Develop Reference

Google GCM XMPP code samples

So, Google used to have a nice page where they gave code sample on how to implement a GCM Xmpp server on this page:
https://developers.google.com/cloud-messaging/ccs
I had bookmarked this answer anytime I wanted to view the implementation
Confused about Google GCM XMPP
But everything linked from in that answer is gone. Google deleted them.
But now, they have removed everything, and added a page that just explains what it does. Sure, but the sample java code would be nice. I tried to go to the sample site on github that they link to
https://github.com/google/gcm
but it only provides samples of HTTP GCM server version.
Can somebody point me to a working code sample please? Or Is there a library out there that would work with c# at all? if not, I would just settle with the java version too.
Thanks.

Here is one I wrote for a class example (with some non-XMPP parts deleted to keep it small enough so I can post the code, but have the full server at http://people.eku.edu/styere/GcmPushServer.java):
// derived from https://developer.android.com/google/gcm/ccs.html
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
//import javax.swing.JScrollPane;
//import javax.swing.SwingUtilities;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.ConnectionConfiguration.SecurityMode;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.PacketInterceptor;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.SmackException;
import org.jivesoftware.smack.SmackException.NotConnectedException;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.DefaultPacketExtension;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;
import org.jivesoftware.smack.util.StringUtils;
import org.json.simple.JSONValue;
import org.json.simple.JSONObject;
import org.json.simple.parser.ParseException;
import org.xmlpull.v1.XmlPullParser;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Random;
import java.net.*;
import java.io.*;
import java.util.*;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.HttpsURLConnection;
// list of all users and associated devices
class UserList {
// (--deleted--)
// constructor/read existing data from file
public UserList() {
// (--deleted--)
}
// add a new device to an existing user (called from networking thread)
// duplicate IDs are quietly accepted
public synchronized void addDevice( String uname, String newRegToken ) {
// (--deleted--)
}
// generate a group address/notification key
// !!!!!!!!!!!!!!! W A R N I N G !!!!!!!!!!!!!!!
// If the group addr/notification key is lost, it currently CANNOT be recovered/rebuilt
public String createNotificationKey( String nKeyName, String addr ) {
String[] idset = new String[1];
idset[0] = addr;
String newGroupAddr;
try {
// create a https connection to create the notification_key
URL url = new URL( "https://android.googleapis.com/gcm/notification" );
HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
// send as a POST request
conn.setRequestMethod("POST");
// add request parameters
conn.addRequestProperty( "project_id", ""+GcmPushServer.senderId );
conn.addRequestProperty( "Authorization", "key="+GcmPushServer.password );
// use "set" since this may already exist
conn.setRequestProperty( "Content-Type", "application/json" );
// create data to send with request
Map<String,Object> sendData = new HashMap<>();
// create a new notification key
sendData.put( "operation", "create" );
sendData.put( "notification_key_name", (--deleted--) );
sendData.put( "registration_ids", (--deleted--) );
String strData = JSONValue.toJSONString(sendData);
// Send post request
conn.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes( strData );
wr.flush();
wr.close();
// successful?
int rc = conn.getResponseCode();
//System.out.println("ResponseCode = " + rc );
// read the response
Scanner input = new Scanner( conn.getInputStream() );
String resp="";
// read/display lines
while( input.hasNextLine() ) {
String s = input.nextLine();
resp += s;
}
//System.out.println("Response content: " + resp);
if ( rc == HttpsURLConnection.HTTP_OK ) {
JSONObject obj = (JSONObject) JSONValue.parse(resp);
newGroupAddr = (String) obj.get( "notification_key" );
//System.out.println(" new notification_key: " + newGroupAddr );
return newGroupAddr;
} else {
}
} catch ( Exception e ) {
//System.out.println("-- Exception: " + e.getMessage() );
}
return null;
}
// add/delete a single address to/from a notification key
// (add if doAdd is true, delete otherwise)
// removing final address will quietly delete the key
public static void modifyNotificationKey( String nKeyName, String nKey,
String addr, boolean doAdd ) {
String[] idset = new String[1];
idset[0] = addr;
try {
// create a https connection to create the notification_key
URL url = new URL( "https://android.googleapis.com/gcm/notification" );
HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
// send as a POST request
conn.setRequestMethod("POST");
// add request parameters
conn.addRequestProperty( "project_id", ""+GcmPushServer.senderId );
conn.addRequestProperty( "Authorization", "key="+GcmPushServer.password );
// use "set" since this may already exist
conn.setRequestProperty( "Content-Type", "application/json" );
// create data to send with request
Map<String,Object> sendData = new HashMap<>();
// create a new notification key
sendData.put( "operation", doAdd? "add" : "remove" ); // add or delete key?
sendData.put( "notification_key_name", (--deleted--) );
sendData.put( "notification_key", (--deleted--) );
sendData.put( "registration_ids", (--deleted--) );
String strData = JSONValue.toJSONString(sendData);
//System.out.println("genGroupAddress POST data: " + strData );
// Send post request
conn.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes( strData );
wr.flush();
wr.close();
//conn.openConnection();
// successful?
int rc = conn.getResponseCode();
//System.out.println("ResponseCode = " + rc );
Scanner input = new Scanner( conn.getInputStream() );
// read/display lines
while( input.hasNextLine() ) {
System.out.println("Response content:");
String s = input.nextLine();
System.out.println( s );
}
} catch ( Exception e ) {
// do nothing
}
}
}
// text area for log messages
class LogTextArea extends JTextArea {
// update the "log" with the specified message
public void logMessage( String msg ) {
// (--deleted--)
}
}
class CcsServer {
private static final String GCM_SERVER = "gcm.googleapis.com";
private static final int GCM_PORT = 5235;
private static final String GCM_ELEMENT_NAME = "gcm";
private static final String GCM_NAMESPACE = "google:mobile:data";
// display/log area
LogTextArea logArea;
UserList users;
CcsServer( LogTextArea lta, UserList u ) {
logArea = lta;
users = u;
}
static {
ProviderManager.addExtensionProvider(GCM_ELEMENT_NAME, GCM_NAMESPACE,
new PacketExtensionProvider() {
#Override
public PacketExtension parseExtension(XmlPullParser parser) throws
Exception {
String json = parser.nextText();
return new GcmPacketExtension(json);
}
});
}
private XMPPConnection connection;
/**
* Indicates whether the connection is in draining state, which means that it
* will not accept any new downstream messages.
*/
protected volatile boolean connectionDraining = false;
/**
* Sends a downstream message to GCM.
*
* #return true if the message has been successfully sent.
*/
public boolean sendDownstreamMessage(String jsonRequest) throws
NotConnectedException {
if (!connectionDraining) {
send(jsonRequest);
return true;
}
logArea.logMessage("Dropping downstream message since the connection is draining");
return false;
}
/**
* Returns a random message id to uniquely identify a message.
*
* <p>Note: This is generated by a pseudo random number generator for
* illustration purpose, and is not guaranteed to be unique.
*/
public String nextMessageId() {
return "m-" + UUID.randomUUID().toString();
}
/**
* Sends a packet with contents provided.
*/
protected void send(String jsonRequest) throws NotConnectedException {
Packet request = new GcmPacketExtension(jsonRequest).toPacket();
connection.sendPacket(request);
}
/**
* Handles an upstream data message from a device application.
*
* <p>This sample echo server sends an echo message back to the device.
* Subclasses should override this method to properly process upstream messages.
*/
protected void handleUpstreamMessage(Map<String, Object> jsonObject) {
// PackageName of the application that sent this message.
String category = (String) jsonObject.get("category");
String from = (String) jsonObject.get("from");
#SuppressWarnings("unchecked")
Map<String, String> payload = (Map<String, String>) jsonObject.get("data");
// what type of upstream message is this?
if ( ! payload.containsKey( "my_action" ) )
{
// Hmmm - this shouldn't happen!
logArea.logMessage( "handleUpstreamMessage - incoming message is missing my_action" );
// just ignore the message
return;
}
// what action do they want?
String my_action = (String) payload.get( "my_action" );
if ( my_action.equals( "edu.eku.styere.gcmpushclient.REGISTER" ) ) {
// registration request
String username = (String) payload.get( "username" );
logArea.logMessage( "Registration request: user=" + username + ", ID/Token=" + from );
// save the information
users.addDevice( username, from );
return;
} else {
// take default action of echoing the message
payload.put("ECHO", "Application: " + category);
