Bug 141255 No error for the incompatible parameter value
Steps to reproduce: 1.New a decimal parameter, set the default value to "aaa" 2.Preview the report by "Preview" tab Expected result: Error to say the incompatible parameter value Actual result: Parameter request page keeps poping up till input the decimal value Note: if preview in Web Viewer, error will be thrown out, but no exception description.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/presentation/aggregation/parameter/ScalarParameterFragment.java
: displayName;
		displayName = ParameterAccessor.htmlEncode( displayName );
		parameterBean.setDisplayName( displayName );
		
		InputOptions options = new InputOptions( );
		options.setOption( InputOptions.OPT_REQUEST, request );
		Object paramDefaultValueObj = service.getParameterDefaultValue(
				designHandle, parameterBean.getName( ), options );
		
		switch ( parameter.getDataType( ) )
		{
			case ParameterDefinition.TYPE_STRING :
			{
				
				
				parameterBean.setRequired( false );
				if ( paramDefaultValueObj == null && !parameter.allowNull( ) )
				{
					parameterBean.setRequired( true );
				}
				else if ( paramDefaultValueObj != null
						&& ( (String) paramDefaultValueObj ).length( ) <= 0
						&& !parameter.allowBlank( ) )
				{
					parameterBean.setRequired( true );
				}
				break;
			}
			default :
			{