How To make a DFF segment read only programatically

Hi All,I am new to OAF development. Our requirement is to make as existing DFF segment Read only. The condition is to make this read only if the user is present in a specific look up.

I got below code from a forum but it's not working in Oracle Apps 12.1.3 Version.( the line att.setAttributeValue(DISABLED_ATTR,true); is showing strike through in Jdeveloper).

public int getDffSegmentNumber(OAWebBean webBean,String pDffBeanName,String pDffSegName)
{
OADescriptiveFlexBean vDffBean = (OADescriptiveFlexBean)webBean.findChildRecursive(pDffBeanName);
DescriptiveFlexfield vDff = (DescriptiveFlexfield)
vDffBean.getAttributeValue(OAWebBeanConstants.FLEXFIELD_REFERENCE);

boolean isFound = false;

int vSegIdx = 0;
for (int idx=0 ; idx < vDff.getSegmentCount() && !isFound;++idx)