// Send an ECHO response back
String echo = createJsonMessage(from, nextMessageId(), payload,
"echo:CollapseKey", null, false);
try {
sendDownstreamMessage(echo);
} catch (NotConnectedException e) {
logArea.logMessage( "Not connected anymore, echo message is not sent: " + e.getMessage() );
}
}
}
/**
* Handles an ACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle ACKs.
*/
protected void handleAckReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logArea.logMessage( "handleAckReceipt() from: " + from + ", messageId: " + messageId );
}
/**
* Handles a NACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle NACKs.
*/
protected void handleNackReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logArea.logMessage( "handleNackReceipt() from: " + from + ", messageId: " + messageId );
}
protected void handleControlMessage(Map<String, Object> jsonObject) {
logArea.logMessage( "handleControlMessage(): " + jsonObject );
String controlType = (String) jsonObject.get("control_type");
if ("CONNECTION_DRAINING".equals(controlType)) {
connectionDraining = true;
} else {
logArea.logMessage( "Unrecognised control type: " + controlType + ". This could "+
"happen if new features are " + "added to the CCS protocol." );
}
}
/**
* Creates a JSON encoded GCM message.
*
* #param to RegistrationId of the target device (Required).
* #param messageId Unique messageId for which CCS sends an
* "ack/nack" (Required).
* #param payload Message content intended for the application. (Optional).
* #param collapseKey GCM collapse_key parameter (Optional).
* #param timeToLive GCM time_to_live parameter (Optional).
* #param delayWhileIdle GCM delay_while_idle parameter (Optional).
* #return JSON encoded GCM message.
*/
public static String createJsonMessage(String to, String messageId,
Map<String, String> payload, String collapseKey, Long timeToLive,
Boolean delayWhileIdle) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("to", to);
if (collapseKey != null) {
message.put("collapse_key", collapseKey);
}
if (timeToLive != null) {
message.put("time_to_live", timeToLive);
}
if (delayWhileIdle != null && delayWhileIdle) {
message.put("delay_while_idle", true);
}
message.put("message_id", messageId);
message.put("data", payload);
return JSONValue.toJSONString(message);
}
/**
* Creates a JSON encoded ACK message for an upstream message received
* from an application.
*
* #param to RegistrationId of the device who sent the upstream message.
* #param messageId messageId of the upstream message to be acknowledged to CCS.
* #return JSON encoded ack.
*/
protected static String createJsonAck(String to, String messageId) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("message_type", "ack");
message.put("to", to);
message.put("message_id", messageId);
return JSONValue.toJSONString(message);
}
/**
* Connects to GCM Cloud Connection Server using the supplied credentials.
*
* #param senderId Your GCM project number
* #param apiKey API Key of your project
*/
public void connect(long senderId, String apiKey)
throws XMPPException, IOException, SmackException {
ConnectionConfiguration config =
new ConnectionConfiguration(GCM_SERVER, GCM_PORT);
config.setSecurityMode(SecurityMode.enabled);
config.setReconnectionAllowed(true);
config.setRosterLoadedAtLogin(false);
config.setSendPresence(false);
config.setSocketFactory(SSLSocketFactory.getDefault());
connection = new XMPPTCPConnection(config);
connection.connect();
connection.addConnectionListener( new LoggingConnectionListener() );
// Handle incoming packets
connection.addPacketListener(new PacketListener() {
#Override
public void processPacket(Packet packet) {
logArea.logMessage( "Received: " + packet.toXML() );
Message incomingMessage = (Message) packet;
GcmPacketExtension gcmPacket =
(GcmPacketExtension) incomingMessage.
getExtension(GCM_NAMESPACE);
String json = gcmPacket.getJson();
try {
#SuppressWarnings("unchecked")
Map<String, Object> jsonObject =
(Map<String, Object>) JSONValue.
parseWithException(json);
// present for "ack"/"nack", null otherwise
Object messageType = jsonObject.get("message_type");
if (messageType == null) {
// Normal upstream data message
handleUpstreamMessage(jsonObject);
// Send ACK to CCS
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
String ack = createJsonAck(from, messageId);
send(ack);
} else if ("ack".equals(messageType.toString())) {
// Process Ack
handleAckReceipt(jsonObject);
} else if ("nack".equals(messageType.toString())) {
// Process Nack
handleNackReceipt(jsonObject);
} else if ("control".equals(messageType.toString())) {
// Process control message
handleControlMessage(jsonObject);
} else {
logArea.logMessage( "Unrecognised message type: " +
messageType.toString() );
}
} catch (ParseException e) {
logArea.logMessage( "Error parsing JSON " + json );
} catch (Exception e) {
logArea.logMessage( "Failed to process packet" );
}
}
}, new PacketTypeFilter(Message.class));
// Log all outgoing packets
connection.addPacketInterceptor(new PacketInterceptor() {
#Override
public void interceptPacket(Packet packet) {
logArea.logMessage( "Sent: " + packet.toXML());
}
}, new PacketTypeFilter(Message.class));
connection.login(senderId + "#gcm.googleapis.com", apiKey);
}
//---------- support classes ----------
/**
* XMPP Packet Extension for GCM Cloud Connection Server.
*/
private static class GcmPacketExtension extends DefaultPacketExtension {
private final String json;
public GcmPacketExtension(String json) {
super( GCM_ELEMENT_NAME, GCM_NAMESPACE);
this.json = json;
}
public String getJson() {
return json;
}
#Override
public String toXML() {
return String.format("<%s xmlns=\"%s\">%s</%s>",
GCM_ELEMENT_NAME, GCM_NAMESPACE,
StringUtils.escapeForXML(json), GCM_ELEMENT_NAME);
}
public Packet toPacket() {
Message message = new Message();
message.addExtension(this);
return message;
}
}
class LoggingConnectionListener implements ConnectionListener {
#Override
public void connected(XMPPConnection xmppConnection) {
logArea.logMessage( "Connected." );
}
#Override
public void authenticated(XMPPConnection xmppConnection) {
logArea.logMessage( "Authenticated." );
}
#Override
public void reconnectionSuccessful() {
logArea.logMessage( "Reconnecting.." );
}
#Override
public void reconnectionFailed(Exception e) {
logArea.logMessage( "Reconnection failed.. " + e.getMessage() );
}
#Override
public void reconnectingIn(int seconds) {
logArea.logMessage( "Reconnecting in " + seconds + " secs" );
}
#Override
public void connectionClosedOnError(Exception e) {
logArea.logMessage( "Connection closed on error." );
}
#Override
public void connectionClosed() {
logArea.logMessage( "Connection closed." );
}
}
}
// a non-editable combo (drop-down) box for destination addresses
class DestComboBox extends JComboBox<String> {
// (deleted to save space)
}
// screen panel for sending a message
class SendMessagePanel extends JPanel implements ActionListener, ItemListener {
// Message Types
protected final int MSGTYPE_NOTIFICATION = 1;
protected final int MSGTYPE_NOTIFICATION_DATA = 2;
protected final int MSGTYPE_DATA_COLLAPSE = 3;
protected final int MSGTYPE_DATA_NONCOLLAPSE = 4;
// log window
LogTextArea msgs;
// server class
CcsServer ccsServer;
// constructor
SendMessagePanel( UserList u, LogTextArea m, CcsServer c ) {
// (deleted to save space)
}
// respond to the button
#Override
public void actionPerformed(ActionEvent e) {
String toAddr = "zzzzzz"; // destination address
// may be device, notification_key, or topic address
ttl = 2419200; // time-to-live in seconds
// what type of message?
int msgTypeIndex = (--deleted--);
// create the message
Map<String, Object> message = new HashMap<String, Object>();
message.put("to", toAddr);
if ( msgTypeIndex == MSGTYPE_NOTIFICATION ||
msgTypeIndex == MSGTYPE_NOTIFICATION_DATA ||
msgTypeIndex == MSGTYPE_DATA_COLLAPSE ) {
// create a collapse key
message.put("collapse_key", "ck"+msgTypeIndex );
}
message.put("time_to_live", ttl);
message.put("message_id", ccsServer.nextMessageId());
// notification included?
if ( msgTypeIndex == MSGTYPE_NOTIFICATION ||
msgTypeIndex == MSGTYPE_NOTIFICATION_DATA ) {
// create the notification payload
HashMap<String, String> notePayload = new HashMap<>();
notePayload.put( "title", "Gcm Push Message Example" );
notePayload.put( "body", (--deleted--) );
// identify which notifications should replace older versions
notePayload.put( "tag", "ntag" + msgTypeIndex );
notePayload.put( "icon", "#drawable/new_picture" ); // notification icon
// additional stuff if we also have data
if ( msgTypeIndex == MSGTYPE_NOTIFICATION_DATA ) {
// what to do when the user opens the notification
notePayload.put( "click_action", "OPEN_MAIN_ACTIVITY" );
}
message.put( "notification", notePayload );
}
// data included?
if ( msgTypeIndex == MSGTYPE_NOTIFICATION_DATA ||
msgTypeIndex == MSGTYPE_DATA_COLLAPSE ||
msgTypeIndex == MSGTYPE_DATA_NONCOLLAPSE ) {
HashMap<String, String> dataPayload = new HashMap<>();
dataPayload.put( "contents", (--deleted--) );
message.put("data", dataPayload);
}
// actually send the message
try {
ccsServer.sendDownstreamMessage( JSONValue.toJSONString(message) );
} catch (NotConnectedException enc ) {
msgs.logMessage( "Not connected anymore, echo message is not sent: " + enc.getMessage() );
}
}
}
class BorderPanel extends JPanel {
// (--deleted--)
}
public class GcmPushServer
{
// (--deleted--)
}

