source: trunk/docx4j/src/main/java/org/docx4j/utils/XPathAwareCloner.java @ 1752

package org.docx4j.utils;

import java.util.List;

import javax.xml.bind.Binder;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.namespace.QName;

import org.apache.log4j.Logger;
import org.docx4j.XmlUtils;
import org.docx4j.jaxb.Context;
import org.docx4j.jaxb.JaxbValidationEventHandler;
import org.docx4j.wml.P;
import org.w3c.dom.Node;

/**
 * Some users wish to be able to use an XPath on the result
 * of cloning a JAXB object.  This variant on XmlUtils.deepCopy 
 * allows that.
 * 
 * Note that if you use this object's deepCopy method more 
 * than once, the results returned by getJAXBNodesViaXPath
 * will only be on your last deepCopy.
 */
public class XPathAwareCloner {
        
        private static Logger log = Logger.getLogger(XPathAwareCloner.class);   
                        
        /** Clone this JAXB object, using default JAXBContext. */ 
        public Object deepCopy(Object o) {              
                return deepCopy(o, Context.jc);         
        }       
        
        Object jaxbElement;
        
        /** Clone this JAXB object
         * @param value
         * @param jc
         * @return
         */
        public Object deepCopy(Object o, JAXBContext jc) {
                
                if (o==null) {
                        throw new IllegalArgumentException("Can't clone a null argument");
                }
                
                try {
                        // To be XPath aware, we need a binder.
                        // But to unmarshall using a binder, we need to unmarshal a node.
                        // So, our marshall should be to a W3C document
                        org.w3c.dom.Document doc = XmlUtils.marshaltoW3CDomDocument(o, jc);
                        
                        // OK, unmarshall to binder
                        binder = jc.createBinder();
                        JaxbValidationEventHandler eventHandler = new JaxbValidationEventHandler();
                        eventHandler.setContinue(false);
                        binder.setEventHandler(eventHandler);
                        jaxbElement =  binder.unmarshal( doc);
                        
                        //log.debug("Clone: " + XmlUtils.marshaltoString(jaxbElement, true, true));
                        
                        return jaxbElement;
                } catch (JAXBException ex) {
                        throw new IllegalArgumentException(ex);
                }
        }
        

        private Binder<Node> binder;
        
        
        /**
         * Enables synchronization between XML infoset nodes and JAXB objects 
         * representing same XML document.
         * 
         * An instance of this class maintains the association between XML nodes
         * of an infoset preserving view and a JAXB representation of an XML document. 
         * Navigation between the two views is provided by the methods 
         * getXMLNode(Object) and getJAXBNode(Object) .
         * 
         * In theory, modifications can be made to either the infoset preserving view or 
         * the JAXB representation of the document while the other view remains
         * unmodified. The binder ought to be able to synchronize the changes made in
         * the modified view back into the other view using the appropriate
         * Binder update methods, #updateXML(Object, Object) or #updateJAXB(Object).
         * 
         * But JAXB doesn't currently work as advertised .. access to this
         * object is offered for advanced users on an experimental basis only.
         */
        public Binder<Node> getBinder() {
                
                return binder;
        }
        
        /**
         * Fetch JAXB Nodes matching an XPath (for example "//w:p").
         * 
         * If you have modified your JAXB objects (eg added or changed a 
         * w:p paragraph), you need to update the association. The problem
         * is that this can only be done ONCE, owing to a bug in JAXB:
         * see https://jaxb.dev.java.net/issues/show_bug.cgi?id=459
         * 
         * So this is left for you to choose to do via the refreshXmlFirst parameter.   
         * 
         * @param xpathExpr
         * @param refreshXmlFirst
         * @return
         * @throws JAXBException
         */     
        public List<Object> getJAXBNodesViaXPath(String xpathExpr, boolean refreshXmlFirst) 
                        throws JAXBException {
                
                return XmlUtils.getJAXBNodesViaXPath(binder, jaxbElement, xpathExpr, refreshXmlFirst);
        }       
        
        /**
         * @param args
         * @throws JAXBException 
         */
        public static void main(String[] args) throws JAXBException {
                
            String pString = "<w:p xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\">"
                      +"<w:r>"
                        +"<w:t xml:space=\"preserve\">Here is some text.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:rPr>"
                          +"<w:i/>"
                        +"</w:rPr>"
                        +"<w:t>An italic run.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:rPr>"
                          +"<w:i/>"
                        +"</w:rPr>"
                        +"<w:t xml:space=\"preserve\">"  +"</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t>More stuff.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t xml:space=\"preserve\">"  +"</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:rPr>"
                          +"<w:b/>"
                        +"</w:rPr>"
                        +"<w:t>More stuff.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t xml:space=\"preserve\">" +"</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t xml:space=\"preserve\">The run we are seeking.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:rPr>"
                          +"<w:b/>"
                        +"</w:rPr>"
                        +"<w:t>More stuff.</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t xml:space=\"preserve\">" +"</w:t>"
                      +"</w:r>"
                      +"<w:r>"
                        +"<w:t>More stuff.</w:t>"
                      +"</w:r>"
                    +"</w:p>";
            
            P pIn = (P)XmlUtils.unmarshalString(pString);
            
            XPathAwareCloner cloner = new XPathAwareCloner();
            P clonedP = (P)cloner.deepCopy(pIn);
            
            List<Object> results = cloner.getJAXBNodesViaXPath("//w:r[contains( w:t, 'seeking')]", false);
            //List<Object> results = cloner.getJAXBNodesViaXPath("//w:r", false);
            
            int i=1;
            for (Object result: results) {
                System.out.println("\n\r" + i + ": " + XmlUtils.marshaltoString(result, true, true));
                i++;
            }
                

        }

}