would like to do is get all the tile Nodes and then iterate over them to get all their names and other relevant information (using different XPATH queries).</p> <p>Because XPATH expressions are to be ran on a Document, I have used the following <code>nodeListToDoc()</code> function, provided in <a href="https://stackoverflow.com/questions/5786936/create-xml-document-using-nodelist">this</a> answer to convert the result of an XPATH query (a NodeList) to a Document. This way I can first get all the Tiles, then iterate over them to get Tile specific information.</p> <pre><code>private Document nodeListToDoc(NodeList nodes) throws ParserConfigurationException { Document newXmlDocument = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument(); Element root = newXmlDocument.createElement("root"); newXmlDocument.appendChild(root); for (int i = 0; i &lt; nodes.getLength(); i++) { Node node = nodes.item(i); Node copyNode = newXmlDocument.importNode(node, true); root.appendChild(copyNode); } return newXmlDocument; } </code></pre> <p>What I first do is parse the file to a Document and then run the query to get a NodeList that contains all my Tiles. When I run the query <code>//definitions/tile</code> I get a NodeList containing two Node items (I have verified this), which is correct. The result of applying <code>nodeListToDoc()</code> looks like this.</p> <pre><code> &lt;?xml version="1.0" encoding="UTF-16"?&gt; &lt;root&gt;&lt;tile name="ground"&gt; &lt;!-- a normal tile that has no special obstacles --&gt; &lt;centralObstacle&gt;ground&lt;/centralObstacle&gt; &lt;neighbourObstacles&gt; &lt;north/&gt; &lt;east/&gt; &lt;south/&gt; &lt;west/&gt; &lt;/neighbourObstacles&gt; &lt;/tile&gt;&lt;tile name="wallE"&gt; &lt;!-- a ground tile with a wall obstacle at the east--&gt; &lt;centralObstacle&gt;ground&lt;/centralObstacle&gt; &lt;neighbourObstacles&gt; &lt;north/&gt; &lt;east&gt;wall&lt;/east&gt; &lt;south/&gt; &lt;west/&gt; &lt;/neighbourObstacles&gt; &lt;/tile&gt;&lt;/root&gt; </code></pre> <p>So far so good. Now things go bad. I want to iterate over the two nodes, make a NodeList of them, convert that NodeList to a Document and then run some queries over them. One of the queries is get the name of every tile. I thought the following code piece would do the trick:</p> <pre><code> for (int i = 0; i &lt; nodes.getLength(); i++) { // iterate over the two nodes NodeList tile = (NodeList) nodes.item(i); // create a nodelist containing only the first node Document attrdoc = nodeListToDoc(tile); // convert it to a document } </code></pre> <p>However, when I print the resulting tree that attrdoc represents, I get, for the first iteration, the following result:</p> <pre><code>&lt;?xml version="1.0" encoding="UTF-16"?&gt; &lt;root&gt; &lt;!-- a normal tile that has no special obstacles --&gt; &lt;centralObstacle&gt;ground&lt;/centralObstacle&gt; &lt;neighbourObstacles&gt; &lt;north/&gt; &lt;east/&gt; &lt;south/&gt; &lt;west/&gt; &lt;/neighbourObstacles&gt; &lt;/root&gt; </code></pre> <p>This is incorrect. The child of the root element should be tile? Where did this element go? </p>
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    1. CO`Because XPATH expressions are to be ran on a Document` why do you think so? Which API do you use? `XPath.evaluate(String, Object)` can accept `NodeList` as a second argument (which is a context for an XPath lookup)
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      1. POXPATH in Java: parent node missing
      1. USAndrey Balaguta
 

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