Opportunity Contact Roles in VF Controller

Question

I have a custom Visualforce controller that applies to a custom object (SF__c). This object has a master-detail to the Opportunity object. My controller pre-populates the SF__c object with the Opportunity ID and the Owner ID upon creation. I would also like to populate a Contact__c field on the SF__c object with a Contact Role on the Opportunity that has a Role of "Signer". Does anyone know how I can do this in my controller?

public class VF_SFController{

public List<SF__c> ESF {get; set;}

    private final Opportunity opp;
    public VF_SFController(ApexPages.StandardController myController){
        SF = new List<SF__c>();
        myController.addFields(new List<String>{'Id', 'OwnerId', 'Owner.Phone'});
        opp=(Opportunity)myController.getrecord();
    }

    public SF__c SF2 = new SF__c();
        public void SF(){

            SF2.Opportunity__c = opp.Id;
            SF2.Rep__c = opp.OwnerId;
            SF.add(SF2);
        }


    public PageReference save() {

        insert SF;

       PageReference RetPage = new PageReference('/apex/VFSFView?id=' + SF[0].id);
        RetPage.setRedirect(true);
        return RetPage; 
    }

}

Answer 1

Assuming that

public void SF(){

        SF2.Opportunity__c = opp.Id;
        SF2.Rep__c = opp.OwnerId;
        SF.add(SF2);
    }

is your page action method, you could extend it to:

public void SF(){

        SF2.Opportunity__c = opp.Id;
        SF2.Rep__c         = opp.OwnerId;

        Opportunity o = select id (select id, contactId from OpportunityContactRoles
                              where role = 'Signer' order by lastModifiedDate desc limit 1)
                           from Opportunity where id = :opp.id];
        SF2.contactId = o.opportunityContactRoles.size() != 0 
                        ? o.opportunityContactRoles[0].contactId  
                        : null 
        SF.add(SF2);
    }