Google's example implementation of an XMPP server is in the friendly-ping sample. It has Java and Go versions.

A little bit late, but here's:
The direct link to the sample app server for ccs connection Friendly Ping java
Wolfram Rittmeyer also created a gcm server, in his An XMPP Server for Google Cloud Messaging post

Could not use Tutorial "Java sample implementing an XMPP-based App Server using the Smack"

From start I'am new to Java Developing... I've tried to use the folowing Java code on NetBeans IDE:
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.ConnectionConfiguration.SecurityMode;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.PacketInterceptor;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.SmackException;
import org.jivesoftware.smack.SmackException.NotConnectedException;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.DefaultPacketExtension;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;
import org.jivesoftware.smack.util.StringUtils;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;
import org.xmlpull.v1.XmlPullParser;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.net.ssl.SSLSocketFactory;
/**
* Sample Smack implementation of a client for GCM Cloud Connection Server. This
* code can be run as a standalone CCS client.
*
* <p>For illustration purposes only.
*/
public class SmackCcsClient {
private static final Logger logger = Logger.getLogger("SmackCcsClient");
private static final String GCM_SERVER = "gcm.googleapis.com";
private static final int GCM_PORT = 5235;
private static final String GCM_ELEMENT_NAME = "gcm";
private static final String GCM_NAMESPACE = "google:mobile:data";
static {
ProviderManager.addExtensionProvider(GCM_ELEMENT_NAME, GCM_NAMESPACE,
new PacketExtensionProvider() {
#Override
public PacketExtension parseExtension(XmlPullParser parser) throws
Exception {
String json = parser.nextText();
return new GcmPacketExtension(json);
}
});
}
private XMPPConnection connection;
/**
* Indicates whether the connection is in draining state, which means that it
* will not accept any new downstream messages.
*/
protected volatile boolean connectionDraining = false;
/**
* Sends a downstream message to GCM.
*
* #return true if the message has been successfully sent.
*/
public boolean sendDownstreamMessage(String jsonRequest) throws
NotConnectedException {
if (!connectionDraining) {
send(jsonRequest);
return true;
}
logger.info("Dropping downstream message since the connection is draining");
return false;
}
/**
* Returns a random message id to uniquely identify a message.
*
* <p>Note: This is generated by a pseudo random number generator for
* illustration purpose, and is not guaranteed to be unique.
*/
public String nextMessageId() {
return "m-" + UUID.randomUUID().toString();
}
/**
* Sends a packet with contents provided.
*/
protected void send(String jsonRequest) throws NotConnectedException {
Packet request = new GcmPacketExtension(jsonRequest).toPacket();
connection.sendPacket(request);
}
/**
* Handles an upstream data message from a device application.
*
* <p>This sample echo server sends an echo message back to the device.
* Subclasses should override this method to properly process upstream messages.
*/
protected void handleUpstreamMessage(Map<String, Object> jsonObject) {
// PackageName of the application that sent this message.
String category = (String) jsonObject.get("category");
String from = (String) jsonObject.get("from");
#SuppressWarnings("unchecked")
Map<String, String> payload = (Map<String, String>) jsonObject.get("data");
payload.put("ECHO", "Application: " + category);
// Send an ECHO response back
String echo = createJsonMessage(from, nextMessageId(), payload,
"echo:CollapseKey", null, false);
try {
sendDownstreamMessage(echo);
} catch (NotConnectedException e) {
logger.log(Level.WARNING, "Not connected anymore, echo message is
not sent", e);
}
}
/**
* Handles an ACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle ACKs.
*/
protected void handleAckReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logger.log(Level.INFO, "handleAckReceipt() from: " + from + ",
messageId: " + messageId);
}
/**
* Handles a NACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle NACKs.
*/
protected void handleNackReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logger.log(Level.INFO, "handleNackReceipt() from: " + from + ",
messageId: " + messageId);
}
protected void handleControlMessage(Map<String, Object> jsonObject) {
logger.log(Level.INFO, "handleControlMessage(): " + jsonObject);
String controlType = (String) jsonObject.get("control_type");
if ("CONNECTION_DRAINING".equals(controlType)) {
connectionDraining = true;
} else {
logger.log(Level.INFO, "Unrecognized control type: %s. This could
happen if new features are " + "added to the CCS protocol.",
controlType);
}
}
/**
* Creates a JSON encoded GCM message.
*
* #param to RegistrationId of the target device (Required).
* #param messageId Unique messageId for which CCS sends an
* "ack/nack" (Required).
* #param payload Message content intended for the application. (Optional).
* #param collapseKey GCM collapse_key parameter (Optional).
* #param timeToLive GCM time_to_live parameter (Optional).
* #param delayWhileIdle GCM delay_while_idle parameter (Optional).
* #return JSON encoded GCM message.
*/
public static String createJsonMessage(String to, String messageId,
Map<String, String> payload, String collapseKey, Long timeToLive,
Boolean delayWhileIdle) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("to", to);
if (collapseKey != null) {
message.put("collapse_key", collapseKey);
}
if (timeToLive != null) {
message.put("time_to_live", timeToLive);
}
if (delayWhileIdle != null && delayWhileIdle) {
message.put("delay_while_idle", true);
}
message.put("message_id", messageId);
