DomContentProvider.java

   1 package org.argeo.cms.acr.xml;
   2
   3 import java.io.IOException;
   4 import java.io.OutputStream;
   5 import java.util.ArrayList;
   6 import java.util.Collections;
   7 import java.util.Iterator;
   8 import java.util.List;
   9
  10 import javax.xml.namespace.NamespaceContext;
  11 import javax.xml.transform.TransformerFactory;
  12 import javax.xml.xpath.XPath;
  13 import javax.xml.xpath.XPathConstants;
  14 import javax.xml.xpath.XPathExpressionException;
  15 import javax.xml.xpath.XPathFactory;
  16
  17 import org.argeo.api.acr.Content;
  18 import org.argeo.api.acr.ContentNotFoundException;
  19 import org.argeo.api.acr.CrName;
  20 import org.argeo.api.acr.NamespaceUtils;
  21 import org.argeo.api.acr.spi.ContentProvider;
  22 import org.argeo.api.acr.spi.ProvidedContent;
  23 import org.argeo.api.acr.spi.ProvidedSession;
  24 import org.argeo.cms.acr.CmsContentRepository;
  25 import org.argeo.cms.acr.ContentUtils;
  26 import org.w3c.dom.Document;
  27 import org.w3c.dom.Element;
  28 import org.w3c.dom.NodeList;
  29
  30 public class DomContentProvider implements ContentProvider, NamespaceContext {
  31         private final Document document;
  32
  33         // XPath
  34         // TODO centralise in some executor?
  35         private final ThreadLocal<XPath> xPath;
  36
  37         private TransformerFactory transformerFactory;
  38
  39         private String mountPath;
  40
  41         public DomContentProvider(String mountPath, Document document) {
  42                 this.mountPath = mountPath;
  43                 this.document = document;
  44                 this.document.normalizeDocument();
  45
  46                 transformerFactory = TransformerFactory.newInstance();
  47
  48                 XPathFactory xPathFactory = XPathFactory.newInstance();
  49                 xPath = new ThreadLocal<>() {
  50
  51                         @Override
  52                         protected XPath initialValue() {
  53                                 // TODO set the document as namespace context?
  54                                 XPath res = xPathFactory.newXPath();
  55                                 res.setNamespaceContext(DomContentProvider.this);
  56                                 return res;
  57                         }
  58                 };
  59         }
  60
  61         @Override
  62         public ProvidedContent get(ProvidedSession session, String relativePath) {
  63                 if ("".equals(relativePath))
  64                         return new DomContent(session, this, document.getDocumentElement());
  65
  66                 NodeList nodes = findContent(relativePath);
  67                 if (nodes.getLength() > 1)
  68                         throw new IllegalArgumentException("Multiple content found for " + relativePath + " under " + mountPath);
  69                 if (nodes.getLength() == 0)
  70                         throw new ContentNotFoundException(session, mountPath + "/" + relativePath,
  71                                         "Path " + relativePath + " under " + mountPath + " was not found");
  72                 Element element = (Element) nodes.item(0);
  73                 return new DomContent(session, this, element);
  74         }
  75
  76         protected NodeList findContent(String relativePath) {
  77                 if (relativePath.startsWith("/"))
  78                         throw new IllegalArgumentException("Relative path cannot start with /");
  79                 String xPathExpression = '/' + relativePath;
  80                 if (ContentUtils.SLASH_STRING.equals(mountPath)) // repository root
  81                         xPathExpression = "/" + CrName.root.qName() + xPathExpression;
  82                 try {
  83                         NodeList nodes = (NodeList) xPath.get().evaluate(xPathExpression, document, XPathConstants.NODESET);
  84                         return nodes;
  85                 } catch (XPathExpressionException e) {
  86                         throw new IllegalArgumentException("XPath expression " + xPathExpression + " cannot be evaluated", e);
  87                 }
  88
  89         }
  90
  91         @Override
  92         public boolean exists(ProvidedSession session, String relativePath) {
  93                 if ("".equals(relativePath))
  94                         return true;
  95                 NodeList nodes = findContent(relativePath);
  96                 return nodes.getLength() != 0;
  97         }
  98
  99         public void persist(ProvidedSession session) {
 100                 if (mountPath != null) {
 101                         Content mountPoint = session.getMountPoint(mountPath);
 102                         try (OutputStream out = mountPoint.open(OutputStream.class)) {
 103                                 CmsContentRepository contentRepository = (CmsContentRepository) session.getRepository();
 104                                 contentRepository.writeDom(document, out);
 105                         } catch (IOException e) {
 106                                 throw new IllegalStateException("Cannot persist " + mountPath, e);
 107                         }
 108                 }
 109         }
 110
 111         @Override
 112         public String getMountPath() {
 113                 return mountPath;
 114         }
 115
 116         public void registerPrefix(String prefix, String namespace) {
 117                 DomUtils.addNamespace(document.getDocumentElement(), prefix, namespace);
 118         }
 119
 120         /*
 121          * NAMESPACE CONTEXT
 122          */
 123         @Override
 124         public String getNamespaceURI(String prefix) {
 125                 String namespaceURI = NamespaceUtils.getStandardNamespaceURI(prefix);
 126                 if (namespaceURI != null)
 127                         return namespaceURI;
 128                 return document.lookupNamespaceURI(prefix);
 129         }
 130
 131         @Override
 132         public String getPrefix(String namespaceURI) {
 133                 String prefix = NamespaceUtils.getStandardPrefix(namespaceURI);
 134                 if (prefix != null)
 135                         return prefix;
 136                 return document.lookupPrefix(namespaceURI);
 137         }
 138
 139         @Override
 140         public Iterator<String> getPrefixes(String namespaceURI) {
 141                 List<String> res = new ArrayList<>();
 142                 res.add(getPrefix(namespaceURI));
 143                 return Collections.unmodifiableList(res).iterator();
 144         }
 145
 146         TransformerFactory getTransformerFactory() {
 147                 return transformerFactory;
 148         }
 149
 150 }