public void addVarRefExpr ( final INodeReadTrx mTransaction , final String mVarName ) { final VariableAxis axis = ( VariableAxis ) mVarRefMap . get ( mVarName ) ; if ( axis != null ) { getExpression ( ) . add ( new VarRefExpr ( mTransaction , axis ) ) ; } else { throw new IllegalStateException ( "Variable " + mVarName + " unkown." ) ; } }
Adds a VarRefExpr to the pipeline . This Expression holds a reference to the current context item of the specified variable .