RestoPeerpublic class RestoPeer extends Object
| Fields Summary |
|---|
| private net.jxta.peergroup.PeerGroup | netpg | | private net.jxta.peergroup.PeerGroup | restoNet | | private String | brand | | private String | specials | | private net.jxta.discovery.DiscoveryService | disco | | private net.jxta.pipe.PipeService | pipes | | private net.jxta.protocol.PipeAdvertisement | myAdv | | private net.jxta.pipe.InputPipe | pipeIn | | private int | timeout | | private int | rtimeout | | static String | groupURL |
| Methods Summary |
|---|
| private boolean | createRestoPipe()
int count = 3; // Discovery retry count
Enumeration ae = null; // Discovery response enumeration
try {
System.out.println(
"Attempting to Discover the Restaurant RestoPipe");
// Check if I have already published myself
while (count-- > 0) {
try {
// Check first locally if we have the advertisement cached
ae = disco.getLocalAdvertisements(DiscoveryService.ADV,
"name", "RestoNet:RestoPipe:" + brand);
// If we found our pipe advertisement we are done
if (ae != null && ae.hasMoreElements())
break;
// We did not find the advertisement locally;
// send a remote request
disco.getRemoteAdvertisements(null,
DiscoveryService.ADV, "name",
"RestoNet:RestoPipe:" + brand, 1, null);
// Sleep to allow time for peers to respond to the
// discovery request
try {
Thread.sleep(timeout);
} catch (InterruptedException e) {}
} catch (IOException e) {
// Found nothing! Move on
}
}
if (ae == null || !ae.hasMoreElements()) {
// We did not find the pipe advertisement, so create one
System.out.println(
"Could not find the Restaurant Pipe Advertisement");
// Create a pipe advertisement for our RestoPeer
myAdv = (PipeAdvertisement)
AdvertisementFactory.newAdvertisement(
PipeAdvertisement.getAdvertisementType());
// Assign a unique ID to the pipe
myAdv.setPipeID(
IDFactory.newPipeID(restoNet.getPeerGroupID() ));
// The symbolic name of the pipe is built from
// the brand name of RestoPeer; each RestoPeer
// must therefore have a unique name.
myAdv.setName("RestoNet:RestoPipe:" + brand);
// Set the type of the pipe to be unidirectional
myAdv.setType(PipeService.UnicastType);
// We have the advertisement; publish it
// into our local cache and to the RestoNet PeerGroup.
// We use the default lifetime and the default
// expiration time for remote publishing
disco.publish(myAdv, DiscoveryService.ADV,
PeerGroup.DEFAULT_LIFETIME,
PeerGroup.DEFAULT_EXPIRATION);
disco.remotePublish(myAdv, DiscoveryService.ADV,
PeerGroup.DEFAULT_EXPIRATION);
System.out.println(
"Created the Restaurant Pipe Advertisement");
} else {
// We found an existing pipe advertisement
myAdv = (PipeAdvertisement) ae.nextElement();
System.out.println("Found Restaurant Pipe Advertisement");
}
// Create my input pipe to listen for hungry peers
// requests
pipeIn = pipes.createInputPipe(myAdv);
} catch (Exception e) {
System.out.println("Could not initialize the Restaurant pipe");
return false;
}
return true;
| | private java.lang.String | friesPrice(java.lang.String size)
if (size.equals("small"))
return "$1.50";
if (size.equals("medium"))
return "2.50";
if (size.equals("large"))
return "3.00";
return "error";
| | private void | handleFriesRequest()
InputStream ip = null; // Input Stream to read message
PipeAdvertisement hungryPipe = null; // HungryPeer Requester pipe
StructuredDocument request = null; // Request document
StructuredDocument bid = null; // Response document
// Document mime types
MimeMediaType mimeType = new MimeMediaType("text", "xml");
Element el = null; // Element in document
String name = null; // Name of the sender
String size = null; // Fries size Requested
OutputPipe pipeOut = null; // Output pipe to respond to
// HungryPeer requester
System.out.println("RestoNet Restaurant (" + brand +
") waiting for HungryPeer requests");
// Loop waiting for HungryPeer Requests
while (true) {
Message msg = null; // Incoming pipe message
try {
// Block until a message arrive on the RestoPeer pipe
msg = pipeIn.waitForMessage();
// If message is null discard message
if (msg == null) {
if (Thread.interrupted()) {
// We have been asked to stop
System.out.println("Abort: RestoPeer interrupted");
return;
}
}
// We received a message; extract the request
try {
// Extract the HungryPipe pipe information
// to reply to the sender
ip = msg.getElement("HungryPeerPipe").getStream();
// Construct the associated pipe advertisement
// via the AdvertisementFactory
hungryPipe = (PipeAdvertisement)
AdvertisementFactory.newAdvertisement(mimeType, ip);
// Extract the sender name and fries size requested
// building a StructuredDocument
ip = msg.getElement("Request").getStream();
request = StructuredDocumentFactory.newStructuredDocument
(mimeType, ip);
// Extract the fields from the structured Document
Enumeration enum = request.getChildren();
// Loop over all the elements of the document
while (enum.hasMoreElements()) {
el = (Element) enum.nextElement();
String attr = (String) el.getKey();
String value = (String) el.getValue();
// Extract the HungryPeer Requester Name
if (attr.equals("Name")) {
name = value;
continue;
}
// Extract the Fries size requested
else if (attr.equals("Fries")) {
size = value;
continue;
}
}
} catch (Exception e) {
continue; // Broken content; silently discard
}
System.out.println("Received Request from HungryPeer "
+ name
+ " for "
+ size
+ " Fries.");
// The auction request is valid. We can
// create the output pipe to send the response bid to
// the HungryPeer requester
try {
System.out.println(
"Attempting to create Output Pipe to HungryPeer " +
name);
// Create an output pipe connection to the HungryPeer
pipeOut = pipes.createOutputPipe(hungryPipe,
rtimeout);
// Check if we have a pipe
if (pipeOut == null) {
// Cannot conect the pipe
System.out.println("Could not find HungryPeer pipe");
continue;
}
} catch (Exception e) {
// Pipe creation exception
System.out.println("HungryPeer may not be listening anymore");
continue;
}
// We have a pipe connection to the HungryPeer.
