edu.nps.moves.examples.MarshallExample Maven / Gradle / Ivy

package edu.nps.moves.examples;

import edu.nps.moves.dis.*;

import java.io.*;
import javax.xml.bind.*;
import java.util.*;

/**
 * Example of using JAXB to marshal and unmarshall PDUs to and from XML. Uses
 * Jaxb 2.1.x.
 * 
 * @author DMcG
 * @version $Id:$
 */
public class MarshallExample {

    /**
     * Shows how to marshal out to XML and read from XML files.
     * @param args
     */
    public static void main(String args[]) {

        // PduContainer is simply a list of PDUs. The PDUs can be of any type;
        // espdu, fire, detonation, etc. The PDU container is an XML root element,
        // meaning that it can be a top level XML document.
        
        PduContainer container = new PduContainer(); // XmlRootElement marked class

        // Create a few PDUs to marshal
        EntityStatePdu espdu = new EntityStatePdu();
        FirePdu firePdu = new FirePdu();
        DetonationPdu detonationPdu = new DetonationPdu();
        FirePdu bang = new FirePdu();

        // Add them to the XmlRootElement container
        container.getPdus().add(espdu);
        container.getPdus().add(firePdu);
        container.getPdus().add(detonationPdu);
        container.getPdus().add(bang);
        
	// Create some more espdus, setting the location, velocity, and entity IDs
	// to be random numbers. This will show that the PDU attributes are actually
        // being marshalled.
        for(int idx = 0; idx < 20; idx++)
        {
            EntityStatePdu pdu = new EntityStatePdu();
            
            Vector3Double loc = pdu.getEntityLocation();
            loc.setX(Math.random());
            loc.setY(Math.random());
            loc.setZ(Math.random());
            
            Vector3Float vel = pdu.getEntityLinearVelocity();
            vel.setX((float)Math.random());
            vel.setY((float)Math.random());
            vel.setZ((float)Math.random());
            
            EntityID eid = pdu.getEntityID();
            eid.setSite((short)(Math.random() * 1000));
            eid.setApplication((short)(Math.random() * 1000));
            eid.setEntity((short)(Math.random() * 1000));
            
            container.getPdus().add(pdu);
        }

        // And marshal it out to an XML file. We have the PduContainer, which 
        // holds all the PDUs. Marshal it out to the given XML file. This uses
        // jaxb; see the javadoc at the JDK 1.6 documents, in the javax.xml.bind
        // package.

        try 
        {
            // The context, which will contain the package of the classes we marshal out
            JAXBContext context = JAXBContext.newInstance("edu.nps.moves.dis"); 
			
            // Choose the file to send to, and make it pretty-print. The marshaller
            // object is responsible for writing the XML, but it needs to be told
            // a few things, such as the file to write to, the format to write it
            // in, and so on. This is part of JAXB;

            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            marshaller.marshal(container, new FileOutputStream("somePdus.xml"));
            

            // Just to prove nothing funny is going on, read the XML file back in
            // from the file we just wrote to. Again, this primarily relies on JAXB,
            // from the javax.xml.bind package for Unmarshaller, JaxbContext, and so on.

            Unmarshaller unmarshaller = context.createUnmarshaller();

            // We get back a PduContainer object from the XML file--this is a container
            // the holds zero or more PDUs.

            PduContainer unmarshalledObject = (PduContainer) unmarshaller.unmarshal(new FileInputStream("somePdus.xml"));
            System.out.println("got " + unmarshalledObject.getNumberOfPdus() + " back");

            // Print out the PDUs; retreive the list of PDUs from the PDU Container
            List unmarshalledPdus = unmarshalledObject.getPdus();
			
            System.out.println("Marshalled PDUs out to XML, read them back, contents of list are...");
            for(int idx = 0; idx < unmarshalledPdus.size(); idx++)
            {
                    Pdu aPdu = unmarshalledPdus.get(idx);
                    System.out.println("   Pdu Type: " + aPdu.getClass().getName());

                    // For the entity state PDUs we put into the PDU container, print out
                    // the contents for the attributes we set
                    if(aPdu instanceof EntityStatePdu)
                    {
                         EntityStatePdu es = (EntityStatePdu)aPdu;
                         System.out.println("      EID:(" + es.getEntityID().getSite() + "," +
                                                                       es.getEntityID().getApplication() + "," +
                                                                       es.getEntityID().getEntity() + ")");
                    }
            }		
        }
        catch (Exception e)
        {
            e.printStackTrace();
            System.out.println(e);
        }
    }
}