message.put("data", payload);
return JSONValue.toJSONString(message);
}
/**
* Creates a JSON encoded ACK message for an upstream message received
* from an application.
*
* #param to RegistrationId of the device who sent the upstream message.
* #param messageId messageId of the upstream message to be acknowledged to CCS.
* #return JSON encoded ack.
*/
protected static String createJsonAck(String to, String messageId) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("message_type", "ack");
message.put("to", to);
message.put("message_id", messageId);
return JSONValue.toJSONString(message);
}
/**
* Connects to GCM Cloud Connection Server using the supplied credentials.
*
* #param senderId Your GCM project number
* #param apiKey API Key of your project
*/
public void connect(long senderId, String apiKey)
throws XMPPException, IOException, SmackException {
ConnectionConfiguration config =
new ConnectionConfiguration(GCM_SERVER, GCM_PORT);
config.setSecurityMode(SecurityMode.enabled);
config.setReconnectionAllowed(true);
config.setRosterLoadedAtLogin(false);
config.setSendPresence(false);
config.setSocketFactory(SSLSocketFactory.getDefault());
connection = new XMPPTCPConnection(config);
connection.connect();
connection.addConnectionListener(new LoggingConnectionListener());
// Handle incoming packets
connection.addPacketListener(new PacketListener() {
#Override
public void processPacket(Packet packet) {
logger.log(Level.INFO, "Received: " + packet.toXML());
Message incomingMessage = (Message) packet;
GcmPacketExtension gcmPacket =
(GcmPacketExtension) incomingMessage.
getExtension(GCM_NAMESPACE);
String json = gcmPacket.getJson();
try {
#SuppressWarnings("unchecked")
Map<String, Object> jsonObject =
(Map<String, Object>) JSONValue.
parseWithException(json);
// present for "ack"/"nack", null otherwise
Object messageType = jsonObject.get("message_type");
if (messageType == null) {
// Normal upstream data message
handleUpstreamMessage(jsonObject);
// Send ACK to CCS
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
String ack = createJsonAck(from, messageId);
send(ack);
} else if ("ack".equals(messageType.toString())) {
// Process Ack
handleAckReceipt(jsonObject);
} else if ("nack".equals(messageType.toString())) {
// Process Nack
handleNackReceipt(jsonObject);
} else if ("control".equals(messageType.toString())) {
// Process control message
handleControlMessage(jsonObject);
} else {
logger.log(Level.WARNING,
"Unrecognized message type (%s)",
messageType.toString());
}
} catch (ParseException e) {
logger.log(Level.SEVERE, "Error parsing JSON " + json, e);
} catch (Exception e) {
logger.log(Level.SEVERE, "Failed to process packet", e);
}
}
}, new PacketTypeFilter(Message.class));
// Log all outgoing packets
connection.addPacketInterceptor(new PacketInterceptor() {
#Override
public void interceptPacket(Packet packet) {
logger.log(Level.INFO, "Sent: {0}", packet.toXML());
}
}, new PacketTypeFilter(Message.class));
connection.login(senderId + "#gcm.googleapis.com", apiKey);
}
public static void main(String[] args) throws Exception {
final long senderId = 1234567890L; // your GCM sender id
final String password = "Your API key";
SmackCcsClient ccsClient = new SmackCcsClient();
ccsClient.connect(senderId, password);
// Send a sample hello downstream message to a device.
String toRegId = "RegistrationIdOfTheTargetDevice";
String messageId = ccsClient.nextMessageId();
Map<String, String> payload = new HashMap<String, String>();
payload.put("Hello", "World");
payload.put("CCS", "Dummy Message");
payload.put("EmbeddedMessageId", messageId);
String collapseKey = "sample";
Long timeToLive = 10000L;
String message = createJsonMessage(toRegId, messageId, payload,
collapseKey, timeToLive, true);
ccsClient.sendDownstreamMessage(message);
}
/**
* XMPP Packet Extension for GCM Cloud Connection Server.
*/
private static final class GcmPacketExtension extends DefaultPacketExtension {
private final String json;
public GcmPacketExtension(String json) {
super(GCM_ELEMENT_NAME, GCM_NAMESPACE);
this.json = json;
}
public String getJson() {
return json;
}
#Override
public String toXML() {
return String.format("<%s xmlns=\"%s\">%s</%s>",
GCM_ELEMENT_NAME, GCM_NAMESPACE,
StringUtils.escapeForXML(json), GCM_ELEMENT_NAME);
}
public Packet toPacket() {
Message message = new Message();
message.addExtension(this);
return message;
}
}
private static final class LoggingConnectionListener
implements ConnectionListener {
#Override
public void connected(XMPPConnection xmppConnection) {
logger.info("Connected.");
}
#Override
public void authenticated(XMPPConnection xmppConnection) {
logger.info("Authenticated.");
}
#Override
public void reconnectionSuccessful() {
logger.info("Reconnecting..");
}
#Override
public void reconnectionFailed(Exception e) {
logger.log(Level.INFO, "Reconnection failed.. ", e);
}
#Override
public void reconnectingIn(int seconds) {
logger.log(Level.INFO, "Reconnecting in %d secs", seconds);
}
#Override
public void connectionClosedOnError(Exception e) {
logger.info("Connection closed on error.");
}
#Override
public void connectionClosed() {
logger.info("Connection closed.");
}
}
}
Source code I found on following link:
http://developer.android.com/google/gcm/ccs.html#implement
I imported already Smack 4.1.1 on it and also json-simple-1.1.1, xmlpull-1.1.3.1, junit...
Problem lyies on Smack library, iam getting a lot of errors, even i already imported all jar files from it... I understand that Smack library is having a BIG history during development... still i would like to understand what I'am doing... Found a possible solution on following link:
GCM XMPP Server using Smack 4.1.0
Maybe I can use it, maybe not... Are there any Tutorials? Maybe some better examples? Is every version on Smack having it's own Documentation?

