birt barcode plugin MORE COMPLEX EXAMPLES in Font

Printer Data Matrix ECC200 in Font MORE COMPLEX EXAMPLES

import net.jini.discovery.DiscoveryListener; import net.jini.discovery.DiscoveryEvent; import net.jini.core.lookup.ServiceRegistrar; import net.jini.core.lookup.ServiceTemplate; import net.jini.lookup.entry.Location; import net.jini.core.lookup.ServiceItem; import net.jini.core.lookup.ServiceMatches; import net.jini.core.entry.Entry; /** * TestPrinterDistance.java */ public class TestPrinterDistance implements DiscoveryListener { protected Distance distance = null; protected Object distanceLock = new Object(); protected Vector printers = new Vector(); public static void main(String argv[]) { new TestPrinterDistance(); // stay around long enough to receive replies try { Thread.currentThread().sleep(10000L); } catch(java.lang.InterruptedException e) { // do nothing } } public TestPrinterDistance() { System.setSecurityManager(new RMISecurityManager()); LookupDiscovery discover = null; try { discover = new LookupDiscovery(LookupDiscovery.ALL_GROUPS); } catch(Exception e) { System.err.println(e.toString()); System.exit(1); } discover.addDiscoveryListener(this); } public void discovered(DiscoveryEvent evt) { ServiceRegistrar[] registrars = evt.getRegistrars(); for (int n = 0; n < registrars.length; n++) { System.out.println("Service found"); ServiceRegistrar registrar = registrars[n]; new LookupThread(registrar).start(); } } public void discarded(DiscoveryEvent evt) {

// empty } class LookupThread extends Thread { ServiceRegistrar registrar; LookupThread(ServiceRegistrar registrar) { this.registrar = registrar; } public void run() { synchronized(distanceLock) { // only look for one distance service if (distance == null) { lookupDistance(); } if (distance != null) { // found a new distance service // process any previously found printers synchronized(printers) { for (int n = 0; n < printers.size(); n++) { ServiceItem item = (ServiceItem) printers.elementAt(n); reportDistance(item); } } } } ServiceMatches matches = lookupPrinters(); for (int n = 0; n < matches.items.length; n++) { if (matches.items[n] != null) { synchronized(distanceLock) { if (distance != null) { reportDistance(matches.items[n]); } else { synchronized(printers) { printers.addElement(matches.items[n]); } } } } } } /* * We must be protected by the lock on distanceLock here */ void lookupDistance() { // If we don't have a distance service, see if this // locator knows of one Class[] classes = new Class[] {Distance.class};

ServiceTemplate template = new ServiceTemplate(null, classes, null); try { distance = (Distance) registrar.lookup(template); } catch(java.rmi.RemoteException e) { e.printStackTrace(); } } ServiceMatches lookupPrinters() { // look for printers with // wildcard matching on all fields of Location Entry[] entries = new Entry[] {new Location(null, null, null)}; Class[] classes = new Class[1]; try { classes[0] = Class.forName("common.Printer"); } catch(ClassNotFoundException e) { System.err.println("Class not found"); System.exit(1); } ServiceTemplate template = new ServiceTemplate(null, classes, entries); ServiceMatches matches = null; try { matches = registrar.lookup(template, 10); } catch(java.rmi.RemoteException e) { e.printStackTrace(); } return matches; } /** * report on the distance of the printer from * this client */ void reportDistance(ServiceItem item) { Location whereAmI = getMyLocation(); Location whereIsPrinter = getPrinterLocation(item); if (whereIsPrinter != null) { int dist = distance.getDistance(whereAmI, whereIsPrinter); System.out.println("Found a printer at " + dist + " units of length away"); } } Location getMyLocation() { return new Location("1", "1", "Building 1"); } Location getPrinterLocation(ServiceItem item) {

Entry[] entries = item.attributeSets; for (int n = 0; n < entries.length; n++) { if (entries[n] instanceof Location) { return (Location) entries[n]; } } return null; } } } // TestPrinterDistance A number of services will need to be running. At least one distance service will be needed, implementing the interface Distance: package common; import net.jini.lookup.entry.Location; /** * Distance.java */ public interface Distance extends java.io.Serializable { int getDistance(Location loc1, Location loc2); } // Distance The following is an example implementation of a distance service: package complex; import net.jini.lookup.entry.Location; /** * DistanceImpl.java */ public class DistanceImpl implements common.Distance { public DistanceImpl() { } /** * A very naive distance metric */ public int getDistance(Location loc1, Location loc2) { int room1, room2; try { room1 = Integer.parseInt(loc1.room); room2 = Integer.parseInt(loc2.room); } catch(Exception e) { return -1; } int value = room1 - room2;

return (value > 0 value : -value); } } // DistanceImpl Earlier in this chapter I provided the code for PrinterImpl. A simple program to start up a distance service and two printers is as follows: package complex; import printer.Printer30; import printer.Printer20; import complex.DistanceImpl; import net.jini.lookup.JoinManager; import net.jini.core.lookup.ServiceID; import net.jini.lookup.ServiceIDListener; import net.jini.lease.LeaseRenewalManager; import net.jini.discovery.LookupDiscovery; import net.jini.lookup.entry.Location; import net.jini.core.entry.Entry; import net.jini.discovery.LookupDiscoveryManager; import java.rmi.RMISecurityManager; /** * PrinterServerLocation.java */ public class PrinterServerLocation implements ServiceIDListener { public static void main(String argv[]) { new PrinterServerLocation(); // run forever Object keepAlive = new Object(); synchronized(keepAlive) { try { keepAlive.wait(); } catch(InterruptedException e) { // do nothing } } } public PrinterServerLocation() { System.setSecurityManager(new RMISecurityManager()); JoinManager joinMgr = null; try { LookupDiscoveryManager mgr = new LookupDiscoveryManager(LookupDiscovery.ALL_GROUPS, null /* unicast locators */, null /* DiscoveryListener */); // distance service joinMgr = new JoinManager(new DistanceImpl(), null,