constructdomtree.java

使用spring构建一个简单的工作流引擎

package org.iocworkflow.test.sequence.ratedrop;



import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.dom.DOMSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.iocworkflow.BaseActivity;
import org.iocworkflow.ProcessContext;
import org.w3c.dom.Document;
import org.w3c.dom.Element;


/**
 * Class:ConstructDOMTreeActivity
 * Creation Date: Mar 12, 2005
 * CVS ID $Id:$
 * 
 * Build a DOM tree based on Airline Route and Price Drop data
 * 
 *  @author sdodge
 *  @since $Date:$
 */
public class ConstructDOMTree extends BaseActivity {
    
    private Log log = LogFactory.getLog(ConstructDOMTree.class);

    /* (non-Javadoc)
     * @see org.iocworkflow.Activity#execute(org.iocworkflow.ProcessContext)
     */
    public ProcessContext execute(ProcessContext context) throws Exception {
        
        RateDropContext rateDropCtx = (RateDropContext)context;
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(false);
        factory.setValidating(false);
        
        DocumentBuilder builder = null;
        try {
            builder = factory.newDocumentBuilder();
        }catch (ParserConfigurationException pe) {
            log.fatal("Error Building DOM tree Parser configurtion error, Factory could not retrieve new builder instance!", pe);
            rateDropCtx.setStopEntireProcess(true);
            return context;
        }
        Document xmlDoc = builder.newDocument();
        Element rate_drop = xmlDoc.createElement("rate-drop");
        rate_drop.setAttribute("dropAmount", rateDropCtx.getSeedData().getRateDrop().toString());
        xmlDoc.appendChild(rate_drop);
        
        Element airline = xmlDoc.createElement("airline");
        airline.setAttribute("airlineId", rateDropCtx.getSeedData().getAirlineId().toString());
        airline.setAttribute("name", rateDropCtx.getSeedData().getAirlineName());
        rate_drop.appendChild(airline);
        
        Element route = xmlDoc.createElement("route");
        route.setAttribute("routeId", rateDropCtx.getSeedData().getRouteId().toString());
        route.setAttribute("origin", rateDropCtx.getSeedData().getRouteOrigin());
        route.setAttribute("destination", rateDropCtx.getSeedData().getRouteDestination());
        rate_drop.appendChild(route);
        
        
        log.debug("++++++++Resulting DOM tree+++++++:"+getPrettyXml(xmlDoc));

        
        
        rateDropCtx.setMessageDom(new DOMSource(xmlDoc));
  
        
        
        return context;
    }

    /**
     * @param rate_drop
     * @return
     */
    private String getPrettyXml( Document rateDOM) {
        String result = rateDOM.toString();
        Writer writer = new StringWriter();
        
        OutputFormat fmt = new OutputFormat(rateDOM, "UTF-8", true);
        XMLSerializer serializer = new XMLSerializer(writer, fmt);
        try {
            writer.write("\n");
            serializer.serialize(rateDOM);
            result = ((StringWriter)writer).getBuffer().toString();
        } catch (IOException e) {
            
        }
        return result;
    }

}