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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
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package org.apache.cayenne.event;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Collection;
import java.util.Collections;
import org.jivesoftware.smack.GroupChat;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.SSLXMPPConnection;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.util.Base64Codec;
import org.apache.cayenne.util.Util;
/**
* An EventBridge implementation based on XMPP protocol and Smack XMPP client library.
* What's good about XMPP (Extensible Messaging and Presence Protocol, an IETF standard
* protocol that grew up from Jabber IM) is that generally it has fewer or no deployment
* limitations (unlike JMS and JGroups that are generally a good solution for local
* controlled networks). Also it provides lots of additional information for free, such as
* presence, and much more.
* <p>
* This implementation is based on Smack XMPP client library from JiveSoftware.
* </p>
*
* @since 1.2
*/
public class XMPPBridge extends EventBridge {
static final String DEFAULT_CHAT_SERVICE = "conference";
static final int DEFAULT_XMPP_PORT = 5222;
static final int DEFAULT_XMPP_SECURE_PORT = 5223;
protected boolean secureConnection;
protected String loginId;
protected String password;
protected String xmppHost;
protected int xmppPort;
protected String chatService;
protected String sessionHandle;
protected XMPPConnection connection;
protected GroupChat groupChat;
protected boolean connected;
/**
* Creates an XMPPBridge. External subject will be used as the chat group name.
*/
public XMPPBridge(EventSubject localSubject, String externalSubject) {
this(Collections.singleton(localSubject), externalSubject);
}
/**
* Creates an XMPPBridge. External subject will be used as the chat group name.
*/
public XMPPBridge(Collection<EventSubject> localSubjects, String externalSubject) {
super(localSubjects, externalSubject);
// generate a unique session handle... users can override it to use a specific
// handle...
this.sessionHandle = "cayenne-xmpp-" + System.currentTimeMillis();
}
public String getXmppHost() {
return xmppHost;
}
public void setXmppHost(String xmppHost) {
this.xmppHost = xmppHost;
}
public int getXmppPort() {
return xmppPort;
}
public void setXmppPort(int xmppPort) {
this.xmppPort = xmppPort;
}
public String getLoginId() {
return loginId;
}
public void setLoginId(String loginId) {
this.loginId = loginId;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean isSecureConnection() {
return secureConnection;
}
public void setSecureConnection(boolean secureConnection) {
this.secureConnection = secureConnection;
}
public String getChatService() {
return chatService;
}
public void setChatService(String chatService) {
this.chatService = chatService;
}
public String getSessionHandle() {
return sessionHandle;
}
public void setSessionHandle(String sessionHandle) {
this.sessionHandle = sessionHandle;
}
@Override
protected void startupExternal() throws Exception {
// validate settings
if (xmppHost == null) {
throw new CayenneRuntimeException("Null 'xmppHost', can't start XMPPBridge");
}
// shutdown old bridge
if (connected) {
shutdownExternal();
}
try {
// connect and log in to chat
if (secureConnection) {
int port = xmppPort > 0 ? xmppPort : DEFAULT_XMPP_SECURE_PORT;
this.connection = new SSLXMPPConnection(xmppHost, port);
}
else {
int port = xmppPort > 0 ? xmppPort : DEFAULT_XMPP_PORT;
this.connection = new XMPPConnection(xmppHost, port);
}
if (loginId != null) {
// it is important to provide a (pseudo) globally unique string as the
// third argument ("sessionHandle" is such string); without it same
// loginId can not be reused from the same machine.
connection.login(loginId, password, sessionHandle);
}
else {
connection.loginAnonymously();
}
}
catch (XMPPException e) {
throw new CayenneRuntimeException("Error connecting to XMPP Server"
+ e.getLocalizedMessage());
}
String service = this.chatService != null
? this.chatService
: DEFAULT_CHAT_SERVICE;
try {
this.groupChat = connection.createGroupChat(externalSubject
+ '@'
+ service
+ "."
+ connection.getHost());
groupChat.join(sessionHandle);
groupChat.addMessageListener(new XMPPListener());
}
catch (XMPPException e) {
throw new CayenneRuntimeException("Error setting up a group chat: "
+ e.getLocalizedMessage());
}
this.connected = true;
}
@Override
protected void shutdownExternal() throws Exception {
if (groupChat != null) {
groupChat.leave();
groupChat = null;
}
if (connection != null) {
connection.close();
connection = null;
}
connected = false;
}
@Override
protected void sendExternalEvent(CayenneEvent localEvent) throws Exception {
Message message = groupChat.createMessage();
message.setBody(serializeToString(localEvent));
// set thread to our session handle to be able to discard messages from self
message.setThread(sessionHandle);
groupChat.sendMessage(message);
}
class XMPPListener implements PacketListener {
public void processPacket(Packet packet) {
if (packet instanceof Message) {
Message message = (Message) packet;
// filter our own messages
if (sessionHandle.equals(message.getThread())) {
// discarding
}
else {
String payload = message.getBody();
try {
Object event = deserializeFromString(payload);
if (event instanceof CayenneEvent) {
onExternalEvent((CayenneEvent) event);
}
}
catch (Exception ex) {
// ignore for now... need to add logging.
}
}
}
}
}
/**
* Decodes the String (assuming it is using Base64 encoding), and then deserializes
* object from the byte array.
*/
static Object deserializeFromString(String string) throws Exception {
if (Util.isEmptyString(string)) {
return null;
}
byte[] bytes = Base64Codec.decodeBase64(string.getBytes());
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(bytes));
Object object = in.readObject();
in.close();
return object;
}
/**
* Serializes object and then encodes it using Base64 encoding.
*/
static String serializeToString(Object object) throws Exception {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bytes);
out.writeObject(object);
out.close();
return new String(Base64Codec.encodeBase64(bytes.toByteArray()));
}
}