javax.mail.Service Maven / Gradle / Ivy
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package javax.mail;
import java.net.*;
import java.util.*;
import java.util.concurrent.Executor;
import javax.mail.event.*;
/**
* An abstract class that contains the functionality common to messaging services, such as stores and transports.
*
* A messaging service is created from a Session and is named using a URLName. A service must be connected before it can be used. Connection events are sent to reflect its
* connection status.
*
* @author Christopher Cotton
* @author Bill Shannon
* @author Kanwar Oberoi
*/
public abstract class Service implements AutoCloseable {
/**
* The session from which this service was created.
*/
protected Session session;
/**
* The URLName of this service.
*/
protected volatile URLName url = null;
/**
* Debug flag for this service. Set from the session's debug flag when this service is created.
*/
protected boolean debug = false;
private boolean connected = false;
/*
* connectionListeners is a Vector, initialized here, because we depend on it always existing and depend on the synchronization that Vector provides. (Sychronizing on the Service object itself can
* cause deadlocks when notifying listeners.)
*/
private final Vector connectionListeners = new Vector<>();
/**
* The queue of events to be delivered.
*/
private final EventQueue q;
/**
* Constructor.
*
* @param session Session object for this service
* @param urlname URLName object to be used for this service
*/
protected Service(Session session, URLName urlname) {
this.session = session;
debug = session.getDebug();
url = urlname;
/*
* Initialize the URLName with default values. The URLName will be updated when connect is called.
*/
String protocol = null;
String host = null;
int port = -1;
String user = null;
String password = null;
String file = null;
// get whatever information we can from the URL
// XXX - url should always be non-null here, Session
// passes it into the constructor
if (url != null) {
protocol = url.getProtocol();
host = url.getHost();
port = url.getPort();
user = url.getUsername();
password = url.getPassword();
file = url.getFile();
}
// try to get protocol-specific default properties
if (protocol != null) {
if (host == null)
host = session.getProperty("mail." + protocol + ".host");
if (user == null)
user = session.getProperty("mail." + protocol + ".user");
}
// try to get mail-wide default properties
if (host == null)
host = session.getProperty("mail.host");
if (user == null)
user = session.getProperty("mail.user");
// try using the system username
if (user == null) {
try {
user = System.getProperty("user.name");
} catch (SecurityException sex) {
// XXX - it's not worth creating a MailLogger just for this
// logger.log(Level.CONFIG, "Can't get user.name property", sex);
}
}
url = new URLName(protocol, host, port, file, user, password);
// create or choose the appropriate event queue
String scope = session.getProperties().getProperty("mail.event.scope", "folder");
Executor executor = (Executor) session.getProperties().get("mail.event.executor");
if (scope.equalsIgnoreCase("application"))
q = EventQueue.getApplicationEventQueue(executor);
else if (scope.equalsIgnoreCase("session"))
q = session.getEventQueue();
else // if (scope.equalsIgnoreCase("store") ||
// scope.equalsIgnoreCase("folder"))
q = new EventQueue(executor);
}
/**
* A generic connect method that takes no parameters. Subclasses can implement the appropriate authentication schemes. Subclasses that need additional information might want to use some properties
* or might get it interactively using a popup window.
*
* If the connection is successful, an "open" ConnectionEvent is delivered to any ConnectionListeners on this service.
*
* Most clients should just call this method to connect to the service.
*
* It is an error to connect to an already connected service.
*
* The implementation provided here simply calls the following connect(String, String, String) method with nulls.
*
* @exception AuthenticationFailedException for authentication failures
* @exception MessagingException for other failures
* @exception IllegalStateException if the service is already connected
* @see javax.mail.event.ConnectionEvent
*/
public void connect() throws MessagingException {
connect(null, null, null);
}
/**
* Connect to the specified address. This method provides a simple authentication scheme that requires a username and password.
*
* If the connection is successful, an "open" ConnectionEvent is delivered to any ConnectionListeners on this service.
*
* It is an error to connect to an already connected service.