build.gradle(Module: app)
apply plugin: 'com.android.application'
android {
compileSdkVersion 22
buildToolsVersion "22.0.1"
defaultConfig {
applicationId "com.example.sqltest2"
minSdkVersion 16
targetSdkVersion 22
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.1.1'
compile 'com.google.android.gms:play-services:7.3.0'
compile "org.igniterealtime.smack:smack-android:4.1.0-rc1"
compile "org.igniterealtime.smack:smack-tcp:4.1.0-rc1"
compile "org.igniterealtime.smack:smack-extensions:4.1.0-rc1"
compile "org.igniterealtime.smack:smack-im:4.1.0-rc1"
}

java.lang.NoClassDefFoundError when trying to run SmackCcsClient for CCS

I am trying to make third party server so that I can implement CCS server for my chat client. I copied the below code from below android developer link, I included Smack library and JSON library as prescribed, however I am getting compilation error.
CCS Link
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.ConnectionConfiguration.SecurityMode;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.PacketInterceptor;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.SmackException;
import org.jivesoftware.smack.SmackException.NotConnectedException;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.DefaultPacketExtension;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;
import org.jivesoftware.smack.util.StringUtils;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;
import org.xmlpull.v1.XmlPullParser;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.net.ssl.SSLSocketFactory;
Sample implementation:
/**
* Sample Smack implementation of a client for GCM Cloud Connection Server. This
* code can be run as a standalone CCS client.
*
* <p>For illustration purposes only.
*/
public class SmackCcsClient {
private static final Logger logger = Logger.getLogger("SmackCcsClient");
private static final String GCM_SERVER = "gcm.googleapis.com";
private static final int GCM_PORT = 5235;
private static final String GCM_ELEMENT_NAME = "gcm";
private static final String GCM_NAMESPACE = "google:mobile:data";
static {
ProviderManager.addExtensionProvider(GCM_ELEMENT_NAME, GCM_NAMESPACE,
new PacketExtensionProvider() {
#Override
public PacketExtension parseExtension(XmlPullParser parser) throws
Exception {
String json = parser.nextText();
return new GcmPacketExtension(json);
}
});
}
private XMPPConnection connection;
/**
* Indicates whether the connection is in draining state, which means that it
* will not accept any new downstream messages.
*/
protected volatile boolean connectionDraining = false;
/**
* Sends a downstream message to GCM.
*
* #return true if the message has been successfully sent.
*/
public boolean sendDownstreamMessage(String jsonRequest) throws
NotConnectedException {
if (!connectionDraining) {
send(jsonRequest);
return true;
}
logger.info("Dropping downstream message since the connection is draining");
return false;
}
/**
* Returns a random message id to uniquely identify a message.
*
* <p>Note: This is generated by a pseudo random number generator for
* illustration purpose, and is not guaranteed to be unique.
*/
public String nextMessageId() {
return "m-" + UUID.randomUUID().toString();
}
/**
* Sends a packet with contents provided.
*/
protected void send(String jsonRequest) throws NotConnectedException {
Packet request = new GcmPacketExtension(jsonRequest).toPacket();
connection.sendPacket(request);
}
/**
* Handles an upstream data message from a device application.
*
* <p>This sample echo server sends an echo message back to the device.
* Subclasses should override this method to properly process upstream messages.
*/
protected void handleUpstreamMessage(Map<String, Object> jsonObject) {
// PackageName of the application that sent this message.
String category = (String) jsonObject.get("category");
String from = (String) jsonObject.get("from");
#SuppressWarnings("unchecked")
Map<String, String> payload = (Map<String, String>) jsonObject.get("data");
payload.put("ECHO", "Application: " + category);
// Send an ECHO response back
String echo = createJsonMessage(from, nextMessageId(), payload,
"echo:CollapseKey", null, false);
try {
sendDownstreamMessage(echo);
} catch (NotConnectedException e) {
logger.log(Level.WARNING, "Not connected anymore, echo message is not sent", e);
}
}
/**
* Handles an ACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle ACKs.
*/
protected void handleAckReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logger.log(Level.INFO, "handleAckReceipt() from: " + from + ",messageId: " + messageId);
}
/**
* Handles a NACK.
*
* <p>Logs a INFO message, but subclasses could override it to
* properly handle NACKs.
*/
protected void handleNackReceipt(Map<String, Object> jsonObject) {
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
logger.log(Level.INFO, "handleNackReceipt() from: " + from + ",messageId: " + messageId);
}
protected void handleControlMessage(Map<String, Object> jsonObject) {
logger.log(Level.INFO, "handleControlMessage(): " + jsonObject);
String controlType = (String) jsonObject.get("control_type");
if ("CONNECTION_DRAINING".equals(controlType)) {
connectionDraining = true;
} else {
logger.log(Level.INFO, "Unrecognized control type: %s. This could happen if new features are " + "added to the CCS protocol.",controlType);
}
}
/**
* Creates a JSON encoded GCM message.
*
* #param to RegistrationId of the target device (Required).
* #param messageId Unique messageId for which CCS will send an
* "ack/nack" (Required).
* #param payload Message content intended for the application. (Optional).
* #param collapseKey GCM collapse_key parameter (Optional).
* #param timeToLive GCM time_to_live parameter (Optional).
* #param delayWhileIdle GCM delay_while_idle parameter (Optional).
* #return JSON encoded GCM message.
*/
public static String createJsonMessage(String to, String messageId,
Map<String, String> payload, String collapseKey, Long timeToLive,
Boolean delayWhileIdle) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("to", to);
if (collapseKey != null) {