// Now create the Bid Response document
try {
// Construct the Response document
bid = StructuredDocumentFactory.newStructuredDocument(
mimeType,
"RestoNet:Bid");
// Set the Bid values (Brand, price, special)
// in the response document
el = bid.createElement("Brand", brand);
bid.appendChild(el);
el = bid.createElement("Price", friesPrice(size));
bid.appendChild(el);
el = bid.createElement("Specials", specials);
bid.appendChild(el);
// Create a new pipe message
msg = pipes.createMessage();
// Push the Bid offer in the message
msg.addElement(msg.newMessageElement(
"Bid",mimeType, bid.getStream()));
// Send the message
pipeOut.send(msg);
// Close the output pipe connection
pipeOut.close();
} catch (Exception ex) {
System.out.println(
"Error sending bid offer to HungryPeer " + name);
continue;
}
System.out.println("Sent Bid Offer to HungryPeer (" + name +
") Fries price = " + friesPrice(size) +
", special = " + specials);
} catch (Exception e) {
System.out.println("Abort RestoPeer interrupted");
return;
}
}
| | private void | joinRestoNet()
int count = 3; // maximun number of attempts to discover
System.out.println("Attempting to Discover the RestoNet PeerGroup");
// Get the discovery service from the NetPeergroup
DiscoveryService hdisco = netpg.getDiscoveryService();
Enumeration ae = null; // Holds the discovered peers
// Loop until wediscover the RestoNet or
// until we've exhausted the desired number of attempts
while (count-- > 0) {
try {
// search first in the peer local cache to find
// the RestoNet peergroup advertisement
ae = hdisco.getLocalAdvertisements(DiscoveryService.GROUP,
"Name", "RestoNet");
// If we found the RestoNet advertisement we are done
if ((ae != null) && ae.hasMoreElements())
break;
// If we did not find it, we send a discovery request
hdisco.getRemoteAdvertisements(null,
DiscoveryService.GROUP, "Name", "RestoNet", 1, null);
// Sleep to allow time for peers to respond to the
// discovery request
try {
Thread.sleep(timeout);
} catch (InterruptedException ie) {}
} catch (IOException e){
// Found nothing! Move on
}
}
PeerGroupAdvertisement restoNetAdv = null;
// Check if we found the RestoNet advertisement.
// If we didn't, then either
// we are the first peer to join or
// no other RestoNet peers are up.
// In either case, we must create the RestoNet peergroup
if (ae == null || !ae.hasMoreElements()) {
System.out.println(
"Could not find the RestoNet peergroup; creating one");
try {
// Create a new, all-purpose peergroup.
ModuleImplAdvertisement implAdv =
netpg.getAllPurposePeerGroupImplAdvertisement();
restoNet = netpg.newGroup(
mkGroupID(), // Assign new group ID
implAdv, // The implem. adv
"RestoNet", // Name of peergroup
"RestoNet, Inc.");// Description of peergroup
// Get the PeerGroup Advertisement
restoNetAdv = netpg.getPeerGroupAdvertisement();
} catch (Exception e) {
System.out.println("Error in creating RestoNet Peergroup");
throw e;
}
} else {
// The RestoNet advertisement was found in the cache;
// that means we can join the existing RestoNet peergroup
try {
restoNetAdv = (PeerGroupAdvertisement) ae.nextElement();
restoNet = netpg.newGroup(restoNetAdv);
System.out.println(
"Found the RestoNet Peergroup advertisement");
} catch (Exception e) {
System.out.println("Error in creating RestoNet PeerGroup from existing adv");
throw e;
}
}
try {
// Get the discovery and pipe services for the RestoNet Peergroup
disco = restoNet.getDiscoveryService();
pipes = restoNet.getPipeService();
} catch (Exception e) {
System.out.println("Error getting services from RestoNet");
throw e;
}
System.out.println("RestoNet Restaurant (" + brand + ") is on-line");
return;
| | public static void | main(java.lang.String[] args)
RestoPeer myapp = new RestoPeer();
myapp.startJxta();
System.exit(0);
| | private net.jxta.peergroup.PeerGroupID | mkGroupID()
return (PeerGroupID) IDFactory.fromURL(
new URL("urn", "", groupURL));
| | private void | startJxta()
try {
//Discover and join (or start) the default peergroup
netpg = PeerGroupFactory.newNetPeerGroup();
} catch (PeerGroupException e) {
//Couldn't initialize; can't continue
System.out.println("Fatal error : creating the NetPeerGroup");
System.exit(1);
}
// Discover (or create) and join the RestoNet peergroup
try {
joinRestoNet();
} catch (Exception e) {
System.out.println("Can't join or create RestoNet");
System.exit(1);
}
// Discover (or create) and publish a RestoPeer pipe to receive
// auction request for fries from HungryPeers
if (!createRestoPipe()) {
System.out.println("Aborting due to failure to create RestoPeer pipe");
System.exit(1);
}
// Start the RestoPeer server loop to respond to Hungry peers
// fries requests.
handleFriesRequest();
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