Bug 179743 Parameter Validate Event is not Called
I have tested the validate event on parameters and it never appears to get called.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
{
			return;
		}
		parameterChanged = false;
		
		executionContext.clearParameters( );
		runValues.clear( );
		
		Iterator iterator = inputValues.entrySet( ).iterator( );
		while ( iterator.hasNext( ) )
		{
			Map.Entry entry = (Map.Entry) iterator.next( );
			Object key = entry.getKey( );
			ParameterAttribute attribute = (ParameterAttribute) entry
					.getValue( );
			runValues.put( key, attribute.getValue( ) );
			executionContext.setParameter( (String) key, attribute.getValue( ),
					attribute.getDisplayText( ) );
		}
		if ( runnable == null )
		{
			return;
		}
		
		new ParameterVisitor( ) {
			boolean visitScalarParameter( ScalarParameterHandle param,
					Object userData )
			{
				String name = param.getName( );
				if ( !inputValues.containsKey( name ) )