upnpdevicefactory.java

国外的j2me播放器软件

package no.auc.one.portableplayer.communication;

import java.io.*;
import java.util.*;

import javax.microedition.io.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.apache.log4j.*;

public abstract class UPnPDeviceFactory {
	private static Logger LOG = Logger.getLogger("DevFac");
    private UPnPDiscovery discoDevices = new UPnPDiscovery();
	
    public void cancel() throws IOException {
        discoDevices.cancel();
    }
	
    /**
     * Searches for devices using UPnPDiscovery and retrieves description for 
     * the devices found.
     * 
     * This method swaps the content of the Vector returned by UPnPDiscovery 
     * with a UPnPDevice.
     *  
     * @param searchString String to be searched for.
     * @param deviceHandler Handler for this kind of search string. I.e. it 
     *                      should be able to handle the devices expected to 
     *                      be found by this search.
     * @return Devices found.
     */
    protected Vector findUPnPDevice(
		String searchString, 
		UPnPDeviceDescriptionHandler deviceHandler) 
	{
		Vector devList = null;
		
        Vector locationUrls = discoDevices.start(
            searchString,
			5); // max duration set to 5 seconds
			
        if (locationUrls == null || locationUrls.size() <= 0) {
            LOG.debug("No devices discovered.");
            return null;
        }
		
        devList = locationUrls;
        
	    for(int i = 0; i < locationUrls.size(); i++) {
            Object o = locationUrls.elementAt(i);
            if (o == null || !(o instanceof String)) {
                locationUrls.removeElementAt(i--);
                continue;
            }
            
            String url = (String)o;
            UPnPDevice dev = getUPnPDevice(url, deviceHandler);
            if (dev == null) {
                locationUrls.removeElementAt(i--);
            } else {
                devList.setElementAt(dev, i);
            }
	    }
        
		return devList;
    }
    
    public UPnPDevice getUPnPDevice(
		String locationUrl, 
		UPnPDeviceDescriptionHandler deviceHandler) 
	{
		UPnPDevice dev = null;
        HttpConnection conn = null;
		
        try{								
    	    conn = (HttpConnection)Connector.open(locationUrl);
    	    conn.setRequestMethod(HttpConnection.GET);
    	    conn.setRequestProperty("Content-Length","0");				
    				   
            SAXParserFactory pfactory = SAXParserFactory.newInstance();
            SAXParser parser = pfactory.newSAXParser();
			
			deviceHandler.setLocationUrl(locationUrl);
			
            InputStream is = conn.openInputStream();
            if (is != null) {
                parser.parse(is, deviceHandler);
                dev = deviceHandler.getDevice();

                // Output the elements of this device :)
                LOG.debug(
                    "Device found found " + 
                    " Name:" + dev.friendlyName + 
                    " URLBase:"  + dev.urlBase);                
            }          
         } catch (ParserConfigurationException pce) {
             LOG.debug("PCE exception in getUPnPDevice" + pce.toString());
             pce.printStackTrace();
         } catch (SAXException se) {
             LOG.debug("SAXExceptio in getUPnPDevice" + se.toString());
             se.printStackTrace();
         } catch (ConnectionNotFoundException cnfe) { 
             LOG.debug("Connection not found. " + cnfe.toString());
             cnfe.printStackTrace();
    	 } catch (IOException ioe) {
             LOG.debug("Error while getting device description. " + ioe.toString());
             ioe.printStackTrace();
        } catch (NullPointerException npe){
            System.out.println("Nullpointerexception: " + npe);
            npe.printStackTrace();            
         } finally {
             if (conn != null) {
                 try {
                    conn.close();
                } catch (Exception e) {
                    // Don't care. Do nothing                    
                }
             }
             
             System.err.println("Finished getUPnPDevice");
         }
		         
		 return dev;
    }
}