DomContentProvider.java

   1 package org.argeo.cms.gcr.xml;
   2
   3 import java.util.ArrayList;
   4 import java.util.Collections;
   5 import java.util.Iterator;
   6 import java.util.List;
   7
   8 import javax.xml.namespace.NamespaceContext;
   9 import javax.xml.xpath.XPath;
  10 import javax.xml.xpath.XPathConstants;
  11 import javax.xml.xpath.XPathExpressionException;
  12 import javax.xml.xpath.XPathFactory;
  13
  14 import org.argeo.api.gcr.Content;
  15 import org.argeo.api.gcr.ContentNotFoundException;
  16 import org.argeo.api.gcr.spi.ContentProvider;
  17 import org.argeo.api.gcr.spi.ProvidedSession;
  18 import org.w3c.dom.Document;
  19 import org.w3c.dom.Element;
  20 import org.w3c.dom.NodeList;
  21
  22 public class DomContentProvider implements ContentProvider, NamespaceContext {
  23         private Document document;
  24
  25         // XPath
  26         // TODO centralise in some executor?
  27         private final ThreadLocal<XPath> xPath;
  28
  29         public DomContentProvider(Document document) {
  30                 this.document = document;
  31                 this.document.normalizeDocument();
  32                 XPathFactory xPathFactory = XPathFactory.newInstance();
  33                 xPath = new ThreadLocal<>() {
  34
  35                         @Override
  36                         protected XPath initialValue() {
  37                                 // TODO set the document as namespace context?
  38                                 XPath res= xPathFactory.newXPath();
  39                                 res.setNamespaceContext(DomContentProvider.this);
  40                                 return res;
  41                         }
  42                 };
  43         }
  44
  45 //      @Override
  46 //      public Content get() {
  47 //              return new DomContent(this, document.getDocumentElement());
  48 //      }
  49
  50 //      public Element createElement(String name) {
  51 //              return document.createElementNS(null, name);
  52 //
  53 //      }
  54
  55         @Override
  56         public Content get(ProvidedSession session, String mountPath, String relativePath) {
  57                 if ("".equals(relativePath))
  58                         return new DomContent(session, this, document.getDocumentElement());
  59                 if (relativePath.startsWith("/"))
  60                         throw new IllegalArgumentException("Relative path cannot start with /");
  61
  62                 String xPathExpression = '/' + relativePath;
  63                 if ("/".equals(mountPath))
  64                         xPathExpression = "/cr:root" + xPathExpression;
  65                 try {
  66                         NodeList nodes = (NodeList) xPath.get().evaluate(xPathExpression, document, XPathConstants.NODESET);
  67                         if (nodes.getLength() > 1)
  68                                 throw new IllegalArgumentException(
  69                                                 "Multiple content found for " + relativePath + " under " + mountPath);
  70                         if (nodes.getLength() == 0)
  71                                 throw new ContentNotFoundException("Path " + relativePath + " under " + mountPath + " was not found");
  72                         Element element = (Element) nodes.item(0);
  73                         return new DomContent(session, this, element);
  74                 } catch (XPathExpressionException e) {
  75                         throw new IllegalArgumentException("XPath expression " + xPathExpression + " cannot be evaluated", e);
  76                 }
  77         }
  78
  79         /*
  80          * NAMESPACE CONTEXT
  81          */
  82         @Override
  83         public String getNamespaceURI(String prefix) {
  84                 return document.lookupNamespaceURI(prefix);
  85         }
  86
  87         @Override
  88         public String getPrefix(String namespaceURI) {
  89                 return document.lookupPrefix(namespaceURI);
  90         }
  91
  92         @Override
  93         public Iterator<String> getPrefixes(String namespaceURI) {
  94                 List<String> res = new ArrayList<>();
  95                 res.add(getPrefix(namespaceURI));
  96                 return Collections.unmodifiableList(res).iterator();
  97         }
  98
  99 }