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saxparse.MessageProcessor Class Reference

Collaboration diagram for saxparse.MessageProcessor:

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Detailed Description

MessageProcessor Aug 10, 2004.

The SAX "call back" handler for the trade engine message processor classes.

The methods in this class are called when the SAX parser recognizes the components of an XML document. The MessageProcessor class handles the document start (the message envelope) and recognizes the start of each message type. The MessageProcessor class allocates the appropriate message processor (derived from MessageBaseMessage base class) for each message. Calls the element, endElement and characters methods in the message processor to process the start tag, characters region and end tag. Note that the state machine below skips the first tag that starts a message (e.g., aim_order).

The MessageProcessor is passed a reference to an ArrayList. After each message is processed it is added to the ArrayList.

Trade engine messages are packaged within a tradeEngine XML envelope. This allows multiple sub-messages to be included in one tradeEngine message.

Author:
Ian Kaplan, www.bearcave.com, iank@bearcave.com


Public Member Functions

 MessageProcessor (ArrayList msgList)
void warning (SAXParseException e)
void error (SAXParseException e) throws SAXParseException
void fatalError (SAXParseException e) throws SAXParseException
void startDocument ()
void endDocument ()
void characters (char[] charSeq, int start, int len)
 The characters method is called to process character sequences that occur between tags.
void startElement (String uri, String localName, String qualName, Attributes attributes)
void endElement (String uri, String localName, String qualName)

Private Attributes

States mCurrentState = States.BAD_STATE
MessageInterface mMessage = null
ArrayList mMsgList = null

Constructor & Destructor Documentation

saxparse.MessageProcessor.MessageProcessor (  ArrayList  msgList  ) 
  

00080     {
00081         super();
00082         mMsgList = msgList;
00083     }

Member Function Documentation

void saxparse.MessageProcessor.characters (  char[]  charSeq,
int  start,
int  len
) 
 

The characters method is called to process character sequences that occur between tags.

For example: 

            <TAG>This is a String</TAG>

This also includes white space that may be used in formatting the XML.

The SAX parser passes a reference to the input character array for the entire XML document. The start parameter is the offset in this array to the character region and the len parameter is its length.

Here I'm not interested in white space, so if the character region is nothing but white space, the method just returns. 

00135     {
00136         String str = new String( charSeq, start, len );
00137         str = str.trim();
00138         if (str.length() > 0) {
00139             if (mMessage != null && mCurrentState == States.PROCESSING ) {
00140                 mMessage.characters( str );
00141             }
00142         }
00143     } // characters

void saxparse.MessageProcessor.endDocument (   ) 
  

00109     {
00110     }

void saxparse.MessageProcessor.endElement (  String  uri,
String  localName,
String  qualName
) 
  

00178     {
00179         if (!localName.equals("tradeEngine")) {
00180             if (localName.equals("aim_order") ||
00181                 localName.equals("control")) {
00182                 mCurrentState = States.DONE;
00183                 if (mMessage != null) {
00184                     MessageBase m = mMessage.getMessage();
00185                     mMsgList.add( m );
00186                 }
00187                 else {
00188                     System.out.println("MessageProcessor::endElement: mMessage == null");
00189                 }
00190             }
00191             else {
00192                 if (mMessage != null && mCurrentState == States.PROCESSING ) {
00193                     mMessage.endElement( localName );
00194                 }
00195             }
00196         }
00197     } // endElement

void saxparse.MessageProcessor.error (  SAXParseException  e  )  throws SAXParseException
  

00093     {
00094         throw e;
00095     } // error

void saxparse.MessageProcessor.fatalError (  SAXParseException  e  )  throws SAXParseException
  

00099     {
00100         throw e;
00101     } // fatalError

void saxparse.MessageProcessor.startDocument (   ) 
  

00104     {
00105         mCurrentState = States.STATE_ZERO;
00106     }

void saxparse.MessageProcessor.startElement (  String  uri,
String  localName,
String  qualName,
Attributes  attributes
) 
  

00151     {
00152         if (mCurrentState == States.START_MSG) {
00153             mCurrentState = States.PROCESSING;
00154         }
00155         else {
00156             if (localName.equals("tradeEngine")) {
00157                 mCurrentState = States.ENVELOPE;
00158             }
00159             else if (localName.equals("aim_order")) {
00160                 mMessage = new AimOrderMessage();
00161                 mCurrentState = States.START_MSG;
00162             }
00163             else if (localName.equals("control")) {
00164                 mMessage = new ControlMessage();
00165                 mCurrentState = States.START_MSG;
00166             }
00167         }
00168 
00169         if (mMessage != null && mCurrentState == States.PROCESSING ) {
00170             mMessage.element( localName, attributes );
00171         }
00172     } // startElement

void saxparse.MessageProcessor.warning (  SAXParseException  e  ) 
  

00087     {
00088         System.out.println("MessageProcessor: SAXWarning = " + e );
00089     } // warning

Member Data Documentation

States saxparse.MessageProcessor.mCurrentState = States.BAD_STATE [private]
 

MessageInterface saxparse.MessageProcessor.mMessage = null [private]
 

ArrayList saxparse.MessageProcessor.mMsgList = null [private]
 

The documentation for this class was generated from the following file:
Generated on Sat Aug 28 13:50:04 2004 for SaxParse by doxygen 1.3.8