MSCA/MWA Framework - Custom Development and Extension - Part 2

Technical Overview of MSCA/MWA Framework Continues...

Event Listener Model

MWAEvent

• Event object passed to the listener methods in the handlers at the field, page, or app level. 
• public class MWAEvent extends java.util.EventObject
  
• Frequently used properties and their getters and setters inherited from EventObject
• public Object getSource()
• public String toString()
• Stores action property (private java.lang.String m_action)
• public java.lang.String getAction()
  
• Stores session property (private oracle.apps.mwa.container.Session m_session)
• public Session getSession()
  

MWAEvent Listeners:

Listeners are utilised for validations, dynamic rendering of the fields, update the values etc. Following are the key Listeners:

1. oracle.apps.mwa.eventmodel.MWAListener
• Parent class for all MWA Listeners.
• public interface MWAListener extends java.util.EventListener
  
• Direct subinterfaces - MWAAppListener, MWAPageListener, MWAFieldListener
• We don't implement this interface directly.

2. oracle.apps.mwa.eventmodel.MWAAppListener
• Application Level Event Listener
• public interface MWAAppListener extends MWAListener
• Methods - 
• void appEntered(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• void appExited(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• This interface is& typically implemented by our custom application's menu item bean.

3. oracle.apps.mwa.eventmodel.MWAPageListener
• Page Level Event Listener
• public interface MWAPageListener extends MWAListener
• Methods - 
• void pageEntered (MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• void pageExited(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• void specialKeyPressed(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• Ex. Generating Barcodes, Navigating to Main menu etc.
• This interface is typically implemented by our custom application's page bean.

4. oracle.apps.mwa.eventmodel.MWAFieldListener
• Field Level Event Listener
• public interface 

  MWAFieldListener

   extends MWAListener
• Methods - 
• void fieldEntered(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• void fieldExited(MWAEvent e) throws AbortHandlerException, InterruptedHandlerException, DefaultOnlyHandlerException
• Probably most important class in terms of the custom code that we need to write in this.
• This interface is typically implemented in a standalone class.
• The standalone field listener class is instantiated and referenced inside page bean, where we associate it with every field on the page.
• Field Listener will typically have a constructor where session is passed from page and stored in a class variable.
• Following are few important code snippet typically used in this field listeners:
• To get the source of the event:
• String fieldName = ((FieldBean)mwaEvent.getSource()).getName();
• To check if it is a submit event:
• if (mwaEvent.getAction().equals("MWA_SUBMIT"))
• To get the current page details
• session.getCurrentPage();
• To show message in status bar:
• this.ses.setStatusMessage("Qty Should be > 0");
• this.ses.setStatusMessage("Trx Successful");
• To set next field for user entry:
• session.setNextFieldName();
• To refresh the screen:
• session.setRefreshScreen();
• To throw exceptions:
• throw new AbortHandlerException("Qty Should be > 0");
• To signal end of transaction
• setNextPageName("|END_OF_TRANSACTION|")
• Most of the above code is from session, we'll see session details in coming section.

Other Important Classes - MWA Session Classes

• oracle.apps.mwa.container.Session
• public class Session extends oracle.apps.mwa.container.BaseSession
• BaseSession is base class for user session and telnet session.
• Key methods inherited from BaseSession
• public java.sql.Connection getConnection()
• public java.sql.Connection getConnectionFromSession()
• public void returnConnection()
• public java.lang.String getCurrentPageName()
• Key methods in Session class
• public PageBean getCurrentPage()
  
• Returns the current page bean in the page bean list
• public void setStatusMessage(java.lang.String msg)
  
• Displays the argument string on the status bar.
• public java.lang.String getStatusMessage()
  
• public void setRefreshScreen(boolean RefreshScreenFlag)
  
• This method set the refresh screen variable Whenever developer change the UI property of the page, e.g. hidden, value, creation of new field, etc, he/she needs to call this method with parameter true so that server will know and refresh the screen
• public boolean isRefreshScreen()
• public FieldBean getFieldFromCurrentPage(java.lang.String fieldName)
• public void setNextFieldName(java.lang.String fName)
  
• To set the cursor to some other field.
• public java.lang.String getNextFieldName()
  