*
* The implementation in the Service class will collect defaults for the host, user, and password from the session, from the URLName for this service, and from the supplied parameters
* and then call the protocolConnect method. If the protocolConnect method returns false, the user will be prompted for any missing information and the
* protocolConnect method will be called again. The subclass should override the protocolConnect method. The subclass should also implement the getURLName
* method, or use the implementation in this class.
*
* On a successful connection, the setURLName method is called with a URLName that includes the information used to make the connection, including the password.
*
* If the username passed in is null, a default value will be chosen as described above. If the password passed in is null and this is the first successful connection to this service, the user
* name and the password collected from the user will be saved as defaults for subsequent connection attempts to this same service when using other Service object instances (the connection
* information is typically always saved within a particular Service object instance). The password is saved using the Session method setPasswordAuthentication. If the password passed
* in is not null, it is not saved, on the assumption that the application is managing passwords explicitly.
*
* @param host the host to connect to
* @param user the user name
* @param password this user's password
* @exception AuthenticationFailedException for authentication failures
* @exception MessagingException for other failures
* @exception IllegalStateException if the service is already connected
* @see javax.mail.event.ConnectionEvent
* @see javax.mail.Session#setPasswordAuthentication
*/
public void connect(String host, String user, String password) throws MessagingException {
connect(host, -1, user, password);
}
/**
* Connect to the current host using the specified username and password. This method is equivalent to calling the connect(host, user, password) method with null for the host name.
*
* @param user the user name
* @param password this user's password
* @exception AuthenticationFailedException for authentication failures
* @exception MessagingException for other failures
* @exception IllegalStateException if the service is already connected
* @see javax.mail.event.ConnectionEvent
* @see javax.mail.Session#setPasswordAuthentication
* @see #connect(java.lang.String, java.lang.String, java.lang.String)
* @since JavaMail 1.4
*/
public void connect(String user, String password) throws MessagingException {
connect(null, user, password);
}
/**
* Similar to connect(host, user, password) except a specific port can be specified.
*
* @param host the host to connect to
* @param port the port to connect to (-1 means the default port)
* @param user the user name
* @param password this user's password
* @exception AuthenticationFailedException for authentication failures
* @exception MessagingException for other failures
* @exception IllegalStateException if the service is already connected
* @see #connect(java.lang.String, java.lang.String, java.lang.String)
* @see javax.mail.event.ConnectionEvent
*/
public synchronized void connect(String host, int port, String user, String password) throws MessagingException {
// see if the service is already connected
if (isConnected())
throw new IllegalStateException("already connected");
PasswordAuthentication pw;
boolean connected = false;
boolean save = false;
String protocol = null;
String file = null;
// get whatever information we can from the URL
// XXX - url should always be non-null here, Session
// passes it into the constructor
if (url != null) {
protocol = url.getProtocol();
if (host == null)
host = url.getHost();
if (port == -1)
port = url.getPort();
if (user == null) {
user = url.getUsername();
if (password == null) // get password too if we need it
password = url.getPassword();
} else {
if (password == null && user.equals(url.getUsername()))
// only get the password if it matches the username
password = url.getPassword();
}
file = url.getFile();
}
// try to get protocol-specific default properties
if (protocol != null) {
if (host == null)
host = session.getProperty("mail." + protocol + ".host");
if (user == null)
user = session.getProperty("mail." + protocol + ".user");
}
// try to get mail-wide default properties
if (host == null)
host = session.getProperty("mail.host");
if (user == null)
user = session.getProperty("mail.user");
// try using the system username
if (user == null) {
try {
user = System.getProperty("user.name");
} catch (SecurityException sex) {
// XXX - it's not worth creating a MailLogger just for this
// logger.log(Level.CONFIG, "Can't get user.name property", sex);
}
}
// if we don't have a password, look for saved authentication info
if (password == null && url != null) {
// canonicalize the URLName
setURLName(new URLName(protocol, host, port, file, user, null));
pw = session.getPasswordAuthentication(getURLName());
if (pw != null) {
if (user == null) {
user = pw.getUserName();
password = pw.getPassword();
} else if (user.equals(pw.getUserName())) {
password = pw.getPassword();
}
} else
save = true;
}
// try connecting, if the protocol needs some missing
// information (user, password) it will not connect.