message.put("collapse_key", collapseKey);
}
if (timeToLive != null) {
message.put("time_to_live", timeToLive);
}
if (delayWhileIdle != null && delayWhileIdle) {
message.put("delay_while_idle", true);
}
message.put("message_id", messageId);
message.put("data", payload);
return JSONValue.toJSONString(message);
}
/**
* Creates a JSON encoded ACK message for an upstream message received
* from an application.
*
* #param to RegistrationId of the device who sent the upstream message.
* #param messageId messageId of the upstream message to be acknowledged to CCS.
* #return JSON encoded ack.
*/
protected static String createJsonAck(String to, String messageId) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("message_type", "ack");
message.put("to", to);
message.put("message_id", messageId);
return JSONValue.toJSONString(message);
}
/**
* Connects to GCM Cloud Connection Server using the supplied credentials.
*
* #param senderId Your GCM project number
* #param apiKey API Key of your project
*/
public void connect(long senderId, String apiKey)
throws XMPPException, IOException, SmackException {
ConnectionConfiguration config =
new ConnectionConfiguration(GCM_SERVER, GCM_PORT);
config.setSecurityMode(SecurityMode.enabled);
config.setReconnectionAllowed(true);
config.setRosterLoadedAtLogin(false);
config.setSendPresence(false);
config.setSocketFactory(SSLSocketFactory.getDefault());
connection = new XMPPTCPConnection(config);
connection.connect();
connection.addConnectionListener(new LoggingConnectionListener());
// Handle incoming packets
connection.addPacketListener(new PacketListener() {
#Override
public void processPacket(Packet packet) {
logger.log(Level.INFO, "Received: " + packet.toXML());
Message incomingMessage = (Message) packet;
GcmPacketExtension gcmPacket =
(GcmPacketExtension) incomingMessage.
getExtension(GCM_NAMESPACE);
String json = gcmPacket.getJson();
try {
#SuppressWarnings("unchecked")
Map<String, Object> jsonObject =
(Map<String, Object>) JSONValue.
parseWithException(json);
// present for "ack"/"nack", null otherwise
Object messageType = jsonObject.get("message_type");
if (messageType == null) {
// Normal upstream data message
handleUpstreamMessage(jsonObject);
// Send ACK to CCS
String messageId = (String) jsonObject.get("message_id");
String from = (String) jsonObject.get("from");
String ack = createJsonAck(from, messageId);
send(ack);
} else if ("ack".equals(messageType.toString())) {
// Process Ack
handleAckReceipt(jsonObject);
} else if ("nack".equals(messageType.toString())) {
// Process Nack
handleNackReceipt(jsonObject);
} else if ("control".equals(messageType.toString())) {
// Process control message
handleControlMessage(jsonObject);
} else {
logger.log(Level.WARNING,
"Unrecognized message type (%s)",
messageType.toString());
}
} catch (ParseException e) {
logger.log(Level.SEVERE, "Error parsing JSON " + json, e);
} catch (Exception e) {
logger.log(Level.SEVERE, "Failed to process packet", e);
}
}
}, new PacketTypeFilter(Message.class));
// Log all outgoing packets
connection.addPacketInterceptor(new PacketInterceptor() {
#Override
public void interceptPacket(Packet packet) {
logger.log(Level.INFO, "Sent: {0}", packet.toXML());
}
}, new PacketTypeFilter(Message.class));
connection.login(senderId + "#gcm.googleapis.com", apiKey);
}
public static void main(String[] args) throws Exception {
final long senderId = 1234567890L; // your GCM sender id
final String password = "Your API key";
SmackCcsClient ccsClient = new SmackCcsClient();
ccsClient.connect(senderId, password);
// Send a sample hello downstream message to a device.
String toRegId = "RegistrationIdOfTheTargetDevice";
String messageId = ccsClient.nextMessageId();
Map<String, String> payload = new HashMap<String, String>();
payload.put("Hello", "World");
payload.put("CCS", "Dummy Message");
payload.put("EmbeddedMessageId", messageId);
String collapseKey = "sample";
Long timeToLive = 10000L;
String message = createJsonMessage(toRegId, messageId, payload,
collapseKey, timeToLive, true);
ccsClient.sendDownstreamMessage(message);
}
/**
* XMPP Packet Extension for GCM Cloud Connection Server.
*/
private static final class GcmPacketExtension extends DefaultPacketExtension {
private final String json;
public GcmPacketExtension(String json) {
super(GCM_ELEMENT_NAME, GCM_NAMESPACE);
this.json = json;
}
public String getJson() {
return json;
}
public String toXML() {
return String.format("<%s xmlns=\"%s\">%s</%s>",
GCM_ELEMENT_NAME, GCM_NAMESPACE,
StringUtils.escapeForXML(json), GCM_ELEMENT_NAME);
}
public Packet toPacket() {
Message message = new Message();
message.addExtension(this);
return message;
}
}
private static final class LoggingConnectionListener
implements ConnectionListener {
public void connected(XMPPConnection xmppConnection) {
logger.info("Connected.");
}
public void authenticated(XMPPConnection xmppConnection) {
logger.info("Authenticated.");
}
public void reconnectionSuccessful() {
logger.info("Reconnecting..");
}
public void reconnectionFailed(Exception e) {
logger.log(Level.INFO, "Reconnection failed.. ", e);
}
public void reconnectingIn(int seconds) {
logger.log(Level.INFO, "Reconnecting in %d secs", seconds);
}
public void connectionClosedOnError(Exception e) {
logger.info("Connection closed on error.");
}
public void connectionClosed() {
logger.info("Connection closed.");
}
}
}
Once I try to run it with using the below command
java SmackCcsClient
it gives me the below error stack.
Exception in thread "main" java.lang.NoClassDefFoundError: org/jivesoftware/smack/SmackException$NotConnectedException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2531)
at java.lang.Class.getMethod0(Class.java:2774)
at java.lang.Class.getMethod(Class.java:1663)
at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:494)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:486)
Caused by: java.lang.ClassNotFoundException: org.jivesoftware.smack.SmackException$NotConnectedException
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 6 more

