Package org.olat.modules.cp

Source Code of org.olat.modules.cp.CPManifestTreeModel

/**
* OLAT - Online Learning and Training<br>
* http://www.olat.org
* <p>
* Licensed under the Apache License, Version 2.0 (the "License"); <br>
* you may not use this file except in compliance with the License.<br>
* You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing,<br>
* software distributed under the License is distributed on an "AS IS" BASIS, <br>
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
* See the License for the specific language governing permissions and <br>
* limitations under the License.
* <p>
* Copyright (c) since 2004 at Multimedia- & E-Learning Services (MELS),<br>
* University of Zurich, Switzerland.
* <p>
*/

package org.olat.modules.cp;

import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.olat.core.gui.components.tree.GenericTreeModel;
import org.olat.core.gui.components.tree.GenericTreeNode;
import org.olat.core.gui.components.tree.TreeNode;
import org.olat.core.logging.AssertException;
import org.olat.core.logging.OLATRuntimeException;
import org.olat.core.util.Formatter;
import org.olat.core.util.vfs.VFSLeaf;
import org.olat.core.util.xml.XMLParser;
import org.olat.ims.resources.IMSEntityResolver;

/**
*  Description:<br>
* @author Felix Jost
*/
public class CPManifestTreeModel extends GenericTreeModel {

  private Element rootElement;
  private Map  nsuris = new HashMap(2);
  private Map hrefToTreeNode = new HashMap();
  private Map resources; // keys: resource att 'identifier'; values: resource att 'href'

  /**
   * Constructor of the content packaging tree model
   * @param manifest the imsmanifest.xml file
   */
  CPManifestTreeModel(VFSLeaf manifest) {
    Document doc = loadDocument(manifest);
    // get all organization elements. need to set namespace
    rootElement = doc.getRootElement();
    String nsuri = rootElement.getNamespace().getURI();
    nsuris.put( "ns", nsuri);

    XPath meta = rootElement.createXPath("//ns:organization");
    meta.setNamespaceURIs(nsuris);
    Element orgaEl = (Element) meta.selectSingleNode(rootElement); // TODO: accept several organizations?
    if (orgaEl == null) throw new AssertException("could not find element organization");

    XPath metares = rootElement.createXPath("//ns:resources");
    metares.setNamespaceURIs(nsuris);
    Element elResources = (Element) metares.selectSingleNode(rootElement);
    if (elResources == null) throw new AssertException("could not find element resources");
   
    List resourcesList = elResources.elements("resource");
    resources = new HashMap(resourcesList.size());
    for (Iterator iter = resourcesList.iterator(); iter.hasNext();) {
      Element elRes = (Element) iter.next();
      String identVal = elRes.attributeValue("identifier");
      String hrefVal = elRes.attributeValue("href");
      if (hrefVal != null) { // href is optional element for resource element
        try {
          hrefVal = URLDecoder.decode(hrefVal, "UTF-8");
        } catch (UnsupportedEncodingException e) {
          // each JVM must implement UTF-8
        }
      }
      resources.put(identVal, hrefVal);
    }
    GenericTreeNode gtn = buildNode(orgaEl);
    setRootNode(gtn);
    rootElement = null; // help gc
    resources = null;
  }
 
  /**
   * @param href
   * @return TreeNode representing this href
   */
  public TreeNode lookupTreeNodeByHref(String href) {
    return (TreeNode) hrefToTreeNode.get(href);
  }

  private GenericTreeNode buildNode(Element item) {
    GenericTreeNode gtn = new GenericTreeNode();

    // extract title
    String title = item.elementText("title");
    if (title == null) title = item.attributeValue("identifier");
    gtn.setAltText(title);
    gtn.setTitle(title);
   
    if (item.getName().equals("organization")) {
      gtn.setIconCssClass("o_cp_org");
      gtn.setAccessible(false);
    } else if (item.getName().equals("item")) {
      gtn.setIconCssClass("o_cp_item");
      //set resolved file path directly
      String identifierref = item.attributeValue("identifierref");
      XPath meta = rootElement.createXPath("//ns:resource[@identifier='" + identifierref + "']");
      meta.setNamespaceURIs(nsuris);
      String href = (String) resources.get(identifierref);
      if (href != null) {
        gtn.setUserObject(href);
        // allow lookup of a treenode given a href so we can quickly adjust the menu if the user clicks on hyperlinks within the text
        hrefToTreeNode.put(href, gtn);
      }
      else gtn.setAccessible(false);
    }
   
    List chds = item.elements("item");
    int childcnt = chds.size();
    for (int i = 0; i < childcnt; i++) {
      Element childitem = (Element) chds.get(i);
      GenericTreeNode gtnchild = buildNode(childitem);
      gtn.addChild(gtnchild);
    }
    return gtn;
  }
 
  private Document loadDocument(VFSLeaf documentF) {
    InputStream in = null;
    Document doc = null;
    try {
      in = documentF.getInputStream();
      XMLParser xmlParser = new XMLParser(new IMSEntityResolver());
      doc = xmlParser.parse(in, false);
      in.close();
    }
    catch (IOException e) {
      throw new OLATRuntimeException(CPManifestTreeModel.class, "could not read and parse from file " + documentF, e);
    }
    finally {
      try {
        if (in != null)
          in.close();
      }
      catch (Exception e) {
        // we did our best to close the inputStream
      }
    }
    return doc;
  }

}
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