| Methods Summary |
|---|
| private void | connectToRestoPeers()
// Enumerate all the RestoPeer pipe advertisments we have discovered
// and attempt to connect a pipe which each of them
for (Enumeration en = restoPeerAdvs.elements();
en.hasMoreElements();) {
PipeAdvertisement padv = (PipeAdvertisement) en.nextElement();
try {
System.out.println(
"Attempting to connect to discovered RestoPeer");
// Create an output pipe connection to the RestoPeer
OutputPipe pipeOut = pipes.createOutputPipe(padv,
rtimeout);
// Check if we have a connected pipe
if (pipeOut == null) {
// Failed; go to next RestoPeer
System.out.println(
"Failure to connect to RestoPeer Pipe:" +
padv.getName());
continue;
}
// Save the output pipe
restoPeerPipes.addElement(pipeOut);
System.out.println("Connected pipe to " + padv.getName());
} catch (Exception e) {
// Error during connection go to next RestoPeer
System.out.println("RestoPeer may not be there anymore:" +
padv.getName());
continue;
}
}
|
| private void | discoverRestoServices()
int found = 0; // Count of RestoPeers found
int count = 10; // Discovery retries
ModuleSpecAdvertisement restoSrv; // RestoPeer Service Advertisement
System.out.println("Locating RestoPeers in the RestoNet Peergroup");
// Try to find at least two RestoPeers (an arbitrary number).
while (count-- >0) {
try {
// Check if we already have restaurant advertisements
// in our local peer cache
Enumeration ae =
disco.getLocalAdvertisements(DiscoveryService.ADV, "Name",
"JXTASPEC:RestoNet:Service:*");
// If we found some advertisements in the cache,
// add them to the list
if (ae != null && ae.hasMoreElements()) {
// Reset count and RestoPeerAdvs as we have
// just retrieved all advertisements, including
// previously cached ones
found = 0;
restoPeerAdvs.removeAllElements();
while (ae.hasMoreElements()) {
restoSrv = (ModuleSpecAdvertisement) ae.nextElement();
// Extract the pipe advertisement from the
// service module spec adv. The pipe advertisement
// is used to connect to the service; it is
// part of the Param section of the advertisement
restoPeerAdvs.addElement(restoSrv.getPipeAdvertisement());
++found;
}
if (found > 1)
break; // Want to find at least two
}
// Did not find enough advertisement in the cache.
// Send a remote discovery request to search for more
// RestoPeer service advertisements
disco.getRemoteAdvertisements(null,
DiscoveryService.ADV,
"Name", "JXTASPEC:RestoNet:Service:*", 5, null);
// Give the peers a chance to respond
try {
Thread.sleep(timeout);
} catch (InterruptedException e) {}
} catch (IOException e){
// Found nothing! Move on
}
}
// Completed RestoPeer Discovery
System.out.println("Found " + found + " RestoPeer Service(s)");
|
| private boolean | joinRestoNet()
int count = 3; // maximum number of attempts to discover
System.out.println("Attempting to discover the RestoNet Peergroup");
// Get the Discovery service handle from the NetPeerGroup
DiscoveryService hdisco = netpg.getDiscoveryService();
// All discovered RestoNet Peers
Enumeration ae = null;
// Loop until we find the "RestoNet" Peergroup advertisement
// or we've exhausted the desired number of attempts
while (count-- > 0) {
try {
// Check if we have the advertisement in the local
// peer cache
ae = hdisco.getLocalAdvertisements(DiscoveryService.GROUP,
"Name", "RestoNet");
// If we found the RestoNet advertisement, we are done
if ((ae != null) && ae.hasMoreElements())
break;
// The RestoNet advertisement is not in the local
// cache . Send a discovery request to search for it.
hdisco.getRemoteAdvertisements(null,
DiscoveryService.GROUP, "Name", "RestoNet", 1, null);
// Wait to give peers a chance to respond
try {
Thread.sleep(timeout);
} catch (InterruptedException ie) {}
} catch (IOException e) {
// Found nothing! Move on.
}
}
// Check if we found the RestoNet advertisement
if (ae == null || !ae.hasMoreElements()) {
return false;
}
System.out.println("Found the RestoNet PeerGroup Advertisement");
// Get the advertisement
PeerGroupAdvertisement adv =
(PeerGroupAdvertisement) ae.nextElement();
try {
// Call the PeerGroup Factory to instantiate a new
// peergroup instance
restoNet = netpg.newGroup(adv);
// Get the Discovery and Pipe services to
// be used within the RestoNet Peergroup
disco = restoNet.getDiscoveryService();
pipes = restoNet.getPipeService();
} catch (Exception e) {
System.out.println("Could not create RestoPeerGroup");
return false;
}
System.out.println("The HungryPeer joined the restoNet PeerGroup");
return true;
|
| public static void | main(java.lang.String[] args) // Fries Auction request
HungryPeer myapp = new HungryPeer();
myapp.startJxta();
System.exit(0);
|
| private void | receiveFriesBids()
// Continue until we get all answers
while (true) {
Message msg = null; // Pipe message received
String price = null; // Fries price bid
String brand = null; // RestoPeer name which offers the bid
String specials = null; // Specials offer bid
InputStream ip = null; // Input stream to read message element
StructuredDocument bid = null; //Bid document received
try {
// Wait for a bid message to arrive from a RestoPeer
// Will block until a message arrive
msg = myPipe.waitForMessage();
// Check if the message is valid
if (msg == null) {
if (Thread.interrupted()) {
// We have been asked to stop
System.out.println(
"Abort Receiving bid loop interrupted");
myPipe.close(); // Close the Pipe
return;
}
}
} catch (Exception ex) {
// Error in receiving message
myPipe.close();
System.out.println("Abort Receiving Error receiving bids");
return;
}
// We got a message from a RestoPeer.