// if it tries to connect and fails, remember why for later.
AuthenticationFailedException authEx = null;
try {
connected = protocolConnect(host, port, user, password);
} catch (AuthenticationFailedException ex) {
authEx = ex;
}
// if not connected, ask the user and try again
if (!connected) {
InetAddress addr;
try {
addr = InetAddress.getByName(host);
} catch (UnknownHostException e) {
addr = null;
}
pw = session.requestPasswordAuthentication(addr, port, protocol, null, user);
if (pw != null) {
user = pw.getUserName();
password = pw.getPassword();
// have the service connect again
connected = protocolConnect(host, port, user, password);
}
}
// if we're not connected by now, we give up
if (!connected) {
if (authEx != null)
throw authEx;
else if (user == null)
throw new AuthenticationFailedException("failed to connect, no user name specified?");
else if (password == null)
throw new AuthenticationFailedException("failed to connect, no password specified?");
else
throw new AuthenticationFailedException("failed to connect");
}
setURLName(new URLName(protocol, host, port, file, user, password));
if (save)
session.setPasswordAuthentication(getURLName(), new PasswordAuthentication(user, password));
// set our connected state
setConnected(true);
// finally, deliver the connection event
notifyConnectionListeners(ConnectionEvent.OPENED);
}
/**
* The service implementation should override this method to perform the actual protocol-specific connection attempt. The default implementation of the connect method calls this
* method as needed.
*
* The protocolConnect method should return false if a user name or password is required for authentication but the corresponding parameter is null; the
* connect method will prompt the user when needed to supply missing information. This method may also return false if authentication fails for the supplied user name or
* password. Alternatively, this method may throw an AuthenticationFailedException when authentication fails. This exception may include a String message with more detail about the failure.
*
* The protocolConnect method should throw an exception to report failures not related to authentication, such as an invalid host name or port number, loss of a connection during the
* authentication process, unavailability of the server, etc.
*
* @param host the name of the host to connect to
* @param port the port to use (-1 means use default port)
* @param user the name of the user to login as
* @param password the user's password
* @return true if connection successful, false if authentication failed
* @exception AuthenticationFailedException for authentication failures
* @exception MessagingException for non-authentication failures
*/
protected boolean protocolConnect(String host, int port, String user, String password) throws MessagingException {
return false;
}
/**
* Is this service currently connected?
*
* This implementation uses a private boolean field to store the connection state. This method returns the value of that field.
*
* Subclasses may want to override this method to verify that any connection to the message store is still alive.
*
* @return true if the service is connected, false if it is not connected
*/
public synchronized boolean isConnected() {
return connected;
}
/**
* Set the connection state of this service. The connection state will automatically be set by the service implementation during the connect and close methods. Subclasses
* will need to call this method to set the state if the service was automatically disconnected.
*
* The implementation in this class merely sets the private field returned by the isConnected method.
*
* @param connected true if the service is connected, false if it is not connected
*/
protected synchronized void setConnected(boolean connected) {
this.connected = connected;
}
/**
* Close this service and terminate its connection. A close ConnectionEvent is delivered to any ConnectionListeners. Any Messaging components (Folders, Messages, etc.) belonging to this service
* are invalid after this service is closed. Note that the service is closed even if this method terminates abnormally by throwing a MessagingException.
*
* This implementation uses setConnected(false) to set this service's connected state to false. It will then send a close ConnectionEvent to any registered
* ConnectionListeners. Subclasses overriding this method to do implementation specific cleanup should call this method as a last step to insure event notification, probably by including a call to
* super.close() in a finally clause.
*
* @see javax.mail.event.ConnectionEvent
* @throws MessagingException for errors while closing
*/
public synchronized void close() throws MessagingException {
setConnected(false);
notifyConnectionListeners(ConnectionEvent.CLOSED);
}
/**
* Return a URLName representing this service. The returned URLName does not include the password field.
