com.echomine.jabber

Class JabberMessageHandler

java.lang.Object

com.echomine.jabber.JabberMessageHandler

Direct Known Subclasses:

JDOMMessageHandler

public abstract class JabberMessageHandler
extends java.lang.Object

Handles incoming message and creates the proper message object to contain the incoming parse data. It is pretty much a message processor. The handler works in conjunction with the Message Builder, but it doesn't always need to use the message builder.

The way message handling works is pretty simple.

1. message comes in through the low-level sax content handler.
2. content handler looks up a list of handler that can handle incoming elements.
3. content obtain reference of the handler and delegates the rest of the data to the handler.
4. handler receives data, creating new message objects each time that it is called to start a new object. Optionally, the handler can delegate the task of creating new message objects to the Message Builders (this is default behavior for the module).
5. message is then sent out to the message listener.

Pretty much each message type will require its own message handler OR message builder. Most of the time you will not need to create a message handler unless it's your desire to work directly with the SAX events (ie. you are not interested in using JDOM for DOM processing). Register a message builder and you are good to go.

The way the methods here are called is very similar to the way SAX Handlers are called.

1. when a new message starts, startMessage() is called. (same as startDocument).
2. Elements are then received through startElement() and endElement().
3. When the end of the message is reached, endMessage() is called.
4. Then getMessage() will hand it off to a message builder to instantiate a message object of the approriate type.

Note that the first element received through startElement() is the beginning of the message itself.

Constructor Summary

Constructors

Constructor and Description
JabberMessageHandler(JabberMessageParser msgParser)

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	characters(char[] ch, int start, int length) the methods that must be implemented to work with the XML content that's coming in
abstract void	endElement(java.lang.String namespaceURI, java.lang.String localName, java.lang.String qName) the methods that must be implemented to work with the XML content that's coming in
abstract void	endMessage() This method is called when the end of the message is reached.
abstract JabberMessage	getMessage()
JabberMessageParser	getMessageParser()
abstract void	startElement(java.lang.String namespaceURI, java.lang.String localName, java.lang.String qName, org.xml.sax.Attributes attr) the methods that must be implemented to work with the XML content that's coming in
abstract void	startMessage() This method is called when the beginning of the message is received.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JabberMessageHandler

public JabberMessageHandler(JabberMessageParser msgParser)

Method Detail

getMessageParser

public JabberMessageParser getMessageParser()

startMessage

public abstract void startMessage()

This method is called when the beginning of the message is received. Any sort of resetting or initializing should be done here.

endMessage

public abstract void endMessage()

This method is called when the end of the message is reached. Any sort of resetting or destroying should be done here. Normally, nothing needs to be done, but you may need to do some post processing if you want.

startElement

public abstract void startElement(java.lang.String namespaceURI,
                java.lang.String localName,
                java.lang.String qName,
                org.xml.sax.Attributes attr)

the methods that must be implemented to work with the XML content that's coming in

endElement

public abstract void endElement(java.lang.String namespaceURI,
              java.lang.String localName,
              java.lang.String qName)

the methods that must be implemented to work with the XML content that's coming in

characters

public abstract void characters(char[] ch,
              int start,
              int length)

the methods that must be implemented to work with the XML content that's coming in

getMessage

public abstract JabberMessage getMessage()