org.mycore.frontend.servlets.MCRDerivateLinkServlet Maven / Gradle / Ivy
/*
* This file is part of *** M y C o R e ***
* See http://www.mycore.de/ for details.
*
* MyCoRe is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* MyCoRe is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MyCoRe. If not, see .
*/
package org.mycore.frontend.servlets;
import java.util.Collection;
import java.util.Map;
import org.jdom2.Element;
import org.mycore.common.content.MCRJDOMContent;
import org.mycore.datamodel.common.MCRLinkTableManager;
import org.mycore.datamodel.metadata.MCRMetadataManager;
import org.mycore.datamodel.metadata.MCRObject;
import org.mycore.datamodel.metadata.MCRObjectID;
import org.mycore.frontend.MCRFrontendUtil;
/**
* This servlet is used to display all parents of an mycore object and their
* containing derivates. It returns a xml document which will be transformed
* by derivateLinks-parentList.xsl.
*
* @author Matthias Eichner
*/
public class MCRDerivateLinkServlet extends MCRServlet {
private static final long serialVersionUID = 1L;
protected static String derivateLinkErrorPage = "error_derivatelink.xml";
@Override
protected void doGetPost(MCRServletJob job) throws Exception {
@SuppressWarnings("unchecked")
Map pMap = job.getRequest().getParameterMap();
String webpage = pMap.get("subselect.webpage")[0];
String mcrId = getSubParameterValueOfBrowserAddressParameter(webpage, "mcrid");
String parentId = getSubParameterValueOfBrowserAddressParameter(webpage, "parentID");
// create a new root element
Element rootElement = new Element("derivateLinks-parentList");
MCRObjectID objId = MCRObjectID.getInstance(mcrId);
if (MCRMetadataManager.exists(objId)) {
/* mcr object exists in datastore -> add all parent with their
* derivates to the jdom tree */
addParentsToElement(rootElement, objId);
} else if (parentId != null && MCRMetadataManager.exists(MCRObjectID.getInstance(parentId))) {
/* mcr object doesnt exists in datastore -> use the parent id
* to create the content */
Element firstParent = getMyCoReObjectElement(MCRObjectID.getInstance(parentId));
if (firstParent != null) {
rootElement.addContent(firstParent);
}
addParentsToElement(rootElement, MCRObjectID.getInstance(parentId));
}
// check if root element has content -> if not, show an error page
if (rootElement.getContentSize() == 0) {
job.getResponse().sendRedirect(
job.getResponse().encodeRedirectURL(MCRFrontendUtil.getBaseURL() + derivateLinkErrorPage));
return;
}
// set some important attributes to the root element
rootElement.setAttribute("session", pMap.get("subselect.session")[0]);
rootElement.setAttribute("varpath", pMap.get("subselect.varpath")[0]);
rootElement.setAttribute("webpage", webpage);
// transform & display the generated xml document
getLayoutService().doLayout(job.getRequest(), job.getResponse(), new MCRJDOMContent(rootElement));
}
/**
* This method adds all parents and their derivates
* iterative to the given element.
*
* @param toElement the element where the parents and derivates will be added
* @param objId the source object id
*/
private void addParentsToElement(Element toElement, MCRObjectID objId) {
MCRObjectID pId = objId;
while ((pId = getParentId(pId)) != null) {
Element parentElement = getMyCoReObjectElement(pId);
if (parentElement != null) {
toElement.addContent(parentElement);
}
}
}
/**
* Returns the parent object id of an mcr object.
*
* @param objectId from which id
* @return the parent id
*/
private MCRObjectID getParentId(MCRObjectID objectId) {
MCRObject obj = MCRMetadataManager.retrieveMCRObject(objectId);
return obj.getStructure().getParentID();
}
/**
* Creates a new mcrobject jdom element which contains all
* derivates with their ids as children.
*
* @param objectId id of the mcr object
* @return a new jdom element
*/
private Element getMyCoReObjectElement(MCRObjectID objectId) {
Collection derivates = MCRLinkTableManager.instance().getDestinationOf(objectId, "derivate");
if (derivates.size() <= 0) {
return null;
}
Element objElement = new Element("mycoreobject");
objElement.setAttribute("id", objectId.toString());
for (String derivate : derivates) {
Element derElement = new Element("derivate");
derElement.setAttribute("id", derivate);
objElement.addContent(derElement);
}
return objElement;
}
/**
* Returns the value of a parameter which is embedded in a parameter
* of the browser address.
*
* @param browserAddressParameter the separated parameter from the browser address
* @param subParameter the sub parameter to search
* @return the value of the sub parameter
*/
private String getSubParameterValueOfBrowserAddressParameter(String browserAddressParameter, String subParameter) {
String value = null;
int index = browserAddressParameter.indexOf(subParameter);
if (index != -1) {
int startIndex = index + subParameter.length() + 1;
int endIndex = browserAddressParameter.indexOf("&", index + 1);
if (endIndex == -1) {
endIndex = browserAddressParameter.length();
}
value = browserAddressParameter.substring(startIndex, endIndex);
}
return value;
}
}