*
* Subclasses should only override this method if their URLName does not follow the standard format.
*
* The implementation in the Service class returns (usually a copy of) the url field with the password and file information stripped out.
*
* @return the URLName representing this service
* @see URLName
*/
public URLName getURLName() {
URLName url = this.url; // snapshot
if (url != null && (url.getPassword() != null || url.getFile() != null))
return new URLName(url.getProtocol(), url.getHost(), url.getPort(), null /* no file */, url.getUsername(), null /* no password */);
else
return url;
}
/**
* Set the URLName representing this service. Normally used to update the url field after a service has successfully connected.
*
* Subclasses should only override this method if their URL does not follow the standard format. In particular, subclasses should override this method if their URL does not require all the
* possible fields supported by URLName; a new URLName should be constructed with any unneeded fields removed.
*
* The implementation in the Service class simply sets the url field.
*
* @param url the URLName
* @see URLName
*/
protected void setURLName(URLName url) {
this.url = url;
}
/**
* Add a listener for Connection events on this service.
*
* The default implementation provided here adds this listener to an internal list of ConnectionListeners.
*
* @param l the Listener for Connection events
* @see javax.mail.event.ConnectionEvent
*/
public void addConnectionListener(ConnectionListener l) {
connectionListeners.addElement(l);
}
/**
* Remove a Connection event listener.
*
* The default implementation provided here removes this listener from the internal list of ConnectionListeners.
*
* @param l the listener
* @see #addConnectionListener
*/
public void removeConnectionListener(ConnectionListener l) {
connectionListeners.removeElement(l);
}
/**
* Notify all ConnectionListeners. Service implementations are expected to use this method to broadcast connection events.
*
* The provided default implementation queues the event into an internal event queue. An event dispatcher thread dequeues events from the queue and dispatches them to the registered
* ConnectionListeners. Note that the event dispatching occurs in a separate thread, thus avoiding potential deadlock problems.
*
* @param type the ConnectionEvent type
*/
protected void notifyConnectionListeners(int type) {
/*
* Don't bother queuing an event if there's no listeners. Yes, listeners could be removed after checking, which just makes this an expensive no-op.
*/
if (connectionListeners.size() > 0) {
ConnectionEvent e = new ConnectionEvent(this, type);
queueEvent(e, connectionListeners);
}
/*
* Fix for broken JDK1.1.x Garbage collector : The 'conservative' GC in JDK1.1.x occasionally fails to garbage-collect Threads which are in the wait state. This would result in thread (and
* consequently memory) leaks. We attempt to fix this by sending a 'terminator' event to the queue, after we've sent the CLOSED event. The terminator event causes the event-dispatching thread
* to self destruct.
*/
if (type == ConnectionEvent.CLOSED)
q.terminateQueue();
}
/**
* Return getURLName.toString() if this service has a URLName, otherwise it will return the default toString.
*/
@Override
public String toString() {
URLName url = getURLName();
if (url != null)
return url.toString();
else
return super.toString();
}
/**
* Add the event and vector of listeners to the queue to be delivered.
*
* @param event the event
* @param vector the vector of listeners
*/
protected void queueEvent(MailEvent event, Vector vector) {
/*
* Copy the vector in order to freeze the state of the set of EventListeners the event should be delivered to prior to delivery. This ensures that any changes made to the Vector from a target
* listener's method during the delivery of this event will not take effect until after the event is delivered.
*/
@SuppressWarnings("unchecked")
Vector v = (Vector) vector.clone();
q.enqueue(event, v);
}
/**
* Stop the event dispatcher thread so the queue can be garbage collected.
*/
@Override
protected void finalize() throws Throwable {
try {
q.terminateQueue();
} finally {
}
}
/**
* Package private method to allow Folder to get the Session for a Store.
*/
protected Session getSession() {
return session;
}
/**
* Package private method to allow Folder to get the EventQueue for a Store.
*/
EventQueue getEventQueue() {
return q;
}
}