• public Logger getLogger()
  

Application Flow

Coding Hints:

A. Ctrl + X shortcut key for About This Page is a good start for customizing existing functionality.

B. We typically create following 4 files:

1. XXABCTransactFunction.java
• public class XXABCTransactFunction extends MenuItemBean implements MWAAppListener
• With following two lines in constructor:
• setFirstPageName("xxabc.oracle.apps.xxabc.applpkg.module.server.XXABCTransactPage");
• addListener(this);
• It'll have appEntered() and appExited() methods.
2. XXABCTransactPage.java
• public class XXABCTransactPage extends PageBean implements MWAPageListener
• Typically it'll have following Member variables:
• For all field beans
• For session
• For FieldListener for all fields
• Constructor will initialize FieldListener bean (Explained Next)
• Constructor will initialize all fields, associate field listener and add them to page hierarchy.
• It'll have pageEntered(), pageExited() and specialKeyPressed() methods.
• It'll have methods for business transactions typically calling PLSQL procedures.
3. XXABCTransactFListener.java
• public class XXABCTransactFListener implements MWAFieldListener
• Typically it'll have following Member variables:
• session
• Paramterized Constructor with session variable will initialize member session variable.
• Rarely we need to write code in fieldEntered() method.
• FieldExited() will have bulk of the coding based on current page and field exited:
• String fieldName = ((FieldBean)mwaEvent.getSource()).getName();
• To identify the field exited.
• this.ses.getCurrentPage();
• To identify the current page
• For transaction logic, it'll have a call to the pageBean's transaction method.
4. XXABCFieldLOV.java
• public class XXABCFieldLOV extends LOVFieldBean implements MWAFieldListener
• Since LOVs are shared components, for easy of use/reuse we usually create them as separate Java files.
• It'll have member variables, their getters and setters for the return values of the selected LOV record.
• It'll have constructor will following api calls:
• setName(), setRequired(), setPrompt(), setValidateFromLOV(), setlovStatement(), setInputParameterTypes(), setSubfieldPrompts(), setSubfieldDisplays(), addListener(this).
• It'll have fieldEntered() method (usually empty).
• It'll have fieldExited() method (usually we set all the return values from selected LOV record to member variables).

Sample Code for all Files:

Standard Oracle MWA code provides good insight in how to write code. If still any help is needed, please reach me.

Steps to test the code:

• Deploy it on the server.
• Restart the server.
• Testing on desktop telnet client.
• View the log for debugging.

Debugging:

• Steps to enable logging are in document 338291.1
• Log files are located in $INST_TOP/logs
• Logging Levels are Fatal, Error, Warning, Debug and Trace.
• All Log files start with telnet port number as prefix.
• In java code following method is used to write log statement:
• oracle.apps.inv.utilities.server.UtilFns.trace() 
• In java code to check if trace is enabled:
• if (UtilFns.isTraceOn)
• In PLSQL, following code will be used
• Use Mirroring
• Check Mobile Services are up and Runing:
• ps -ef |grep mwa
• ./ $INST_TOP/admin/scripts/mwactl.sh status
• Check MWA user sessions
• netstat -a |grep <MWA PORT> | wc -l
• netstat -an | grep <MWA PORT>
• Find port Number of Mobile Services :
• grep mwa $CONTEXT_FILE
• Connect to Mobile Services :
• telnet hostname.domainname portnumber(mobile application service port_number)
• MWA Troubleshooting Tips for Release 12 (Doc ID 782162.1)

Reference and Further Reading:

Note 578667.1 - Customization of Oracle Mobile Supply Chain Applications and Oracle Warehouse Management System
Note 959087.1 - How To Download The MSCA/WMS JAVADOCS Files For Doing Customization?
Note 338291.1 - How to Enable WMS / MSCA Logging
Note 297992.1 - Advanced Barcode Strategies – Custom Scan Framework & profile option "MWA: Custom Scan"
For Multi-lingual Support and DFI (Data Field Identifier) - Integration with AK repository is needed.

Previous Read: MSCA/MWA Framework - Custom Development and Extension - Part 1
Previous Read: Oracle MSCA/MWA Framework - Introduction