Bug 121111 Bad event handler class name does not cause an error
Open a report design, open any Data Set's Property editor. Type in an invalid Java class name for the "Event Handler Class" property, say "aaa". Preview a report that uses that Data Set. The report executes normally. No error is shown. Event handlers are an integral part of a report design, and if a script handler class is not found, or if the handler throws a runtime exception, Report Engine should either stop the report execution, or show the error message in the generated report. (Tested with the 2005-12-15 nightly build)
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/adapter/ModelDteApiAdapter.java
* @throws EngineException
	 */
	IComputedColumn newComputedColumn( ComputedColumnHandle modelCmptdColumn )
			throws EngineException
	{
		
		if ( modelCmptdColumn.getExpression( ) == null )
		{
			throw new EngineException(
					MessageConstants.MISSING_COMPUTED_COLUMN_EXPRESSION_EXCEPTION,
					modelCmptdColumn.getName( ) );
		}
		return new ComputedColumn( modelCmptdColumn.getName( ),
				modelCmptdColumn.getExpression( ),
				toDteDataType( modelCmptdColumn.getDataType( ) ) );
	}
	/**
	 * Creates a new DtE API IJSExprFilter or IColumnFilter from a model's
	 * filter condition. Could return null if no expression nor column operator
	 * is defined.
	 */
	IFilterDefinition newFilter( FilterConditionHandle modelFilter )
	{
		String filterExpr = modelFilter.getExpr( );
		if ( filterExpr == null || filterExpr.length( ) == 0 )
			return null; 
		
		String filterOpr = modelFilter.getOperator( );
		if ( filterOpr == null || filterOpr.length( ) == 0 )
			return new FilterDefinition( new ScriptExpression( filterExpr ) );