org.mycore.common.xml.MCRDynamicURIResolver 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
* Extend this class to include dynamic jdom content. The content is loaded
* from a xml file, which have to be set by the setXmlFile
* method.
*
* The dynamic comes into play by the variables that can be defined for the
* uri. In general they are set directly behind the uri prefix. For example:
*
*
* uriprefix:value1:value2:value3... or
* uriprefix:varname1=varvalue1:varname2=varvalue2:varname3=varname3...
*
* In the xml file you can use these variables with curly brackets '{}'.
* For more informations about the syntax see
* MCRTextResolver. Heres only a short example
* what is possible:
* myURIResolver:classId=class_000_1:levels=-1:axis=children
*
* <dynIncl>
* <panel>
* <hidden var="@classid" default="{classId}"/>
* <include uri="dynClassification:editor:{levels}:{axis}:{classId}[:{categId}]"/>
* <panel/>
* </dynIncl>
*
*
* @see MCRTextResolver
* @author Matthias Eichner
*/
public abstract class MCRDynamicURIResolver implements URIResolver {
private static final Logger LOGGER = LogManager.getLogger(MCRDynamicURIResolver.class);
protected Element cachedElement;
protected File xmlFile;
protected long lastModified;
public MCRDynamicURIResolver() {
lastModified = 0;
cachedElement = null;
xmlFile = null;
}
/**
* Sets the xml file. From this file the jdom content
* will be created.
*
* @param xmlFile xml file object
*/
public void setXmlFile(File xmlFile) {
this.xmlFile = xmlFile;
if (!xmlFile.exists()) {
LOGGER.error(new FileNotFoundException());
}
}
public Element resolveElement(String uri) throws Exception {
if (xmlFile == null) {
throw new NullPointerException("No xml file set in '" + this.getClass().getName() + "'!");
}
Element rootElement = getRootElement();
Hashtable variablesMap = createVariablesMap(uri);
resolveVariablesFromElement(rootElement, variablesMap);
return rootElement;
}
protected Element getRootElement() {
if (cachedElement == null || xmlFile.lastModified() > lastModified) {
try {
SAXBuilder builder = new SAXBuilder();
Document doc = builder.build(xmlFile);
cachedElement = doc.getRootElement();
lastModified = System.currentTimeMillis();
} catch (Exception exc) {
LOGGER.error("Error while parsing {}!", xmlFile, exc);
return null;
}
}
// clone it for further replacements
// TODO: whats faster? cloning or building it new from file
return cachedElement.clone();
}
/**
* This method creates a hashtable that contains variables. There are two
* possibilities for getting the name of a variable from the uri:
*
* - uriprefix:value1:value2:value3
* - uriprefix:varname1=varvalue1:varname2=varvalue2:varname3=varname3
*
* Both options can be mixed, but this is not recommended.
* For the first option the name of the variables is 'x', where 'x' is a number
* for the position in the uri. To get the first value use {1}, to get the second
* one use {2} and so on.
*
* @param uri the whole uri
* @return a hashtable with all variables from the uri
*/
protected Hashtable createVariablesMap(String uri) {
Hashtable variablesMap = new Hashtable<>();
String uriValue = uri.substring(uri.indexOf(':') + 1);
String[] variablesArr = uriValue.split(":");
for (int i = 0; i < variablesArr.length; i++) {
int equalsSignIndex = variablesArr[i].indexOf("=");
if (equalsSignIndex == -1) {
String varName = String.valueOf(i + 1);
String varValue = variablesArr[i];
variablesMap.put(varName, varValue);
} else {
String varName = variablesArr[i].substring(0, equalsSignIndex);
String varValue = variablesArr[i].substring(equalsSignIndex + 1);
variablesMap.put(varName, varValue);
}
}
return variablesMap;
}
/**
* This method runs through the whole content of the startElement and
* tries to resolve all variables in texts and attributes.
*
* @param startElement where to start to resolve the variables
* @param variablesMap a map of all variables
*/
protected void resolveVariablesFromElement(Element startElement, Hashtable variablesMap) {
Iterator it = startElement.getDescendants(Filters.element());
MCRTextResolver varResolver = new MCRTextResolver(variablesMap);
while (it.hasNext()) {
Element element = it.next();
// text
String text = element.getText();
if (text != null && !text.equals("") && text.contains("{")) {
element.setText(varResolver.resolve(text));
}
// attributes
for (Attribute attrib : element.getAttributes()) {
String attribValue = attrib.getValue();
if (attribValue.contains("{")) {
attrib.setValue(varResolver.resolve(attribValue));
}
}
}
}
}