boSession & EboContext

Each time a user logs to a XEO application a boSession instance is created to represent the session of the user whithin the application

boSession

The boSession instance

When using XEO's Web Component Layer, the login is made through a web form which will automatically create a boSession instance for the user (and EboContext instances as well), so there's usually no need to explicitely create boSession instances, unless you're creating a custom JSP/Servlet and need to programatically connect to the XEO Application.

EboContext

Every request made to a XEO Application to load/create boObject instances must be contained in a context. EboContext is the class that implements that "context" and is where instances of boObjects are stored wheneved they are created/loaded. EboContext is also the place where transactional control can happen (there's another alternative in boObject (getUpdateQueue).Transactions created by using EboContext methods are JTA ( Java Transactional API) transactions which means you can mix DML statements with your object creation and update inside a transaction and commit on success/rollback on failure, see an example bellow.

EboContext instances are generally created by the XEO Runtime and can be accessed from several places, such as from any instance of a boObject throught the getEboContext() method. If you recall from the methods generated by XEO Studio for the required/defaultValue and such methods, one of the parameters was the boObject instance. Bellow, see the table of important methods in the EboContext class.

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Safe Ebo Context Usage Example

        boSession session = null;
        EboContext context = null;
        boApplication xeoApp = boApplication.getDefaultApplication();
        try {
                session = xeoApp.boLogin("USERNAME", "PASSWORD");        
                context = xeoApp.createContext(session);
                  
                //Your code in here

        } catch (Exception e) {
                 //Process the exception in case of error
        } finally {
            if (context!=null)
                context.close();
            if (session!=null)
                session.closeSession();
        }

Using JTA Transactions Example

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//Declare variables
        boApplication app = null;
        boSession session = null;
        EboContext ctx = null;
        
        try{
                //Get the application instance
                app = boApplication.getDefaultApplication();
                //Login a user
                session = app.boLogin("SYSUSER", "ABC");
                //Create a context
                ctx = app.createContext(session);
        
                //Start Transaction 
                ctx.beginContainerTransaction();
            
                try{
                    
                    //Create Object, set an attribute and save
                    boObject obj = app.getObjectManager().createObject(ctx, "MyObj");
                    obj.getAttribute("att").setValueString("foo");
                    obj.update();
                    
                    //Make a DML statement to insert some values in database
                    Connection conn = null;
                    Statement stmt = null;
                    
                    //Retrieve the connection and execute the query
                    conn = ctx.getConnectionData();
                    stmt = conn.createStatement(
                            ResultSet.TYPE_SCROLL_SENSITIVE,
                            ResultSet.CONCUR_READ_ONLY);
                    stmt.executeQuery("INSERT INTO MY_TABLE VALUES('foo','bar')");
                    
                    //Commit the changes
                    ctx.commitContainerTransaction();
                }
                catch (Exception e){
                    //If anything goes wrong roll back the transaction
                    ctx.rollbackContainerTransaction();
                }
        }
        catch (boRuntimeException e ){
            //Deal with the exception during execution
        } catch (boLoginException e) {
            // Deal with login exception 
        }finally{
            //Close all used resources
            if (ctx != null) ctx.close();
            if (session != null) session.closeSession();
        }

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