ClassNotFoundException on the server when reading from ObjectInputStream

Based on this tutorial and another tutorial that unfortunately I can't get my hands on right now, I've created my Client-Server application but instead of sending string messages, the client asks for data(using Object Input/Output Streams) from the server using a custom class "Message".
First I created, the basic concept of it, using simple Java and tested both the server and the client on my computer, and displayed the data my client received in the console output. Everything worked out great, so I started to make the transition to Android(for the client). Trying to use the AsycTask, as show in the linked tutorial, I've managed so far to establish the connection between the client and the server. But I'm having a problem getting my server to read my "Message" object. Here are my classes:
Server:
import java.io.*;
import java.net.*;
import java.util.logging.Level;
import java.util.logging.Logger;
public class T_Server extends Thread {
private static int port = 4444;
private ServerSocket srvSock = null;
private Socket clntSock = null;
private boolean running = false;
private ObjectInputStream in;
private ObjectOutputStream out;
private OnMessageReceived msgListener;
private Message msgIn;
private Object objSend;
public static void main(String[] args) {
OnMessageReceived _msgListener=new OnMessageReceived();
T_Server server=new T_Server(_msgListener);
server.start();
}
public T_Server(OnMessageReceived _msgListener) {
this.msgListener = _msgListener;
}
public void send(Object _msg) {
if (out != null) {
try {
out.writeObject(_msg);
out.flush();
} catch (IOException ex) {
Logger.getLogger(T_Server.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
#Override
public void run() {
running = true;
try {
srvSock = new ServerSocket(port);
System.out.println("Server startet. IP : " + InetAddress.getLocalHost() + ", Port : " + srvSock.getLocalPort());
System.out.println("\nWaiting for a client ...");
clntSock = srvSock.accept();
System.out.println("\nClient accepted: " + clntSock);
try {
out = new ObjectOutputStream(clntSock.getOutputStream());
in = new ObjectInputStream(clntSock.getInputStream());
while (running) {
msgIn = (Message) in.readObject();
System.out.println(msgIn.toString());
objSend = msgListener.messageReceived(msgIn);
send(objSend);
}
} catch (Exception e) {
System.out.println("S: Error");
e.printStackTrace();
} finally {
clntSock.close();
}
} catch (Exception e) {
System.out.println("S: Error");
e.printStackTrace();
}
}
}
I use the same Message class both on the Server and on the Client
Message Class:
import java.io.Serializable;
public class Message implements Serializable{
private static final long serialVersionUID = 1L;
public String sender, content, type;
public Message(String sender, String type, String content){
this.sender = sender; this.type=type; this.content = content;
}
#Override
public String toString(){
return "{type='"+type+"', sender='"+sender+"', content='"+content+"'}";
}
}
I have also created a class to handle the Messages, on the server side, called OnMessageReceived.
P.S. In this class there are fields and some options that have to do with my backend database.
OnMessageReceived:
import java.sql.SQLException;
import java.util.regex.Pattern;
public class OnMessageReceived {
public Object messageReceived(Message message) throws SQLException {
Message _msg = message;
Database db = new Database();
Object objReturn;
String strResult;
boolean addResult;
final Pattern pattern = Pattern.compile("\\[.*?&");
final String[] result;
if (_msg.type.equals("getUsers")) {
objReturn = db.getUsers();
return objReturn;
} else if (_msg.type.equals("getFriends")) {
objReturn = db.getFriends(_msg.sender);
return objReturn;
} else if (_msg.type.equals("addFriend")) {
String _UserName, _UserNameFriend;
_UserName = _msg.sender;
_UserNameFriend = _msg.content;
addResult = db.addFriend(_UserName, _UserNameFriend);
if (addResult) {
strResult = "Add was successfull";
return strResult;
} else if (!addResult) {
strResult = "Add failed";
return strResult;
}
System.out.println(addResult);
} else if (_msg.type.equals("addUser")) {
String _UserName, _Password, _Phone;
result = pattern.split(_msg.content);
_UserName = _msg.sender;
_Password = result[0];
_Phone = result[1];
addResult = db.addUser(_UserName, _Password, _Phone);
if (addResult) {
strResult = "Add was successfull";
return strResult;
} else if (!addResult) {
strResult = "Add failed";
return strResult;
}
System.out.println(addResult);
} else if (_msg.type.equals("Login")) {
boolean isUser;
String _UserName;
_UserName = _msg.sender;
isUser = db.isUser(_UserName);
if (isUser) {
strResult = "Login Successfull";
return strResult;
} else if (!isUser) {
strResult = "Login failed";
return strResult;
}
}
return null;
}
}
For the client side(on the Android) it's very simillar to the one in the linked tutorial.
The difference is that I only have 2 buttons, one to connect to the server and one to send my message, which is an instance of my Message class.
Client:
import java.io.*;
import java.net.*;
import android.util.Log;
public class T_Client {
private static final String TAG = "MyActivity";
private static String serverIP = "192.168.1.11";
private static int port = 4444;
private InetAddress serverAddr = null;
private Socket sock = null;
private boolean running = false;
private ObjectInputStream in;
private ObjectOutputStream out;
private OnMessageReceived msgListener;
Object objIn, objReceived;
public T_Client(OnMessageReceived _msgListener){
this.msgListener=_msgListener;
}
public void send(Message _msg) {
if (out != null) {
try {
out.writeObject(_msg);
out.flush();
Log.i(TAG,"Outgoing : " + _msg.toString());
} catch (IOException ex) {
Log.e(TAG,ex.toString());
}
}
}
public void stopClient(){
running = false;
}
public void run(){
running = true;
try {
//here you must put your computer's IP address.
serverAddr = InetAddress.getByName(serverIP);
Log.i("TCP Client", "C: Connecting...");
//create a socket to make the connection with the server
sock = new Socket(serverAddr, port);
try {
//send the message to the server
out =new ObjectOutputStream(sock.getOutputStream());
//receive the message which the server sends back
in =new ObjectInputStream(sock.getInputStream());
Log.i("TCP Client", "C: Connected.");
//in this while the client listens for the messages sent by the server
while (running) {
objIn = in.readObject();
if (objIn != null && msgListener != null) {
//call the method messageReceived from MyActivity class
msgListener.messageReceived(objIn);
}
objIn = null;
}
Log.e("RESPONSE FROM SERVER", "S: Received Message: '" + objIn + "'");
} catch (Exception e) {
Log.e("TCP", "S: Error", e);
} finally {
//the socket must be closed. It is not possible to reconnect to this socket
// after it is closed, which means a new socket instance has to be created.
sock.close();
}
} catch (Exception e) {
Log.e("TCP", "C: Error", e);
}
}
public interface OnMessageReceived {
public void messageReceived(Object objReceived);
}
}
Main Activity:
import java.io.IOException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.View;
public class MainActivity extends Activity {
private static final String TAG = "MyActivity";
private T_Client client;
private Message msgSend;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void connect(View v) throws IOException {
new connectTask().execute("");
}
public void btnSend(View v) throws IOException {
msgSend=new Message("Setlios", "getUsers", "");
if(client!=null){
client.send(msgSend);
}
}
public class connectTask extends AsyncTask<Object,Object,T_Client> {
#Override
protected T_Client doInBackground(Object... objIn) {
//we create a TCPClient object and
client = new T_Client(new T_Client.OnMessageReceived() {
#Override
//here the messageReceived method is implemented
public void messageReceived(Object objIn) {
//this method calls the onProgressUpdate
publishProgress(objIn);
}
});
client.run();
return null;
}
#Override
protected void onProgressUpdate(Object... values) {
super.onProgressUpdate(values);
Log.i(TAG,values.getClass().getName().toString());
}
}
}
When I hit the "Send" button I get this error on the server console which points me to the point where I read the object read from the ObjectInputStream and pass it an instance of the Message class but I can't understand what the problem is. I also noticed that it shows this "in.neverhide.connect" which is the package name of the project for my android client
java.lang.ClassNotFoundException: in.neverhide.connect.Message
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:622)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1593)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1514)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1750)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1347)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:369)
at Objects_WORKING.T_Server.run(T_Server.java:61)

Ok after searching around I found this post and the answer from Akinsola 'mys Tunmise. I've made the Message class into a jar and used it as an external reference in both the client and the server.