// Extract and display infomation about the bid received.
try {
// Extract the Bid document from the message
ip = msg.getElement("Bid").getStream();
bid = StructuredDocumentFactory.newStructuredDocument(
mimeType, ip);
// Parse the document to extract bid information
Enumeration enum = bid.getChildren();
while (enum.hasMoreElements()) {
Element element = (Element) enum.nextElement();
String attr = (String) element.getKey();
String value = (String) element.getValue();
if (attr.equals("Price")) {
price = value;
continue;
}
if (attr.equals("Brand")) {
brand = value;
continue;
}
if (attr.equals("Specials")) {
specials = value;
continue;
}
}
// We got a valid bid. Print it.
System.out.println("Received Fries Bid from RestoPeers (" +
brand + ") at a Price ($" + price +
") \nRestoPeers Special (" + specials + ")");
} catch (Exception e) {
// Broken content
System.out.println("Error extracting bid from the message");
continue;
}
}
|
| private void | sendFriesAuctionRequests()
// Enumerate all the RestoPeer pipe connections we have successfully
// connected to
for (Enumeration en = restoPeerPipes.elements();
en.hasMoreElements();) {
OutputPipe op = (OutputPipe) en.nextElement();
try {
// Construct the request document
StructuredDocument request =
StructuredDocumentFactory.newStructuredDocument(mimeType,
"RestoNet:Request");
// Fill up the Fries auction request argument
Element re;
re = request.createElement("Name", myIdentity);
request.appendChild(re);
re = request.createElement("Fries", friesRequest);
request.appendChild(re);
// Create the pipe message to send
Message msg = pipes.createMessage();
// Fill the first message element which is the HungryPeer
// pipe advertisement return address. We need this
// so RestoPeers can respond to us
msg.addElement(msg.newMessageElement("HungryPeerPipe",
mimeType, myAdv.getDocument(mimeType).getStream()));
// Fill the second message element, which is
// the fries request. Insert the document
// in the message
msg.addElement(msg.newMessageElement("Request",
mimeType, request.getStream()));
// Send the auction message to the RestoPeer
op.send(msg);
System.out.println("Sent Fries Auction Request ("
+ friesRequest + ") to connected peers");
} catch (Exception ex) {
// Error sending auction request
System.out.println(
"Failed to send auction request to RestoPeer");
}
}
|
| private boolean | setHungryPeerPipe()
try {
// Create a pipe advertisement for our hungry peer. This
// pipe will be used within the RestoNet peergroup for other
// peers to talk to our hungry peer
myAdv = (PipeAdvertisement)
AdvertisementFactory.newAdvertisement(
PipeAdvertisement.getAdvertisementType());
// Initialize the advertisement with unique peer information
// So we can communicate
myAdv.setPipeID(IDFactory.newPipeID(restoNet.getPeerGroupID()));
myAdv.setName("restoNet:HungryPipe:" + myIdentity);
// Set the pipe type to be unicast unidrectional
myAdv.setType(PipeService.UnicastType);
// Create the input pipe
myPipe = pipes.createInputPipe(myAdv);
} catch (Exception e) {
System.out.println("Could not create the HungryPeer pipe");
return false;
}
return true;
|
| private void | startJxta()
try {
// Discover (or create) and join the default jxta NetPeerGroup
netpg = PeerGroupFactory.newNetPeerGroup();
} catch (PeerGroupException e) {
//Couldn't initialize; can't continue
System.out.println("Fatal error : creating the NetPeerGroup");
System.exit(1);
}
// Discover and join the RestoNet Peergroup
try {
if (!joinRestoNet()) {
System.out.println("Sorry could not find the RestoNet Peergroup");
System.exit(2);
}
} catch (Exception e) {
System.out.println("Can't join RestoNet group");
System.exit(1);
}
// Set our HungryPeer communication pipe so RestoPeers
// can talk to us
if (!setHungryPeerPipe()) {
System.out.println(
"Aborting due to failure to create our HungryPeer pipe");
System.exit(1);
}
//Attempt to locate RestoPeers in RestoNet
discoverRestoServices();
// Connect to RestoPeers that have been discovered
connectToRestoPeers();
// I am hungry. Send an auction request for French Fries
// to the connected RestoPeers.
sendFriesAuctionRequests();
//Process incoming bids from RestoPeers
receiveFriesBids();
|