Running a Client-Server Chat program

This is one of the most common application scenario that can be found all over the net. and I'm not asking any questions about the java codes that I did because I was successful in running it on my laptop where both the client and server part of the .java file resides. Rather I have had problem getting it to work in between two computers. I tried establishing physical connection using cross-over cable to connect two computers, and did a test to see if file transfers successfully and it did, however, keeping one Server part of the .java file in one computer and client part in the other, I tried to run the server first and then the client but it got a "access denied" error.
For reference here's my two .java files:
/* ChatClient.java */
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class ChatClient {
private static int port = 5000; /* port to connect to */
private static String host = "localhost"; /* host to connect to (server's IP)*/
private static BufferedReader stdIn;
private static String nick;
/**
* Read in a nickname from stdin and attempt to authenticate with the
* server by sending a NICK command to #out. If the response from #in
* is not equal to "OK" go bacl and read a nickname again
*/
private static String getNick(BufferedReader in,
PrintWriter out) throws IOException {
System.out.print("Enter your nick: ");
String msg = stdIn.readLine();
out.println("NICK " + msg);
String serverResponse = in.readLine();
if ("SERVER: OK".equals(serverResponse)) return msg;
System.out.println(serverResponse);
return getNick(in, out);
}
public static void main (String[] args) throws IOException {
Socket server = null;
try {
server = new Socket(host, port);
} catch (UnknownHostException e) {
System.err.println(e);
System.exit(1);
}
stdIn = new BufferedReader(new InputStreamReader(System.in));
/* obtain an output stream to the server... */
PrintWriter out = new PrintWriter(server.getOutputStream(), true);
/* ... and an input stream */
BufferedReader in = new BufferedReader(new InputStreamReader(
server.getInputStream()));
nick = getNick(in, out);
/* create a thread to asyncronously read messages from the server */
ServerConn sc = new ServerConn(server);
Thread t = new Thread(sc);
t.start();
String msg;
/* loop reading messages from stdin and sending them to the server */
while ((msg = stdIn.readLine()) != null) {
out.println(msg);
}
}
}
class ServerConn implements Runnable {
private BufferedReader in = null;
public ServerConn(Socket server) throws IOException {
/* obtain an input stream from the server */
in = new BufferedReader(new InputStreamReader(
server.getInputStream()));
}
public void run() {
String msg;
try {
/* loop reading messages from the server and show them
* on stdout */
while ((msg = in.readLine()) != null) {
System.out.println(msg);
}
} catch (IOException e) {
System.err.println(e);
}
}
}
and here's the ChatServer.java:
/* ChatServer.java */
import java.net.ServerSocket;
import java.net.Socket;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Hashtable;
public class ChatServer {
private static int port = 5000; /* port to listen on */
public static void main (String[] args) throws IOException
{
ServerSocket server = null;
try {
server = new ServerSocket(port); /* start listening on the port */
} catch (IOException e) {
System.err.println("Could not listen on port: " + port);
System.err.println(e);
System.exit(1);
}
Socket client = null;
while(true) {
try {
client = server.accept();
} catch (IOException e) {
System.err.println("Accept failed.");
System.err.println(e);
System.exit(1);
}
/* start a new thread to handle this client */
Thread t = new Thread(new ClientConn(client));
t.start();
}
}
}
class ChatServerProtocol {
private String nick;
private ClientConn conn;
/* a hash table from user nicks to the corresponding connections */
private static Hashtable<String, ClientConn> nicks =
new Hashtable<String, ClientConn>();
private static final String msg_OK = "OK";
private static final String msg_NICK_IN_USE = "NICK IN USE";
private static final String msg_SPECIFY_NICK = "SPECIFY NICK";
private static final String msg_INVALID = "INVALID COMMAND";
private static final String msg_SEND_FAILED = "FAILED TO SEND";
/**
* Adds a nick to the hash table
* returns false if the nick is already in the table, true otherwise
*/
private static boolean add_nick(String nick, ClientConn c) {
if (nicks.containsKey(nick)) {
return false;
} else {
nicks.put(nick, c);
return true;
}
}
public ChatServerProtocol(ClientConn c) {
nick = null;
conn = c;
}
private void log(String msg) {
System.err.println(msg);
}
public boolean isAuthenticated() {
return ! (nick == null);
}
/**
* Implements the authentication protocol.
* This consists of checking that the message starts with the NICK command
* and that the nick following it is not already in use.
* returns:
* msg_OK if authenticated
* msg_NICK_IN_USE if the specified nick is already in use
* msg_SPECIFY_NICK if the message does not start with the NICK command
*/
private String authenticate(String msg) {
if(msg.startsWith("NICK")) {
String tryNick = msg.substring(5);
if(add_nick(tryNick, this.conn)) {
log("Nick " + tryNick + " joined.");
this.nick = tryNick;
return msg_OK;
} else {
return msg_NICK_IN_USE;
}
} else {
return msg_SPECIFY_NICK;
}
}
/**
* Send a message to another user.
* #recepient contains the recepient's nick
* #msg contains the message to send
* return true if the nick is registered in the hash, false otherwise
*/
private boolean sendMsg(String recipient, String msg) {
if (nicks.containsKey(recipient)) {
ClientConn c = nicks.get(recipient);
c.sendMsg(nick + ": " + msg);
return true;
} else {
return false;
}
}
/**
* Process a message coming from the client
*/
public String process(String msg) {
if (!isAuthenticated())
return authenticate(msg);
String[] msg_parts = msg.split(" ", 3);
String msg_type = msg_parts[0];
if(msg_type.equals("MSG")) {
if(msg_parts.length < 3) return msg_INVALID;
if(sendMsg(msg_parts[1], msg_parts[2])) return msg_OK;
else return msg_SEND_FAILED;
} else {
return msg_INVALID;
}
}
}
class ClientConn implements Runnable {
private Socket client;
private BufferedReader in = null;
private PrintWriter out = null;
ClientConn(Socket client) {
this.client = client;
try {
/* obtain an input stream to this client ... */
in = new BufferedReader(new InputStreamReader(
client.getInputStream()));
/* ... and an output stream to the same client */
out = new PrintWriter(client.getOutputStream(), true);
} catch (IOException e) {
System.err.println(e);
return;
}
}
public void run() {
String msg, response;
ChatServerProtocol protocol = new ChatServerProtocol(this);
try {
/* loop reading lines from the client which are processed
* according to our protocol and the resulting response is
* sent back to the client */
while ((msg = in.readLine()) != null) {
response = protocol.process(msg);
out.println("SERVER: " + response);
}
} catch (IOException e) {
System.err.println(e);
}
}
public void sendMsg(String msg) {
out.println(msg);
}
}
Now, what should I do in order to run this two files from two computers given that I have the physical connection(TCP/IP) setup already??
Thanks in advance... :)

Sounds like it's quite possibly a firewall problem. Have you tried opening a hole in your firewall for port 1001?

Have you also looked at your java.policy and make sure that it is configured to allow local codebase to open sockets?

as mentioned in comment, you should not use port < 1025 for you applications, since they are always used in deamon processes. However you should test your program like this
1) if you get connection refused then you should check the exception properly, whether client program takes time before generating exception ( that mean request is going to server and then it's giving connection refused), in that case you should try java.policy put following in a file named java.policy
grant {
permission java.net.SocketPermission ":1024-65535",
"connect,accept";
permission java.net.SocketPermission ":80", "connect";
permission java.io.FilePermission "", "read,write,delete";
permission java.security.SecurityPermission "";
};
while compiling use this flag -Djava.security.policy=java.policy
more-over you should also try -Djava.rmi.server.hostname=IP, where IP is clien-ip for client.java and server-ip for server.java
2) if you are immediately getting exception at client side then your request is not going outside your pc, so client has some problem.
check the exception properly and post them over here.
3) though i've not got access denied error, but it seems to have port problem that might be solved using policy or port>1024.
post what are you getting now.